Squashed 'externals/fmt/' changes from 9e8b86fd2..b6f4ceaed

b6f4ceaed Update version
15f812dae Update changelog
6884aab49 Update changelog
88ec4e706 Bump version
dd3d2490e Update changelog
739055ae7 Fix apidocs
dbbd711f4 Suppress a warning
98cbb6a43 Fix ABI compatiblity issue
214cf13f1 Fix endianness bug in write_digit2_separated (#2699)
17a5c808d Restore FMT_API on error_handler::on_error() (#2696)
fc1783fcc Avoid undefined symbols with mingw-w64 (#2692)
1b193e7b3 Deprecate more
8e59744b8 Switch to new github auth mechanism
7081a6aa3 Update version
64dc8fbad Bump version
fc8e3de7d Fix manage.py script
57bee9fcd Fix formating
dce52e491 Update changelog
9405a4724 Update changelog
495b8bf12 Update changelog
e221166fa Update changelog
035cab8da Update changelog
89c6ed12b Clarify in comments (for now) deprecated map functions
e462da828 Add some noexcept (#2684)
79c66d66b Update changelog
5d37f705f Update changelog
6bb370cec Update changelog
bb6920157 Fix tuple join
4fac7daae Cleanup bit_cast
3617c2795 Update changelog
9c0c1bcdb Simplify tuple formatting
187e8db1b Update changelog
c7f88180f add tests for format string compile-time checks
8a2c3fb88 add reverse tests to compile-error-test
1164eda5a disable compile-error-test on Windows
4482f6f1f rewrite compile-error-test to use non-header-only library
796662a61 Escape range items convertible to std::string_view
33ee4cc51 Improve noexception test
3bbf2c673 Fix throw with exceptions disabled
074c9c52e Update changelog
3110ec5a2 Update changelog
3014b3d77 Clarify that C strings must be null-terminated
eab2ea9fc Replace an assert with an exception
21ed92a6e Update changelog
04111dd1e Fix issue #2670 (#2671)
817788fbf remove incorrect C++20 check from test/CMakeLists.txt (#2663)
4511030af Minor code style tweaks for consistency
7812813a3 Don't explicitly delete copy ctor of dynamic_format_arg_store (#2664)
664cd6067 Remove std-format-test
784e2a7b4 Fix an overflow when formatting very large durations
fc2a376d8 Remove two expressions which had no effect (reported by LGTM)
c5aafd8f9 expose headers as SYSTEM depending on special configuration option
eaddd1e3c Fix handling of byte
2d4457758 Try fixing byte regression
e46392ea2 deprecate _format UDL in code using FMT_DEPRECATED
c882790a2 Add a set formatter
121002d70 Add a map formatter
be51ee1ce Disable broken copy ctor of dynamic_format_arg_store
659de779e Fix a UB in parse_format_specs when begin is null
51b14b6c0 remove commented out lines
223a0fa55 move gtest-specific check into gtest/CMakeLists.txt
ef72b471f enable named arguments check in compile-time checks (#2649)
82246b876 fix throw with exceptions disabled (#2647)
35f60377a Update ChangeLog.rst
3a951a66c Avoid qualifying by inline namespace. Fixes #2642. (#2643)
e0136fc8b Qualify calls to make_wformat_args. Fixes #2639. (#2641)
ac1b5f3da Refactor problematic trailing returns in arg_mapper
fd62fba98 Don't convert scoped enums to integers
c652f8243 Make header guard consistent with header name
a9c7b9b8f Clarify that _format is deprecated
e4f0564aa Disable is_streamable for string[_view]
91533d3c3 Minor tweaks to chrono subsecond formatting
0bbc9708f Implement c++20 std::chrono::duration subsecond formatting (#2623)
9d5b9defd Enable tzset only on Windows desktop app (#2633)
215f21a03 Detect overflow on large precision
c240d98ff Optimize tm formatting (Non C-locales and %Z) (#2617)
6ab73113f Mark grow as FMT_CONSTEXPR20 (#2630)
713c7c7c6 Cleanup os.cc
9b1807a8a fix int -> uint warning (#2611)
ec3b097cb [doc] FMT_STRING supports C++14 and no-op in C++11 (#2620)
c472a2781 Fix handling of very large precision in fixed format
201971e29 Make MSVC use [[nodiscard]] (#2615)
acad8cfab Reformat all source code; no functional changes
491ba2dda Annotate fmt::format and fmt::formatted_size as [[nodiscard]]
5abe9e826 Add platform-specific 'z' formatter
be3a3a5ae Use predefined formats for C-locale
a3ab36c80 Formatting of function pointers, member function pointers, member object pointers... (#2610)
19cac63fe Broken link in README.rst
43419a4ad Workaround a bug in gcc
c089f7d49 Simplify std::tm formatter
aa5517f6b Reuse tm_writer in chrono_formatter
50140be7a Reuse tm_writer in weekday formatter
8b8945499 Improve consistency
5380ff4d8 Detect types convertible to unformattable pointers
094b66e81 changed locale retrieval way to a fancy one
b69ae4854 Reorder classes (#2591)
0b843af56 sped up chrono.h formatting for cases without providing locale (#2576)
12b1d8b14 Fix precision 0 with std::chrono::duration and added additional tests. (#2588)
e67f92c55 Cleanup warnings with nvhpc/21.9. (#2582)
812733cc9 const qualify format function for systen_clock
028f22775 Handle implicit conversions in write
5b0aa638c Minor grammar fix
6eaceb5f7 Fix incompatible between docutils 1.18.0 and sphinx 3.3.0 (#2575)
0697c5edb FMT_USE_FCNTL can be predefined (#2573)
1031eedf2 Replacing strftime with std::time_put (#2550)
90034e4c4 Add FMT_ASSERT and validation of values of struct tm members (#2564)
df40e9467 Upgrade `module-test` to msvc 16.11.5 and 17.0-pre5 (#2558)
e6d5059cb Simplify js tag in basic-bootstrap theme (#2562)
3b6e409cd Enable `consteval` for msvc 17.0-pre5 (#2559)
249f03bbb do not detect LLVM based IBMXL compiler (on ppc) as clang (#2555)
7463c8320 Fix overflow for very bigger years (>2*10^9) (#2551)
1266c2b60 Fix handling of exotic character types
684e2fdc9 Minor cleanup
a1d586302 Minor cleanup
7a604cdd9 Cleanup
aeb54b0dd Fix bug on '%Y' and '%C' formats with negative years Requested changes
f88c020fc Generalization of strftime/wcsftime function calls in tests
2eeddba75 Renaming, splitting of functions
275454608 Fix errors in ISO week-base-year formatter
218cecb6d Fix error in test
e9f4453b0 Fix Microsoft Visual Studio 14.0 build
27c3674ce Improve performance
5dc3dd3d4 New tests
f8542cd98 Unified formatters for std::chrono::time_point<std::chrono::system_clock, Duration> and std::tm
4707373d3 Fix year formatter
79c00ad8f Improve ISO week-base-year formatter
fbaaa5906 Improve week of the year formatter
cde44ddb7 Improve year formatter
b04601b91 Switch from std::strftime/std::wcsftime to internal implementation for locale independent formats
d3d30a46f New tests
7911d8d3f Add format spec checker
fbbfc3b03 Reorder formatters
509eac957 Workarounds for implementation-defined std::strftime behavior
85b38190d New tests for all C++11 std::strftime format specifiers
7aca36bca Extending fmt::join to support C++20-only ranges. (#2549)
f5371a75f locale.h -> format.h
febdef43f fix: add workaround for intel parameter pack bug
f56756986 fix: check to make sure both 'if constexpr' and return type deduction are available
dcd282bb2 Namespace qualify calls to get
9c14474d3 Include `<bit>` when using `std::bit_cast`
1e96e0176 Fix compiler flag check (#2540)
7e4bc9451 Speeding up write_significand() (#2499)
26c1ca4c3 Replaced default spec with equivalent one, which is potentially more optimizable (#2537)
1e865b353 Fix docs
4a85db1ce Change default open mode to -rw-r--r-- (#2530)
0a985fd4c Move size_ initialization to initializer list (#2529)
012cc709d Workaround gcc _Pragma bug 59884
d6590e3bd Fix compiler check
134aec40f Fix search in docs
48a476ae0 Update example (#2522)
023c2018f Don't use strlen in constexpr
800d4c8ac Refactor Windows workarounds
32865aeaa changed detection of Intel Compiler Classic to distinguish MS-Windows (#2510)
7b339795a Describe a better approach of how to use {fmt} as a depency in a Bazel project (#2516)
ae9bbe116 Suppress warning C4127 in chrono.h (conditional expression is constant) (#2518)
927dbd134 Misplaced comma in README.rst (#2515)
2a9a77dd8 Remove misplaced comment
1aee4bc90 Refactor FP formatting
e1bd6cc91 Refactor FP formatting
027fcaf05 Replace use_grisu with fallback since Grisu is only one of multiple implemented algorithms
716d69f27 Refactor FP formatting
ff7e73af6 Always run grisu_gen_digits before fallback_format
2976e31ac Refactor format_float
807ee5ec3 Disable consteval in Apple clang
d9a731d48 Add basic support for Bazel (#2505)
9c57357e0 Add `static` to a table (#2509)
2742611ca Fix formatting
5092b198b Document group_digits
b4d9d82e1 make FP formatting available to be used at compile-time (#2426)
d9fd695ac Fix wchar_t tm formatting
92614ecbf Optimize %T in tm formatting
aaeca12d8 Move FMT_MAYBE_UNUSED to format.h where it is used
3d0c7ae38 Move data to format.cc
04e3a79f7 Use memcpy in more cases in copy2
e47e99bb0 Simplify format_decimal (#2498)
9b6b0e403 Remove data
4d1c6034e Deprecate basic_data
a3348eccd Deprecate most of basic_data
3a0448148 Remove data::hex_digits
ad77331c0 Move log10_2_significand to format-inl.h
d9ebc4e82 Add a function to get sign char
c00eb4f4c Add missing inline
25af02f21 positive -> nonnegative (#2493)
67cb2dad3 Optimize %F in tm formatting
1aa98f8b9 Eliminate double copying in vformat_to_n (#2489)
a58c13382 Improve code_point_length codegen on older gcc
aeee70a81 Remove unnecessary cast
c771ba361 Fix build for the clang-10 / libstdc++-9 couple (#2491)
ab6e2272c Clarify shifts encoding
e4728409e Use throw_format_error in more places to reduce bloat
e3ebf366a Inline padding shifts
894faf3fe Refactor presentation types
4eb97fa4e Reduce code bloat
6b55c8325 is_const_formattable -> has_const_formatter
2fe94ad7e Make specifiers support in tuple_join an opt-in
3940de595 thousands -> group_digits
c4d0f96a6 Implement format specs in fmt::thousands
3b9c44268 Implement thousands separators without locales
08f98c7fa Simplify get_arg_index_by_name
a151f955a Remove FMT_OVERRIDE
42a225cbd Remove redundand final
bf20d1990 Simplify the core API
fc0884037 Move FMT_GCC_VISIBILITY_HIDDEN to format.h
1aeed2dbc Require inline namespaces
799bea473 Remove FMT_HAS_GXX_CXX11
60cd5ea3f Add support for more formattable types in ranges
4fd9a00f3 Simplify ostream interface
568156389 Cleanup ostream interface
20931baf1 Disable fallback_formatter for arrays
d58d19ba3 Fix an odr violation in ranges.h (#2483)
ee0659f8b Fix formatting of abstract classes via ostream
8029bf955 Fix copy_str performance (#2477)
2520f410c Workaround for #2478 (#2482)
ee63f5f04 Workaround to MSVC bug (#2474) (#2476)
1aaf72fb6 Add an example to fmt::runtime
c1313c205 Clarify that format_to[_n] do not append a terminating null
cb0f177c3 Improve docs
71677e520 Improve docs
4db572352 add fuzzers for chrono timepoint and localtime,gmtime (#2469)
dc7f3ef2b Fix header name
419ba86a9 Improve docs
6a5b4d5fa Document format_string
2599163b8 Document format_string
8ef22f774 Update docs
c0c4d1ada Update docs
729a44e67 Depreate strtod and remove problematic tests
74c111896 Apply force inline
596508a92 Cleanup
043e3b342 Remove static_assert from arg_mapper
8b0cb944d Fix error reporting when mixing character types
117fc6707 CI: replace g++ C++20 build to test FP formatting at compile-time
c79a3841e make detail::fp and detail::bigit constexpr
5888de9f3 make detail::make_checked() constexpr
04b4b69b1 make detail::bit_cast() constexpr with C++20
fd34a3d24 make detail::basic_memory_buffer constexpr with C++20
6d597e39c Fix overload ambiguity in arg_mapper
b9ce56d93 Improve comments
f889e52a1 Improve error reporting
34caecd6b Use consistent initialization style
a44c8f651 reimplement `formatter<tuple_join_view>` (#2457)
4b8bda25c Fix 2462
6b5e6119e set clang in one place
7af1dc1d2 fix UB in fuzzer common (memcpy on nullptr)
e77686f7a clang format
2207ea0b3 More escaping
a212ff757 Escape invalid code points
a76031e11 check -> is_printable
a7f280765 Improve naming
07d033ecb Fix is_printable
cdb4299ac Add Unicode support to is_printable
7df2c82a8 Rewrite printable.py codegen to emit C++
6cf90d7ce Add script license and fix python version
2f1ad8ed3 Add printable codegen from Rust
371d8e2ee Escape Unicode
6397095ca More escaping
f69a57253 Don't overescape wide strings
11b07a56b We should escape
b559cfd4c Implement basic escaping
11d49491c Handle global locale
6ea6cf946 Add decimal separator support to float
9730a2af0 Update ChangeLog.rst
c2ed5f686 Update ChangeLog.rst
7b66e72e2 Use builtin intrinsics on intel (#2450)
d57b2a652 Suppress a warning
bdfbd794e Cleanup begin/end usage
111de881f Don't copy non-const-iterable ranges
d6e882ed8 Undo the move because the doc is not a GH template
f488eed10 Resolve default constructor error in Xcode 7.2.1 and 8.2.1
652c3653b Move CONTRIBUTING.md to .github
fb19faa31 Improves README with svg badge (#2446)
07211701f Disable the -Wstringop-overflow warning from GCC 7 (#2442)
bba0a9d96 Make flush public
f1794a885 Switch to threadsafe death test style
0544a2279 Exclude fallback functions when FMT_BUILTIN_CLZ(LL) is not defined (#2434)
5c222f056 Add support for nonconst formattable types
3def950b8 Set FMT_CAN_MODULE=OFF for MSVC 19.29.30035+
63fe2d5bd Add copy constructor for dynamic_format_arg_store, and test
561834650 Improve digit count
f20f50368 Replace `throw` with `FMT_THROW` (#2427)
00235d8a9 fix module test odr violations (#2414)
2038bf618 Update format_to usage
e41ac1f87 Don't use deprecated API in docs
8465869d7 Move ignore_unused to detail
3d53d1539 Warning removals in test code (#2399)
20e4ef8b4 Pass significand_size by value
c4a3c2342 Refactor locale handling
7a0d30175 Update README.rst
f2b03facd Include test sources to pick up functions and classes from the module rather than from the non-modular library which is baked into the `test-main` library. (#2356)
02ad5e11d Add faint, blink, reverse and conceal to the emphases (#2394)
d141cdbeb Update version
cfc05e05f Bump version
8ea312633 Update changelog
e461f3dbb Minor consitency and comment tweaks
54014e42e silence warning C4100 on MSVC 2019 when exceptions are disabled (#2397)
3e7a29cc9 Workaround clang/gcc incompatibility
00a57a9f8 Update changelog
1d7384530 Add missing presentation type checks for std::string (#2402)
889bbf27a Fix missing std::get overload in MSVC (#2407)
5f8473914 Remove outdated apidoc
785908ee3 Fix warnings
fbb70eec5 suppress unused variable warnings (#2381)
002bb759f Remove unneeded `num_result_bigits` decrement
a3f762c5a [doc] Minor: fix ``code``.
c3c27e5ab Fix MSVC warning C4819
c6b1f181a Fix docs
94564b058 Fix docs
0fc73a2a8 Merge branch 'master' of github.com:fmtlib/fmt
3156fcf5f Switch to older breathe version
f85fb9fdf Adjust definition for FMT_HAS_INCLUDE
0bc3d664e Fix docs
e5c46e13e Fix docs: breathe 18 and earlier corrupts trailing return type
49a3b58c8 Specify size for static data arrays
d0c8d45a2 apt update before install
c9a10631c format: do not use udl_{arg,formatter} return types when UDL is not in use
3bd806f12 Eliminate intel compiler warning
fd16bcb20 Fix bug in cmake join function
5221242f6 Instruct msvc to report the _true_ value in `__cplusplus` and force _full_ C++ conformance
31a5f0d39 Bump version in inline namespace
102a4d492 Bump version in inline namespace
f68508b6c Update ChangeLog.rst

git-subtree-dir: externals/fmt
git-subtree-split: b6f4ceaed0a0a24ccf575fab6c56dd50ccf6f1a9

.github/workflows/doc.yml

@@ -12,6 +12,7 @@ jobs:
 
     - name: Create Build Environment
       run: |
+        sudo apt update
         sudo apt install doxygen python3-virtualenv
         sudo npm install -g less clean-css
         cmake -E make_directory ${{runner.workspace}}/build

.github/workflows/linux.yml

@@ -24,10 +24,11 @@ jobs:
             build_type: Debug
             std: 17
             os: ubuntu-18.04
-          - cxx: g++-10
+          - cxx: g++-11
             build_type: Debug
             std: 20
             os: ubuntu-20.04
+            install: sudo apt install g++-11
           - cxx: clang++-9
             build_type: Debug
             fuzz: -DFMT_FUZZ=ON -DFMT_FUZZ_LINKMAIN=ON

CMakeLists.txt

@@ -17,7 +17,7 @@ endif ()
 
 # Joins arguments and places the results in ${result_var}.
 function(join result_var)
-  set(result )
+  set(result "")
   foreach (arg ${ARGN})
     set(result "${result}${arg}")
   endforeach ()
@@ -81,12 +81,13 @@ option(FMT_FUZZ "Generate the fuzz target." OFF)
 option(FMT_CUDA_TEST "Generate the cuda-test target." OFF)
 option(FMT_OS "Include core requiring OS (Windows/Posix) " ON)
 option(FMT_MODULE "Build a module instead of a traditional library." OFF)
+option(FMT_SYSTEM_HEADERS "Expose headers with marking them as system." OFF)
 
 set(FMT_CAN_MODULE OFF)
 if (CMAKE_CXX_STANDARD GREATER 17 AND
     # msvc 16.10-pre4
     MSVC AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 19.29.30035)
-  set(FMT_CAN_MODULE ON)
+  set(FMT_CAN_MODULE OFF)
 endif ()
 if (NOT FMT_CAN_MODULE)
   set(FMT_MODULE OFF)
@@ -96,6 +97,10 @@ if (FMT_TEST AND FMT_MODULE)
   # The tests require {fmt} to be compiled as traditional library
   message(STATUS "Testing is incompatible with build mode 'module'.")
 endif ()
+set(FMT_SYSTEM_HEADERS_ATTRIBUTE "")
+if (FMT_SYSTEM_HEADERS)
+  set(FMT_SYSTEM_HEADERS_ATTRIBUTE SYSTEM)
+endif ()
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)
@@ -151,7 +156,7 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
       -Wcast-align
       -Wctor-dtor-privacy -Wdisabled-optimization
       -Winvalid-pch -Woverloaded-virtual
-      -Wconversion -Wswitch-enum -Wundef
+      -Wconversion -Wundef
       -Wno-ctor-dtor-privacy -Wno-format-nonliteral)
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
@@ -244,7 +249,7 @@ if (HAVE_STRTOD_L)
 endif ()
 
 if (MINGW)
-  check_cxx_compiler_flag("Wa,-mbig-obj" FMT_HAS_MBIG_OBJ)
+  check_cxx_compiler_flag("-Wa,-mbig-obj" FMT_HAS_MBIG_OBJ)
   if (${FMT_HAS_MBIG_OBJ})
     target_compile_options(fmt PUBLIC "-Wa,-mbig-obj")
   endif()
@@ -262,7 +267,7 @@ endif ()
 
 target_compile_features(fmt INTERFACE ${FMT_REQUIRED_FEATURES})
 
-target_include_directories(fmt PUBLIC
+target_include_directories(fmt ${FMT_SYSTEM_HEADERS_ATTRIBUTE} PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 
@@ -298,7 +303,7 @@ add_library(fmt::fmt-header-only ALIAS fmt-header-only)
 target_compile_definitions(fmt-header-only INTERFACE FMT_HEADER_ONLY=1)
 target_compile_features(fmt-header-only INTERFACE ${FMT_REQUIRED_FEATURES})
 
-target_include_directories(fmt-header-only INTERFACE
+target_include_directories(fmt-header-only ${FMT_SYSTEM_HEADERS_ATTRIBUTE} INTERFACE
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 

ChangeLog.rst

@@ -1,7 +1,427 @@
+8.1.1 - 2022-01-06
+------------------
+
+* Restored ABI compatibility with version 8.0.x
+  (`#2695 <https://github.com/fmtlib/fmt/issues/2695>`_,
+  `#2696 <https://github.com/fmtlib/fmt/pull/2696>`_).
+  Thanks `@saraedum (Julian Rüth) <https://github.com/saraedum>`_.
+
+* Fixed chorno formatting on big endian systems
+  (`#2698 <https://github.com/fmtlib/fmt/issues/2698>`_,
+  `#2699 <https://github.com/fmtlib/fmt/pull/2699>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_ and
+  `@xvitaly (Vitaly Zaitsev) <https://github.com/xvitaly>`_.
+
+* Fixed a linkage error with mingw
+  (`#2691 <https://github.com/fmtlib/fmt/issues/2691>`_,
+  `#2692 <https://github.com/fmtlib/fmt/pull/2692>`_).
+  Thanks `@rbberger (Richard Berger) <https://github.com/rbberger>`_.
+
+8.1.0 - 2022-01-02
+------------------
+
+* Optimized chrono formatting
+  (`#2500 <https://github.com/fmtlib/fmt/pull/2500>`_,
+  `#2537 <https://github.com/fmtlib/fmt/pull/2537>`_,
+  `#2541 <https://github.com/fmtlib/fmt/issues/2541>`_,
+  `#2544 <https://github.com/fmtlib/fmt/pull/2544>`_,
+  `#2550 <https://github.com/fmtlib/fmt/pull/2550>`_,
+  `#2551 <https://github.com/fmtlib/fmt/pull/2551>`_,
+  `#2576 <https://github.com/fmtlib/fmt/pull/2576>`_,
+  `#2577 <https://github.com/fmtlib/fmt/issues/2577>`_,
+  `#2586 <https://github.com/fmtlib/fmt/pull/2586>`_,
+  `#2591 <https://github.com/fmtlib/fmt/pull/2591>`_,
+  `#2594 <https://github.com/fmtlib/fmt/pull/2594>`_,
+  `#2602 <https://github.com/fmtlib/fmt/pull/2602>`_,
+  `#2617 <https://github.com/fmtlib/fmt/pull/2617>`_,
+  `#2628 <https://github.com/fmtlib/fmt/issues/2628>`_,
+  `#2633 <https://github.com/fmtlib/fmt/pull/2633>`_,
+  `#2670 <https://github.com/fmtlib/fmt/issues/2670>`_,
+  `#2671 <https://github.com/fmtlib/fmt/pull/2671>`_).
+
+  Processing of some specifiers such as ``%z`` and ``%Y`` is now up to 10-20
+  times faster, for example on GCC 11 with libstdc++::
+
+    ----------------------------------------------------------------------------
+    Benchmark                                  Before             After
+    ----------------------------------------------------------------------------
+    FMTFormatter_z                             261 ns             26.3 ns
+    FMTFormatterCompile_z                      246 ns             11.6 ns
+    FMTFormatter_Y                             263 ns             26.1 ns
+    FMTFormatterCompile_Y                      244 ns             10.5 ns
+    ----------------------------------------------------------------------------
+
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_ and
+  `@toughengineer (Pavel Novikov) <https://github.com/toughengineer>`_.
+
+* Implemented subsecond formatting for chrono durations
+  (`#2623 <https://github.com/fmtlib/fmt/pull/2623>`_).
+  For example (`godbolt <https://godbolt.org/z/es7vWTETe>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       fmt::print("{:%S}", std::chrono::milliseconds(1234));
+     }
+
+  prints "01.234".
+
+  Thanks `@matrackif <https://github.com/matrackif>`_.
+
+* Fixed handling of precision 0 when formatting chrono durations
+  (`#2587 <https://github.com/fmtlib/fmt/issues/2587>`_,
+  `#2588 <https://github.com/fmtlib/fmt/pull/2588>`_).
+  Thanks `@lukester1975 <https://github.com/lukester1975>`_.
+
+* Fixed an overflow on invalid inputs in the ``tm`` formatter
+  (`#2564 <https://github.com/fmtlib/fmt/pull/2564>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Added ``fmt::group_digits`` that formats integers with a non-localized digit
+  separator (comma) for groups of three digits.
+  For example (`godbolt <https://godbolt.org/z/TxGxG9Poq>`__):
+
+  .. code:: c++
+
+     #include <fmt/format.h>
+
+     int main() {
+       fmt::print("{} dollars", fmt::group_digits(1000000));
+     }
+
+  prints "1,000,000 dollars".
+
+* Added support for faint, conceal, reverse and blink text styles
+  (`#2394 <https://github.com/fmtlib/fmt/pull/2394>`_):
+
+  https://user-images.githubusercontent.com/576385/147710227-c68f5317-f8fa-42c3-9123-7c4ba3c398cb.mp4
+
+  Thanks `@benit8 (Benoît Lormeau) <https://github.com/benit8>`_ and
+  `@data-man (Dmitry Atamanov) <https://github.com/data-man>`_.
+
+* Added experimental support for compile-time floating point formatting
+  (`#2426 <https://github.com/fmtlib/fmt/pull/2426>`_,
+  `#2470 <https://github.com/fmtlib/fmt/pull/2470>`_).
+  It is currently limited to the header-only mode.
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added UDL-based named argument support to compile-time format string checks
+  (`#2640 <https://github.com/fmtlib/fmt/issues/2640>`_,
+  `#2649 <https://github.com/fmtlib/fmt/pull/2649>`_).
+  For example (`godbolt <https://godbolt.org/z/ohGbbvonv>`__):
+
+  .. code:: c++
+
+     #include <fmt/format.h>
+
+     int main() {
+       using namespace fmt::literals;
+       fmt::print("{answer:s}", "answer"_a=42);
+     }
+
+  gives a compile-time error on compilers with C++20 ``consteval`` and non-type
+  template parameter support (gcc 10+) because ``s`` is not a valid format
+  specifier for an integer.
+
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Implemented escaping of string range elements.
+  For example (`godbolt <https://godbolt.org/z/rKvM1vKf3>`__):
+
+  .. code:: c++
+
+     #include <fmt/ranges.h>
+     #include <vector>
+
+     int main() {
+       fmt::print("{}", std::vector<std::string>{"\naan"});
+     }
+
+  is now printed as::
+
+    ["\naan"]
+
+  instead of::
+  
+    ["
+    aan"]
+
+* Switched to JSON-like representation of maps and sets for consistency with
+  Python's ``str.format``.
+  For example (`godbolt <https://godbolt.org/z/seKjoY9W5>`__):
+
+  .. code:: c++
+
+     #include <fmt/ranges.h>
+     #include <map>
+
+     int main() {
+       fmt::print("{}", std::map<std::string, int>{{"answer", 42}});
+     }
+
+  is now printed as::
+
+    {"answer": 42}
+
+* Extended ``fmt::join`` to support C++20-only ranges
+  (`#2549 <https://github.com/fmtlib/fmt/pull/2549>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Optimized handling of non-const-iterable ranges and implemented initial
+  support for non-const-formattable types.
+
+* Disabled implicit conversions of scoped enums to integers that was
+  accidentally introduced in earlier versions
+  (`#1841 <https://github.com/fmtlib/fmt/pull/1841>`_).
+
+* Deprecated implicit conversion of ``[const] signed char*`` and 
+  ``[const] unsigned char*`` to C strings.
+
+* Deprecated ``_format``, a legacy UDL-based format API
+  (`#2646 <https://github.com/fmtlib/fmt/pull/2646>`_).
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Marked ``format``, ``formatted_size`` and ``to_string`` as ``[[nodiscard]]``
+  (`#2612 <https://github.com/fmtlib/fmt/pull/2612>`_).
+  `@0x8000-0000 (Florin Iucha) <https://github.com/0x8000-0000>`_.
+
+* Added missing diagnostic when trying to format function and member pointers
+  as well as objects convertible to pointers which is explicitly disallowed
+  (`#2598 <https://github.com/fmtlib/fmt/issues/2598>`_,
+  `#2609 <https://github.com/fmtlib/fmt/pull/2609>`_,
+  `#2610 <https://github.com/fmtlib/fmt/pull/2610>`_).
+  Thanks `@AlexGuteniev (Alex Guteniev) <https://github.com/AlexGuteniev>`_.
+
+* Optimized writing to a contiguous buffer with ``format_to_n``
+  (`#2489 <https://github.com/fmtlib/fmt/pull/2489>`_).
+  Thanks `@Roman-Koshelev <https://github.com/Roman-Koshelev>`_.
+
+* Optimized writing to non-``char`` buffers
+  (`#2477 <https://github.com/fmtlib/fmt/pull/2477>`_).
+  Thanks `@Roman-Koshelev <https://github.com/Roman-Koshelev>`_.
+
+* Decimal point is now localized when using the ``L`` specifier.
+
+* Improved floating point formatter implementation
+  (`#2498 <https://github.com/fmtlib/fmt/pull/2498>`_,
+  `#2499 <https://github.com/fmtlib/fmt/pull/2499>`_).
+  Thanks `@Roman-Koshelev <https://github.com/Roman-Koshelev>`_.
+
+* Fixed handling of very large precision in fixed format
+  (`#2616 <https://github.com/fmtlib/fmt/pull/2616>`_).
+
+* Made a table of cached powers used in FP formatting static
+  (`#2509 <https://github.com/fmtlib/fmt/pull/2509>`_).
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Resolved a lookup ambiguity with C++20 format-related functions due to ADL
+  (`#2639 <https://github.com/fmtlib/fmt/issues/2639>`_,
+  `#2641 <https://github.com/fmtlib/fmt/pull/2641>`_).
+  Thanks `@mkurdej (Marek Kurdej) <https://github.com/mkurdej>`_.
+
+* Removed unnecessary inline namespace qualification
+  (`#2642 <https://github.com/fmtlib/fmt/issues/2642>`_,
+  `#2643 <https://github.com/fmtlib/fmt/pull/2643>`_).
+  Thanks `@mkurdej (Marek Kurdej) <https://github.com/mkurdej>`_.
+
+* Implemented argument forwarding in ``format_to_n``
+  (`#2462 <https://github.com/fmtlib/fmt/issues/2462>`_,
+  `#2463 <https://github.com/fmtlib/fmt/pull/2463>`_).
+  Thanks `@owent (WenTao Ou) <https://github.com/owent>`_.
+
+* Fixed handling of implicit conversions in ``fmt::to_string`` and format string
+  compilation (`#2565 <https://github.com/fmtlib/fmt/issues/2565>`_).
+
+* Changed the default access mode of files created by ``fmt::output_file`` to
+  ``-rw-r--r--`` for consistency with ``fopen``
+  (`#2530 <https://github.com/fmtlib/fmt/issues/2530>`_).
+
+* Make ``fmt::ostream::flush`` public
+  (`#2435 <https://github.com/fmtlib/fmt/issues/2435>`_).
+
+* Improved C++14/17 attribute detection
+  (`#2615 <https://github.com/fmtlib/fmt/pull/2615>`_).
+  Thanks `@AlexGuteniev (Alex Guteniev) <https://github.com/AlexGuteniev>`_.
+
+* Improved ``consteval`` detection for MSVC
+  (`#2559 <https://github.com/fmtlib/fmt/pull/2559>`_).
+  Thanks `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_.
+
+* Improved documentation
+  (`#2406 <https://github.com/fmtlib/fmt/issues/2406>`_,
+  `#2446 <https://github.com/fmtlib/fmt/pull/2446>`_,
+  `#2493 <https://github.com/fmtlib/fmt/issues/2493>`_,
+  `#2513 <https://github.com/fmtlib/fmt/issues/2513>`_,
+  `#2515 <https://github.com/fmtlib/fmt/pull/2515>`_,
+  `#2522 <https://github.com/fmtlib/fmt/issues/2522>`_,
+  `#2562 <https://github.com/fmtlib/fmt/pull/2562>`_,
+  `#2575 <https://github.com/fmtlib/fmt/pull/2575>`_,
+  `#2606 <https://github.com/fmtlib/fmt/pull/2606>`_,
+  `#2620 <https://github.com/fmtlib/fmt/pull/2620>`_,
+  `#2676 <https://github.com/fmtlib/fmt/issues/2676>`_).
+  Thanks `@sobolevn (Nikita Sobolev) <https://github.com/sobolevn>`_,
+  `@UnePierre (Max FERGER) <https://github.com/UnePierre>`_,
+  `@zhsj <https://github.com/zhsj>`_,
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_,
+  `@ericcurtin (Eric Curtin) <https://github.com/ericcurtin>`_,
+  `@Lounarok <https://github.com/Lounarok>`_.
+
+* Improved fuzzers and added a fuzzer for chrono timepoint formatting
+  (`#2461 <https://github.com/fmtlib/fmt/pull/2461>`_,
+  `#2469 <https://github.com/fmtlib/fmt/pull/2469>`_).
+  `@pauldreik (Paul Dreik) <https://github.com/pauldreik>`_,
+
+* Added the ``FMT_SYSTEM_HEADERS`` CMake option setting which marks {fmt}'s
+  headers as system. It can be used to suppress warnings
+  (`#2644 <https://github.com/fmtlib/fmt/issues/2644>`_,
+  `#2651 <https://github.com/fmtlib/fmt/pull/2651>`_).
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added the Bazel build system support
+  (`#2505 <https://github.com/fmtlib/fmt/pull/2505>`_,
+  `#2516 <https://github.com/fmtlib/fmt/pull/2516>`_).
+  Thanks `@Vertexwahn <https://github.com/Vertexwahn>`_.
+
+* Improved build configuration and tests
+  (`#2437 <https://github.com/fmtlib/fmt/issues/2437>`_,
+  `#2558 <https://github.com/fmtlib/fmt/pull/2558>`_,
+  `#2648 <https://github.com/fmtlib/fmt/pull/2648>`_,
+  `#2650 <https://github.com/fmtlib/fmt/pull/2650>`_,
+  `#2663 <https://github.com/fmtlib/fmt/pull/2663>`_,
+  `#2677 <https://github.com/fmtlib/fmt/pull/2677>`_).
+  Thanks `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_,
+  `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_,
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Fixed various warnings and compilation issues
+  (`#2353 <https://github.com/fmtlib/fmt/pull/2353>`_,
+  `#2356 <https://github.com/fmtlib/fmt/pull/2356>`_,
+  `#2399 <https://github.com/fmtlib/fmt/pull/2399>`_,
+  `#2408 <https://github.com/fmtlib/fmt/issues/2408>`_,
+  `#2414 <https://github.com/fmtlib/fmt/pull/2414>`_,
+  `#2427 <https://github.com/fmtlib/fmt/pull/2427>`_,
+  `#2432 <https://github.com/fmtlib/fmt/pull/2432>`_,
+  `#2442 <https://github.com/fmtlib/fmt/pull/2442>`_,
+  `#2434 <https://github.com/fmtlib/fmt/pull/2434>`_,
+  `#2439 <https://github.com/fmtlib/fmt/issues/2439>`_,
+  `#2447 <https://github.com/fmtlib/fmt/pull/2447>`_,
+  `#2450 <https://github.com/fmtlib/fmt/pull/2450>`_,
+  `#2455 <https://github.com/fmtlib/fmt/issues/2455>`_,
+  `#2465 <https://github.com/fmtlib/fmt/issues/2465>`_,
+  `#2472 <https://github.com/fmtlib/fmt/issues/2472>`_,
+  `#2474 <https://github.com/fmtlib/fmt/issues/2474>`_,
+  `#2476 <https://github.com/fmtlib/fmt/pull/2476>`_,
+  `#2478 <https://github.com/fmtlib/fmt/issues/2478>`_,
+  `#2479 <https://github.com/fmtlib/fmt/issues/2479>`_,
+  `#2481 <https://github.com/fmtlib/fmt/issues/2481>`_,
+  `#2482 <https://github.com/fmtlib/fmt/pull/2482>`_,
+  `#2483 <https://github.com/fmtlib/fmt/pull/2483>`_,
+  `#2490 <https://github.com/fmtlib/fmt/issues/2490>`_,
+  `#2491 <https://github.com/fmtlib/fmt/pull/2491>`_,
+  `#2510 <https://github.com/fmtlib/fmt/pull/2510>`_,
+  `#2518 <https://github.com/fmtlib/fmt/pull/2518>`_,
+  `#2528 <https://github.com/fmtlib/fmt/issues/2528>`_,
+  `#2529 <https://github.com/fmtlib/fmt/pull/2529>`_,
+  `#2539 <https://github.com/fmtlib/fmt/pull/2539>`_,
+  `#2540 <https://github.com/fmtlib/fmt/issues/2540>`_,
+  `#2545 <https://github.com/fmtlib/fmt/pull/2545>`_,
+  `#2555 <https://github.com/fmtlib/fmt/pull/2555>`_,
+  `#2557 <https://github.com/fmtlib/fmt/issues/2557>`_,
+  `#2570 <https://github.com/fmtlib/fmt/issues/2570>`_,
+  `#2573 <https://github.com/fmtlib/fmt/pull/2573>`_,
+  `#2582 <https://github.com/fmtlib/fmt/pull/2582>`_,
+  `#2605 <https://github.com/fmtlib/fmt/issues/2605>`_,
+  `#2611 <https://github.com/fmtlib/fmt/pull/2611>`_,
+  `#2647 <https://github.com/fmtlib/fmt/pull/2647>`_,
+  `#2627 <https://github.com/fmtlib/fmt/issues/2627>`_,
+  `#2630 <https://github.com/fmtlib/fmt/pull/2630>`_,
+  `#2635 <https://github.com/fmtlib/fmt/issues/2635>`_,
+  `#2638 <https://github.com/fmtlib/fmt/issues/2638>`_,
+  `#2653 <https://github.com/fmtlib/fmt/issues/2653>`_,
+  `#2654 <https://github.com/fmtlib/fmt/issues/2654>`_,
+  `#2661 <https://github.com/fmtlib/fmt/issues/2661>`_,
+  `#2664 <https://github.com/fmtlib/fmt/pull/2664>`_,
+  `#2684 <https://github.com/fmtlib/fmt/pull/2684>`_).
+  Thanks `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_,
+  `@mwinterb <https://github.com/mwinterb>`_,
+  `@cdacamar (Cameron DaCamara) <https://github.com/cdacamar>`_,
+  `@TrebledJ (Johnathan) <https://github.com/TrebledJ>`_,
+  `@bodomartin (brm) <https://github.com/bodomartin>`_,
+  `@cquammen (Cory Quammen) <https://github.com/cquammen>`_,
+  `@white238 (Chris White) <https://github.com/white238>`_,
+  `@mmarkeloff (Max) <https://github.com/mmarkeloff>`_,
+  `@palacaze (Pierre-Antoine Lacaze) <https://github.com/palacaze>`_,
+  `@jcelerier (Jean-Michaël Celerier) <https://github.com/jcelerier>`_,
+  `@mborn-adi (Mathias Born) <https://github.com/mborn-adi>`_,
+  `@BrukerJWD (Jonathan W) <https://github.com/BrukerJWD>`_,
+  `@spyridon97 (Spiros Tsalikis) <https://github.com/spyridon97>`_,
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_,
+  `@oliverlee (Oliver Lee) <https://github.com/oliverlee>`_,
+  `@joshessman-llnl (Josh Essman) <https://github.com/joshessman-llnl>`_,
+  `@akohlmey (Axel Kohlmeyer) <https://github.com/akohlmey>`_,
+  `@timkalu <https://github.com/timkalu>`_,
+  `@olupton (Olli Lupton) <https://github.com/olupton>`_,
+  `@Acretock <https://github.com/Acretock>`_,
+  `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_,
+  `@andrewcorrigan (Andrew Corrigan) <https://github.com/andrewcorrigan>`_,
+  `@lucpelletier <https://github.com/lucpelletier>`_,
+  `@HazardyKnusperkeks (Björn Schäpers) <https://github.com/HazardyKnusperkeks>`_.
+
+8.0.1 - 2021-07-02
+------------------
+
+* Fixed the version number in the inline namespace
+  (`#2374 <https://github.com/fmtlib/fmt/issues/2374>`_).
+
+* Added a missing presentation type check for ``std::string``
+  (`#2402 <https://github.com/fmtlib/fmt/issues/2402>`_).
+
+* Fixed a linkage error when mixing code built with clang and gcc
+  (`#2377 <https://github.com/fmtlib/fmt/issues/2377>`_).
+
+* Fixed documentation issues
+  (`#2396 <https://github.com/fmtlib/fmt/pull/2396>`_,
+  `#2403 <https://github.com/fmtlib/fmt/issues/2403>`_,
+  `#2406 <https://github.com/fmtlib/fmt/issues/2406>`_).
+  Thanks `@mkurdej (Marek Kurdej) <https://github.com/mkurdej>`_.
+
+* Removed dead code in FP formatter (
+  `#2398 <https://github.com/fmtlib/fmt/pull/2398>`_).
+  Thanks `@javierhonduco (Javier Honduvilla Coto)
+  <https://github.com/javierhonduco>`_.
+
+* Fixed various warnings and compilation issues
+  (`#2351 <https://github.com/fmtlib/fmt/issues/2351>`_,
+  `#2359 <https://github.com/fmtlib/fmt/issues/2359>`_,
+  `#2365 <https://github.com/fmtlib/fmt/pull/2365>`_,
+  `#2368 <https://github.com/fmtlib/fmt/issues/2368>`_,
+  `#2370 <https://github.com/fmtlib/fmt/pull/2370>`_,
+  `#2376 <https://github.com/fmtlib/fmt/pull/2376>`_,
+  `#2381 <https://github.com/fmtlib/fmt/pull/2381>`_,
+  `#2382 <https://github.com/fmtlib/fmt/pull/2382>`_,
+  `#2386 <https://github.com/fmtlib/fmt/issues/2386>`_,
+  `#2389 <https://github.com/fmtlib/fmt/pull/2389>`_,
+  `#2395 <https://github.com/fmtlib/fmt/pull/2395>`_,
+  `#2397 <https://github.com/fmtlib/fmt/pull/2397>`_,
+  `#2400 <https://github.com/fmtlib/fmt/issues/2400>`_,
+  `#2401 <https://github.com/fmtlib/fmt/issues/2401>`_,
+  `#2407 <https://github.com/fmtlib/fmt/pull/2407>`_).
+  Thanks `@zx2c4 (Jason A. Donenfeld) <https://github.com/zx2c4>`_,
+  `@AidanSun05 (Aidan Sun) <https://github.com/AidanSun05>`_,
+  `@mattiasljungstrom (Mattias Ljungström)
+  <https://github.com/mattiasljungstrom>`_,
+  `@joemmett (Jonathan Emmett) <https://github.com/joemmett>`_,
+  `@erengy (Eren Okka) <https://github.com/erengy>`_,
+  `@patlkli (Patrick Geltinger) <https://github.com/patlkli>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
 8.0.0 - 2021-06-21
 ------------------
 
-* Enabled compile-time format string check by default.
+* Enabled compile-time format string checks by default.
   For example (`godbolt <https://godbolt.org/z/sMxcohGjz>`__):
 
   .. code:: c++
@@ -232,6 +652,9 @@
   This doesn't introduce a dependency on ``<locale>`` so there is virtually no
   compile time effect.
 
+* Deprecated an undocumented ``format_to`` overload that takes
+  ``basic_memory_buffer``.
+
 * Made parameter order in ``vformat_to`` consistent with ``format_to``
   (`#2327 <https://github.com/fmtlib/fmt/issues/2327>`_).
 
@@ -301,9 +724,9 @@
   ``make_format_to_n_args``. They have been replaced with ``format_context``,
   ``format_args` and ``make_format_args`` respectively.
 
-* Moved ``wchar_t``-specific functions and types to ``fmt/wchar.h``.
+* Moved ``wchar_t``-specific functions and types to ``fmt/xchar.h``.
-  You can define ``FMT_DEPRECATED_INCLUDE_WCHAR`` to automatically include
+  You can define ``FMT_DEPRECATED_INCLUDE_XCHAR`` to automatically include
-  ``fmt/wchar.h`` from ``fmt/format.h`` but this will be disabled in the next
+  ``fmt/xchar.h`` from ``fmt/format.h`` but this will be disabled in the next
   major release.
 
 * Fixed handling of the ``'+'`` specifier in localized formatting
@@ -338,6 +761,9 @@
 
   Thanks `@mikecrowe (Mike Crowe) <https://github.com/mikecrowe>`_.
 
+* The undocumented support for specializing ``formatter`` for pointer types
+  has been removed.
+
 * Fixed ``fmt::formatted_size`` with format string compilation
   (`#2141 <https://github.com/fmtlib/fmt/pull/2141>`_,
   `#2161 <https://github.com/fmtlib/fmt/pull/2161>`_).
@@ -510,13 +936,13 @@
   `#2067 <https://github.com/fmtlib/fmt/pull/2067>`_,
   `#2068 <https://github.com/fmtlib/fmt/pull/2068>`_,
   `#2073 <https://github.com/fmtlib/fmt/pull/2073>`_,
-  `#2103 <https://github.com/fmtlib/fmt/issues/2103>`_
+  `#2103 <https://github.com/fmtlib/fmt/issues/2103>`_,
-  `#2105 <https://github.com/fmtlib/fmt/issues/2105>`_
+  `#2105 <https://github.com/fmtlib/fmt/issues/2105>`_,
   `#2106 <https://github.com/fmtlib/fmt/pull/2106>`_,
   `#2107 <https://github.com/fmtlib/fmt/pull/2107>`_,
-  `#2116 <https://github.com/fmtlib/fmt/issues/2116>`_
+  `#2116 <https://github.com/fmtlib/fmt/issues/2116>`_,
   `#2117 <https://github.com/fmtlib/fmt/pull/2117>`_,
-  `#2118 <https://github.com/fmtlib/fmt/issues/2118>`_
+  `#2118 <https://github.com/fmtlib/fmt/issues/2118>`_,
   `#2119 <https://github.com/fmtlib/fmt/pull/2119>`_,
   `#2127 <https://github.com/fmtlib/fmt/issues/2127>`_,
   `#2128 <https://github.com/fmtlib/fmt/pull/2128>`_,
@@ -589,7 +1015,7 @@
   `@yeswalrus (Walter Gray) <https://github.com/yeswalrus>`_,
   `@Finkman <https://github.com/Finkman>`_,
   `@HazardyKnusperkeks (Björn Schäpers) <https://github.com/HazardyKnusperkeks>`_,
-  `@dkavolis (Daumantas Kavolis) <https://github.com/dkavolis>`_
+  `@dkavolis (Daumantas Kavolis) <https://github.com/dkavolis>`_,
   `@concatime (Issam Maghni) <https://github.com/concatime>`_,
   `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
   `@summivox (Yin Zhong) <https://github.com/summivox>`_,
@@ -1046,7 +1472,7 @@
   `#1912 <https://github.com/fmtlib/fmt/issues/1912>`_,
   `#1928 <https://github.com/fmtlib/fmt/issues/1928>`_,
   `#1929 <https://github.com/fmtlib/fmt/pull/1929>`_,
-  `#1935 <https://github.com/fmtlib/fmt/issues/1935>`_
+  `#1935 <https://github.com/fmtlib/fmt/issues/1935>`_,
   `#1937 <https://github.com/fmtlib/fmt/pull/1937>`_,
   `#1942 <https://github.com/fmtlib/fmt/pull/1942>`_,
   `#1949 <https://github.com/fmtlib/fmt/issues/1949>`_).

README.rst

@@ -10,7 +10,7 @@
 .. image:: https://github.com/fmtlib/fmt/workflows/windows/badge.svg
    :target: https://github.com/fmtlib/fmt/actions?query=workflow%3Awindows
 
-.. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v
+.. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v?svg=true
    :target: https://ci.appveyor.com/project/vitaut/fmt
 
 .. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/fmt.svg
@@ -143,10 +143,10 @@ Output::
 
 .. code:: c++
 
-    std::string s = fmt::format(FMT_STRING("{:d}"), "I am not a number");
+    std::string s = fmt::format("{:d}", "I am not a number");
 
-This gives a compile-time error because ``d`` is an invalid format specifier for
+This gives a compile-time error in C++20 because ``d`` is an invalid format
-a string.
+specifier for a string.
 
 **Write a file from a single thread**
 
@@ -205,7 +205,7 @@ The above results were generated by building ``tinyformat_test.cpp`` on macOS
 best of three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
 or equivalent is filled 2,000,000 times with output sent to ``/dev/null``; for
 further details refer to the `source
-<https://github.com/fmtlib/format-benchmark/blob/master/tinyformat_test.cpp>`_.
+<https://github.com/fmtlib/format-benchmark/blob/master/src/tinyformat-test.cc>`_.
 
 {fmt} is up to 20-30x faster than ``std::ostringstream`` and ``sprintf`` on
 floating-point formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
@@ -469,7 +469,7 @@ Boost Format
 
 This is a very powerful library which supports both ``printf``-like format
 strings and positional arguments. Its main drawback is performance. According to
-various, benchmarks it is much slower than other methods considered here. Boost
+various benchmarks, it is much slower than other methods considered here. Boost
 Format also has excessive build times and severe code bloat issues (see
 `Benchmarks`_).
 

doc/api.rst

@@ -37,10 +37,12 @@ similar to that of Python's `str.format
 <https://docs.python.org/3/library/stdtypes.html#str.format>`_.
 They take *fmt* and *args* as arguments.
 
-*fmt* is a format string that contains literal text and replacement
+*fmt* is a format string that contains literal text and replacement fields
-fields surrounded by braces ``{}``. The fields are replaced with formatted
+surrounded by braces ``{}``. The fields are replaced with formatted arguments
-arguments in the resulting string. A function taking *fmt* doesn't
+in the resulting string. `~fmt::format_string` is a format string which can be
-participate in an overload resolution if the latter is not a string.
+implicitly constructed from a string literal or a ``constexpr`` string and is
+checked at compile time in C++20. To pass a runtime format string wrap it in
+`fmt::runtime`.
 
 *args* is an argument list representing objects to be formatted.
 
@@ -50,7 +52,7 @@ participate in an overload resolution if the latter is not a string.
 .. doxygenfunction:: vformat(string_view fmt, format_args args) -> std::string
 
 .. doxygenfunction:: format_to(OutputIt out, format_string<T...> fmt, T&&... args) -> OutputIt
-.. doxygenfunction:: format_to_n(OutputIt out, size_t n, format_string<T...> fmt, const T&... args) -> format_to_n_result<OutputIt>
+.. doxygenfunction:: format_to_n(OutputIt out, size_t n, format_string<T...> fmt, T&&... args) -> format_to_n_result<OutputIt>
 .. doxygenfunction:: formatted_size(format_string<T...> fmt, T&&... args) -> size_t
 
 .. doxygenstruct:: fmt::format_to_n_result
@@ -59,7 +61,7 @@ participate in an overload resolution if the latter is not a string.
 .. _print:
 
 .. doxygenfunction:: fmt::print(format_string<T...> fmt, T&&... args)
-.. doxygenfunction:: vprint(string_view fmt, format_args args)
+.. doxygenfunction:: fmt::vprint(string_view fmt, format_args args)
 
 .. doxygenfunction:: print(std::FILE *f, format_string<T...> fmt, T&&... args)
 .. doxygenfunction:: vprint(std::FILE *f, string_view fmt, format_args args)
@@ -70,6 +72,7 @@ Compile-time Format String Checks
 Compile-time checks are enabled when using ``FMT_STRING``. They support built-in
 and string types as well as user-defined types with ``constexpr`` ``parse``
 functions in their ``formatter`` specializations.
+Requires C++14 and is a no-op in C++11.
 
 .. doxygendefine:: FMT_STRING
 
@@ -78,6 +81,13 @@ To force the use of compile-time checks, define the preprocessor variable
 will fail to compile with regular strings. Runtime-checked
 formatting is still possible using ``fmt::vformat``, ``fmt::vprint``, etc.
 
+.. doxygenclass:: fmt::basic_format_string
+   :members:
+
+.. doxygentypedef:: fmt::format_string
+
+.. doxygenfunction:: fmt::runtime(const S&)
+
 Named Arguments
 ---------------
 
@@ -177,7 +187,9 @@ template and implement ``parse`` and ``format`` methods::
 
   #include <fmt/format.h>
 
-  struct point { double x, y; };
+  struct point {
+    double x, y;
+  };
 
   template <> struct fmt::formatter<point> {
     // Presentation format: 'f' - fixed, 'e' - exponential.
@@ -201,8 +213,7 @@ template and implement ``parse`` and ``format`` methods::
       if (it != end && (*it == 'f' || *it == 'e')) presentation = *it++;
 
       // Check if reached the end of the range:
-      if (it != end && *it != '}')
+      if (it != end && *it != '}') throw format_error("invalid format");
-        throw format_error("invalid format");
 
       // Return an iterator past the end of the parsed range:
       return it;
@@ -213,10 +224,9 @@ template and implement ``parse`` and ``format`` methods::
     template <typename FormatContext>
     auto format(const point& p, FormatContext& ctx) -> decltype(ctx.out()) {
       // ctx.out() is an output iterator to write to.
-      return format_to(
+      return presentation == 'f'
-          ctx.out(),
+                ? format_to(ctx.out(), "({:.1f}, {:.1f})", p.x, p.y)
-          presentation == 'f' ? "({:.1f}, {:.1f})" : "({:.1e}, {:.1e})",
+                : format_to(ctx.out(), "({:.1e}, {:.1e})", p.x, p.y);
-          p.x, p.y);
     }
   };
 
@@ -314,6 +324,8 @@ Utilities
 
 .. doxygenfunction:: fmt::join(It begin, Sentinel end, string_view sep) -> join_view<It, Sentinel>
 
+.. doxygenfunction:: fmt::group_digits(T value) -> group_digits_view<T>
+
 .. doxygenclass:: fmt::detail::buffer
    :members:
 
@@ -350,8 +362,8 @@ allocator::
 
     custom_string vformat(custom_allocator alloc, fmt::string_view format_str,
                           fmt::format_args args) {
-      custom_memory_buffer buf(alloc);
+      auto buf = custom_memory_buffer(alloc);
-      fmt::vformat_to(buf, format_str, args);
+      fmt::vformat_to(std::back_inserter(buf), format_str, args);
       return custom_string(buf.data(), buf.size(), alloc);
     }
 
@@ -519,8 +531,8 @@ argument type doesn't match its format specification.
 ``wchar_t`` Support
 ===================
 
-The optional header ``fmt/wchar_t.h`` provides support for ``wchar_t`` and
+The optional header ``fmt/xchar.h`` provides support for ``wchar_t`` and exotic
-exotic character types.
+character types.
 
 .. doxygenstruct:: fmt::is_char
 

doc/basic-bootstrap/layout.html

@@ -90,12 +90,14 @@
         VERSION:     '{{ release|e }}',
         COLLAPSE_INDEX: false,
         FILE_SUFFIX: '{{ '' if no_search_suffix else file_suffix }}',
+        LINK_SUFFIX: '{{ link_suffix }}',
+        SOURCELINK_SUFFIX: '{{ sourcelink_suffix }}',
         HAS_SOURCE:  {{ has_source|lower }},
         SOURCELINK_SUFFIX:  '{{ sourcelink_suffix }}'
       };
     </script>
     {%- for scriptfile in script_files %}
-    <script type="text/javascript" src="{{ pathto(scriptfile, 1) }}"></script>
+    {{ js_tag(scriptfile) }}
     {%- endfor %}
 {%- endmacro %}
 

doc/build.py

@@ -4,7 +4,7 @@
 import errno, os, re, sys
 from subprocess import check_call, CalledProcessError, Popen, PIPE, STDOUT
 
-versions = ['1.0.0', '1.1.0', '2.0.0', '3.0.2', '4.0.0', '4.1.0', '5.0.0', '5.1.0', '5.2.0', '5.2.1', '5.3.0', '6.0.0', '6.1.0', '6.1.1', '6.1.2', '6.2.0', '6.2.1', '7.0.0', '7.0.1', '7.0.2', '7.0.3', '7.1.0', '7.1.1', '7.1.2', '7.1.3', '8.0.0']
+versions = ['1.0.0', '1.1.0', '2.0.0', '3.0.2', '4.0.0', '4.1.0', '5.0.0', '5.1.0', '5.2.0', '5.2.1', '5.3.0', '6.0.0', '6.1.0', '6.1.1', '6.1.2', '6.2.0', '6.2.1', '7.0.0', '7.0.1', '7.0.2', '7.0.3', '7.1.0', '7.1.1', '7.1.2', '7.1.3', '8.0.0', '8.0.1', '8.1.0', '8.1.1']
 
 class Pip:
   def __init__(self, venv_dir):
@@ -26,8 +26,10 @@ def create_build_env(venv_dir='virtualenv'):
   pip = Pip(venv_dir)
   pip.install('wheel')
   pip.install('six')
+  # See: https://github.com/sphinx-doc/sphinx/issues/9777
+  pip.install('docutils==0.17.1')
   pip.install('sphinx-doc/sphinx', 'v3.3.0')
-  pip.install('michaeljones/breathe', 'v4.16.0')
+  pip.install('michaeljones/breathe', 'v4.25.0')
 
 def build_docs(version='dev', **kwargs):
   doc_dir = kwargs.get('doc_dir', os.path.dirname(os.path.realpath(__file__)))
@@ -58,6 +60,7 @@ def build_docs(version='dev', **kwargs):
       MACRO_EXPANSION   = YES
       PREDEFINED        = _WIN32=1 \
                           __linux__=1 \
+                          FMT_ENABLE_IF(...)= \
                           FMT_USE_VARIADIC_TEMPLATES=1 \
                           FMT_USE_RVALUE_REFERENCES=1 \
                           FMT_USE_USER_DEFINED_LITERALS=1 \
@@ -66,6 +69,8 @@ def build_docs(version='dev', **kwargs):
                           "FMT_BEGIN_NAMESPACE=namespace fmt {{" \
                           "FMT_END_NAMESPACE=}}" \
                           "FMT_STRING_ALIAS=1" \
+                          "FMT_VARIADIC(...)=" \
+                          "FMT_VARIADIC_W(...)=" \
                           "FMT_DOC=1"
       EXCLUDE_SYMBOLS   = fmt::formatter fmt::printf_formatter fmt::arg_join \
                           fmt::basic_format_arg::handle

doc/syntax.rst

@@ -112,18 +112,18 @@ meaning in this case.
 The *sign* option is only valid for number types, and can be one of the
 following:
 
-+---------+----------------------------------------------------------+
++---------+------------------------------------------------------------+
-| Option  | Meaning                                                  |
+| Option  | Meaning                                                    |
-+=========+==========================================================+
++=========+============================================================+
-| ``'+'`` | indicates that a sign should be used for both            |
+| ``'+'`` | indicates that a sign should be used for both              |
-|         | positive as well as negative numbers.                    |
+|         | nonnegative as well as negative numbers.                   |
-+---------+----------------------------------------------------------+
++---------+------------------------------------------------------------+
-| ``'-'`` | indicates that a sign should be used only for negative   |
+| ``'-'`` | indicates that a sign should be used only for negative     |
-|         | numbers (this is the default behavior).                  |
+|         | numbers (this is the default behavior).                    |
-+---------+----------------------------------------------------------+
++---------+------------------------------------------------------------+
-| space   | indicates that a leading space should be used on         |
+| space   | indicates that a leading space should be used on           |
-|         | positive numbers, and a minus sign on negative numbers.  |
+|         | nonnegative numbers, and a minus sign on negative numbers. |
-+---------+----------------------------------------------------------+
++---------+------------------------------------------------------------+
 
 The ``'#'`` option causes the "alternate form" to be used for the
 conversion.  The alternate form is defined differently for different
@@ -161,7 +161,8 @@ displayed after the decimal point for a floating-point value formatted with
 value formatted with ``'g'`` or ``'G'``.  For non-number types the field
 indicates the maximum field size - in other words, how many characters will be
 used from the field content. The *precision* is not allowed for integer,
-character, Boolean, and pointer values.
+character, Boolean, and pointer values. Note that a C string must be
+null-terminated even if precision is specified.
 
 The ``'L'`` option uses the current locale setting to insert the appropriate
 number separator characters. This option is only valid for numeric types.
@@ -449,7 +450,7 @@ Using type-specific formatting::
 
 Using the comma as a thousands separator::
 
-   #include <fmt/locale.h>
+   #include <fmt/format.h>
 
    auto s = fmt::format(std::locale("en_US.UTF-8"), "{:L}", 1234567890);
    // s == "1,234,567,890"

include/fmt/args.h

@@ -143,6 +143,8 @@ class dynamic_format_arg_store
   }
 
  public:
+  constexpr dynamic_format_arg_store() = default;
+
   /**
     \rst
     Adds an argument into the dynamic store for later passing to a formatting

include/fmt/color.h

@@ -185,9 +185,13 @@ enum class terminal_color : uint8_t {
 
 enum class emphasis : uint8_t {
   bold = 1,
-  italic = 1 << 1,
+  faint = 1 << 1,
-  underline = 1 << 2,
+  italic = 1 << 2,
-  strikethrough = 1 << 3
+  underline = 1 << 3,
+  blink = 1 << 4,
+  reverse = 1 << 5,
+  conceal = 1 << 6,
+  strikethrough = 1 << 7,
 };
 
 // rgb is a struct for red, green and blue colors.
@@ -409,16 +413,18 @@ template <typename Char> struct ansi_color_escape {
     buffer[19] = static_cast<Char>(0);
   }
   FMT_CONSTEXPR ansi_color_escape(emphasis em) FMT_NOEXCEPT {
-    uint8_t em_codes[4] = {};
+    uint8_t em_codes[num_emphases] = {};
-    uint8_t em_bits = static_cast<uint8_t>(em);
+    if (has_emphasis(em, emphasis::bold)) em_codes[0] = 1;
-    if (em_bits & static_cast<uint8_t>(emphasis::bold)) em_codes[0] = 1;
+    if (has_emphasis(em, emphasis::faint)) em_codes[1] = 2;
-    if (em_bits & static_cast<uint8_t>(emphasis::italic)) em_codes[1] = 3;
+    if (has_emphasis(em, emphasis::italic)) em_codes[2] = 3;
-    if (em_bits & static_cast<uint8_t>(emphasis::underline)) em_codes[2] = 4;
+    if (has_emphasis(em, emphasis::underline)) em_codes[3] = 4;
-    if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
+    if (has_emphasis(em, emphasis::blink)) em_codes[4] = 5;
-      em_codes[3] = 9;
+    if (has_emphasis(em, emphasis::reverse)) em_codes[5] = 7;
+    if (has_emphasis(em, emphasis::conceal)) em_codes[6] = 8;
+    if (has_emphasis(em, emphasis::strikethrough)) em_codes[7] = 9;
 
     size_t index = 0;
-    for (int i = 0; i < 4; ++i) {
+    for (size_t i = 0; i < num_emphases; ++i) {
       if (!em_codes[i]) continue;
       buffer[index++] = static_cast<Char>('\x1b');
       buffer[index++] = static_cast<Char>('[');
@@ -435,7 +441,8 @@ template <typename Char> struct ansi_color_escape {
   }
 
  private:
-  Char buffer[7u + 3u * 4u + 1u];
+  static constexpr size_t num_emphases = 8;
+  Char buffer[7u + 3u * num_emphases + 1u];
 
   static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
                                    char delimiter) FMT_NOEXCEPT {
@@ -444,6 +451,10 @@ template <typename Char> struct ansi_color_escape {
     out[2] = static_cast<Char>('0' + c % 10);
     out[3] = static_cast<Char>(delimiter);
   }
+  static FMT_CONSTEXPR bool has_emphasis(emphasis em,
+                                         emphasis mask) FMT_NOEXCEPT {
+    return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
+  }
 };
 
 template <typename Char>
@@ -507,7 +518,7 @@ void vformat_to(buffer<Char>& buf, const text_style& ts,
     auto background = detail::make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  detail::vformat_to(buf, format_str, args);
+  detail::vformat_to(buf, format_str, args, {});
   if (has_style) detail::reset_color<Char>(buf);
 }
 

include/fmt/compile.h

@@ -156,7 +156,7 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
   \endrst
  */
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 #  define FMT_COMPILE(s) \
     FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
 #else
@@ -179,7 +179,7 @@ const T& first(const T& value, const Tail&...) {
   return value;
 }
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
@@ -190,7 +190,7 @@ constexpr const auto& get([[maybe_unused]] const T& first,
   if constexpr (N == 0)
     return first;
   else
-    return get<N - 1>(rest...);
+    return detail::get<N - 1>(rest...);
 }
 
 template <typename Char, typename... Args>
@@ -202,7 +202,8 @@ constexpr int get_arg_index_by_name(basic_string_view<Char> name,
 template <int N, typename> struct get_type_impl;
 
 template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
-  using type = remove_cvref_t<decltype(get<N>(std::declval<Args>()...))>;
+  using type =
+      remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
 };
 
 template <int N, typename T>
@@ -242,7 +243,7 @@ template <typename Char> struct code_unit {
 // This ensures that the argument type is convertible to `const T&`.
 template <typename T, int N, typename... Args>
 constexpr const T& get_arg_checked(const Args&... args) {
-  const auto& arg = get<N>(args...);
+  const auto& arg = detail::get<N>(args...);
   if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
     return arg.value;
   } else {
@@ -289,7 +290,7 @@ template <typename Char> struct runtime_named_field {
   constexpr OutputIt format(OutputIt out, const Args&... args) const {
     bool found = (try_format_argument(out, name, args) || ...);
     if (!found) {
-      throw format_error("argument with specified name is not found");
+      FMT_THROW(format_error("argument with specified name is not found"));
     }
     return out;
   }
@@ -399,7 +400,9 @@ template <typename Char> struct arg_id_handler {
     return 0;
   }
 
-  constexpr void on_error(const char* message) { throw format_error(message); }
+  constexpr void on_error(const char* message) {
+    FMT_THROW(format_error(message));
+  }
 };
 
 template <typename Char> struct parse_arg_id_result {
@@ -451,7 +454,7 @@ constexpr auto compile_format_string(S format_str) {
   constexpr auto str = basic_string_view<char_type>(format_str);
   if constexpr (str[POS] == '{') {
     if constexpr (POS + 1 == str.size())
-      throw format_error("unmatched '{' in format string");
+      FMT_THROW(format_error("unmatched '{' in format string"));
     if constexpr (str[POS + 1] == '{') {
       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
     } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
@@ -500,7 +503,7 @@ constexpr auto compile_format_string(S format_str) {
     }
   } else if constexpr (str[POS] == '}') {
     if constexpr (POS + 1 == str.size())
-      throw format_error("unmatched '}' in format string");
+      FMT_THROW(format_error("unmatched '}' in format string"));
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
@@ -527,12 +530,12 @@ constexpr auto compile(S format_str) {
     return result;
   }
 }
-#endif  // __cpp_if_constexpr
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
 FMT_MODULE_EXPORT_BEGIN
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,

include/fmt/format-inl.h

@@ -40,6 +40,10 @@ FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
   std::terminate();
 }
 
+FMT_FUNC void throw_format_error(const char* message) {
+  FMT_THROW(format_error(message));
+}
+
 #ifndef _MSC_VER
 #  define FMT_SNPRINTF snprintf
 #else  // _MSC_VER
@@ -145,141 +149,13 @@ template <> FMT_FUNC int count_digits<4>(detail::fallback_uintptr n) {
   return i >= 0 ? i * char_digits + count_digits<4, unsigned>(n.value[i]) : 1;
 }
 
-#if __cplusplus < 201703L
+// log10(2) = 0x0.4d104d427de7fbcc...
-template <typename T> constexpr const char basic_data<T>::digits[][2];
+static constexpr uint64_t log10_2_significand = 0x4d104d427de7fbcc;
-template <typename T> constexpr const char basic_data<T>::hex_digits[];
-template <typename T> constexpr const char basic_data<T>::signs[];
-template <typename T> constexpr const unsigned basic_data<T>::prefixes[];
-template <typename T> constexpr const char basic_data<T>::left_padding_shifts[];
-template <typename T>
-constexpr const char basic_data<T>::right_padding_shifts[];
-#endif
 
-template <typename T> struct bits {
+template <typename T = void> struct basic_impl_data {
-  static FMT_CONSTEXPR_DECL const int value =
-      static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
-};
-
-class fp;
-template <int SHIFT = 0> fp normalize(fp value);
-
-// Lower (upper) boundary is a value half way between a floating-point value
-// and its predecessor (successor). Boundaries have the same exponent as the
-// value so only significands are stored.
-struct boundaries {
-  uint64_t lower;
-  uint64_t upper;
-};
-
-// A handmade floating-point number f * pow(2, e).
-class fp {
- private:
-  using significand_type = uint64_t;
-
-  template <typename Float>
-  using is_supported_float = bool_constant<sizeof(Float) == sizeof(uint64_t) ||
-                                           sizeof(Float) == sizeof(uint32_t)>;
-
- public:
-  significand_type f;
-  int e;
-
-  // All sizes are in bits.
-  // Subtract 1 to account for an implicit most significant bit in the
-  // normalized form.
-  static FMT_CONSTEXPR_DECL const int double_significand_size =
-      std::numeric_limits<double>::digits - 1;
-  static FMT_CONSTEXPR_DECL const uint64_t implicit_bit =
-      1ULL << double_significand_size;
-  static FMT_CONSTEXPR_DECL const int significand_size =
-      bits<significand_type>::value;
-
-  fp() : f(0), e(0) {}
-  fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
-
-  // Constructs fp from an IEEE754 double. It is a template to prevent compile
-  // errors on platforms where double is not IEEE754.
-  template <typename Double> explicit fp(Double d) { assign(d); }
-
-  // Assigns d to this and return true iff predecessor is closer than successor.
-  template <typename Float, FMT_ENABLE_IF(is_supported_float<Float>::value)>
-  bool assign(Float d) {
-    // Assume float is in the format [sign][exponent][significand].
-    using limits = std::numeric_limits<Float>;
-    const int float_significand_size = limits::digits - 1;
-    const int exponent_size =
-        bits<Float>::value - float_significand_size - 1;  // -1 for sign
-    const uint64_t float_implicit_bit = 1ULL << float_significand_size;
-    const uint64_t significand_mask = float_implicit_bit - 1;
-    const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
-    const int exponent_bias = (1 << exponent_size) - limits::max_exponent - 1;
-    constexpr bool is_double = sizeof(Float) == sizeof(uint64_t);
-    auto u = bit_cast<conditional_t<is_double, uint64_t, uint32_t>>(d);
-    f = u & significand_mask;
-    int biased_e =
-        static_cast<int>((u & exponent_mask) >> float_significand_size);
-    // Predecessor is closer if d is a normalized power of 2 (f == 0) other than
-    // the smallest normalized number (biased_e > 1).
-    bool is_predecessor_closer = f == 0 && biased_e > 1;
-    if (biased_e != 0)
-      f += float_implicit_bit;
-    else
-      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
-    e = biased_e - exponent_bias - float_significand_size;
-    return is_predecessor_closer;
-  }
-
-  template <typename Float, FMT_ENABLE_IF(!is_supported_float<Float>::value)>
-  bool assign(Float) {
-    *this = fp();
-    return false;
-  }
-};
-
-// Normalizes the value converted from double and multiplied by (1 << SHIFT).
-template <int SHIFT> fp normalize(fp value) {
-  // Handle subnormals.
-  const auto shifted_implicit_bit = fp::implicit_bit << SHIFT;
-  while ((value.f & shifted_implicit_bit) == 0) {
-    value.f <<= 1;
-    --value.e;
-  }
-  // Subtract 1 to account for hidden bit.
-  const auto offset =
-      fp::significand_size - fp::double_significand_size - SHIFT - 1;
-  value.f <<= offset;
-  value.e -= offset;
-  return value;
-}
-
-inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
-
-// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
-inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
-#if FMT_USE_INT128
-  auto product = static_cast<__uint128_t>(lhs) * rhs;
-  auto f = static_cast<uint64_t>(product >> 64);
-  return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
-#else
-  // Multiply 32-bit parts of significands.
-  uint64_t mask = (1ULL << 32) - 1;
-  uint64_t a = lhs >> 32, b = lhs & mask;
-  uint64_t c = rhs >> 32, d = rhs & mask;
-  uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
-  // Compute mid 64-bit of result and round.
-  uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
-  return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
-#endif
-}
-
-inline fp operator*(fp x, fp y) { return {multiply(x.f, y.f), x.e + y.e + 64}; }
-
-// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
-// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
-inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
   // Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
   // These are generated by support/compute-powers.py.
-  static constexpr const uint64_t pow10_significands[] = {
+  static constexpr uint64_t pow10_significands[87] = {
       0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
       0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
       0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
@@ -311,9 +187,13 @@ inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
       0x9e19db92b4e31ba9, 0xeb96bf6ebadf77d9, 0xaf87023b9bf0ee6b,
   };
 
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wnarrowing"
+#endif
   // Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
   // to significands above.
-  static constexpr const int16_t pow10_exponents[] = {
+  static constexpr int16_t pow10_exponents[87] = {
       -1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
       -927,  -901,  -874,  -847,  -821,  -794,  -768,  -741,  -715,  -688, -661,
       -635,  -608,  -582,  -555,  -529,  -502,  -475,  -449,  -422,  -396, -369,
@@ -322,11 +202,137 @@ inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
       242,   269,   295,   322,   348,   375,   402,   428,   455,   481,  508,
       534,   561,   588,   614,   641,   667,   694,   720,   747,   774,  800,
       827,   853,   880,   907,   933,   960,   986,   1013,  1039,  1066};
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+#  pragma GCC diagnostic pop
+#endif
 
+  static constexpr uint64_t power_of_10_64[20] = {
+      1, FMT_POWERS_OF_10(1ULL), FMT_POWERS_OF_10(1000000000ULL),
+      10000000000000000000ULL};
+};
+
+// This is a struct rather than an alias to avoid shadowing warnings in gcc.
+struct impl_data : basic_impl_data<> {};
+
+#if __cplusplus < 201703L
+template <typename T>
+constexpr uint64_t basic_impl_data<T>::pow10_significands[];
+template <typename T> constexpr int16_t basic_impl_data<T>::pow10_exponents[];
+template <typename T> constexpr uint64_t basic_impl_data<T>::power_of_10_64[];
+#endif
+
+template <typename T> struct bits {
+  static FMT_CONSTEXPR_DECL const int value =
+      static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
+};
+
+// Returns the number of significand bits in Float excluding the implicit bit.
+template <typename Float> constexpr int num_significand_bits() {
+  // Subtract 1 to account for an implicit most significant bit in the
+  // normalized form.
+  return std::numeric_limits<Float>::digits - 1;
+}
+
+// A floating-point number f * pow(2, e).
+struct fp {
+  uint64_t f;
+  int e;
+
+  static constexpr const int num_significand_bits = bits<decltype(f)>::value;
+
+  constexpr fp() : f(0), e(0) {}
+  constexpr fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
+
+  // Constructs fp from an IEEE754 floating-point number. It is a template to
+  // prevent compile errors on systems where n is not IEEE754.
+  template <typename Float> explicit FMT_CONSTEXPR fp(Float n) { assign(n); }
+
+  template <typename Float>
+  using is_supported = bool_constant<sizeof(Float) == sizeof(uint64_t) ||
+                                     sizeof(Float) == sizeof(uint32_t)>;
+
+  // Assigns d to this and return true iff predecessor is closer than successor.
+  template <typename Float, FMT_ENABLE_IF(is_supported<Float>::value)>
+  FMT_CONSTEXPR bool assign(Float n) {
+    // Assume float is in the format [sign][exponent][significand].
+    const int num_float_significand_bits =
+        detail::num_significand_bits<Float>();
+    const uint64_t implicit_bit = 1ULL << num_float_significand_bits;
+    const uint64_t significand_mask = implicit_bit - 1;
+    constexpr bool is_double = sizeof(Float) == sizeof(uint64_t);
+    auto u = bit_cast<conditional_t<is_double, uint64_t, uint32_t>>(n);
+    f = u & significand_mask;
+    const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
+    int biased_e =
+        static_cast<int>((u & exponent_mask) >> num_float_significand_bits);
+    // The predecessor is closer if n is a normalized power of 2 (f == 0) other
+    // than the smallest normalized number (biased_e > 1).
+    bool is_predecessor_closer = f == 0 && biased_e > 1;
+    if (biased_e != 0)
+      f += implicit_bit;
+    else
+      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
+    const int exponent_bias = std::numeric_limits<Float>::max_exponent - 1;
+    e = biased_e - exponent_bias - num_float_significand_bits;
+    return is_predecessor_closer;
+  }
+
+  template <typename Float, FMT_ENABLE_IF(!is_supported<Float>::value)>
+  bool assign(Float) {
+    FMT_ASSERT(false, "");
+    return false;
+  }
+};
+
+// Normalizes the value converted from double and multiplied by (1 << SHIFT).
+template <int SHIFT = 0> FMT_CONSTEXPR fp normalize(fp value) {
+  // Handle subnormals.
+  const uint64_t implicit_bit = 1ULL << num_significand_bits<double>();
+  const auto shifted_implicit_bit = implicit_bit << SHIFT;
+  while ((value.f & shifted_implicit_bit) == 0) {
+    value.f <<= 1;
+    --value.e;
+  }
+  // Subtract 1 to account for hidden bit.
+  const auto offset =
+      fp::num_significand_bits - num_significand_bits<double>() - SHIFT - 1;
+  value.f <<= offset;
+  value.e -= offset;
+  return value;
+}
+
+inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
+
+// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
+FMT_CONSTEXPR inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
+#if FMT_USE_INT128
+  auto product = static_cast<__uint128_t>(lhs) * rhs;
+  auto f = static_cast<uint64_t>(product >> 64);
+  return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
+#else
+  // Multiply 32-bit parts of significands.
+  uint64_t mask = (1ULL << 32) - 1;
+  uint64_t a = lhs >> 32, b = lhs & mask;
+  uint64_t c = rhs >> 32, d = rhs & mask;
+  uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
+  // Compute mid 64-bit of result and round.
+  uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
+  return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
+#endif
+}
+
+FMT_CONSTEXPR inline fp operator*(fp x, fp y) {
+  return {multiply(x.f, y.f), x.e + y.e + 64};
+}
+
+// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
+// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
+FMT_CONSTEXPR inline fp get_cached_power(int min_exponent,
+                                         int& pow10_exponent) {
   const int shift = 32;
-  const auto significand = static_cast<int64_t>(data::log10_2_significand);
+  const auto significand = static_cast<int64_t>(log10_2_significand);
   int index = static_cast<int>(
-      ((min_exponent + fp::significand_size - 1) * (significand >> shift) +
+      ((min_exponent + fp::num_significand_bits - 1) * (significand >> shift) +
        ((int64_t(1) << shift) - 1))  // ceil
       >> 32                          // arithmetic shift
   );
@@ -336,7 +342,8 @@ inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
   const int dec_exp_step = 8;
   index = (index - first_dec_exp - 1) / dec_exp_step + 1;
   pow10_exponent = first_dec_exp + index * dec_exp_step;
-  return {pow10_significands[index], pow10_exponents[index]};
+  return {impl_data::pow10_significands[index],
+          impl_data::pow10_exponents[index]};
 }
 
 // A simple accumulator to hold the sums of terms in bigint::square if uint128_t
@@ -345,14 +352,16 @@ struct accumulator {
   uint64_t lower;
   uint64_t upper;
 
-  accumulator() : lower(0), upper(0) {}
+  constexpr accumulator() : lower(0), upper(0) {}
-  explicit operator uint32_t() const { return static_cast<uint32_t>(lower); }
+  constexpr explicit operator uint32_t() const {
+    return static_cast<uint32_t>(lower);
+  }
 
-  void operator+=(uint64_t n) {
+  FMT_CONSTEXPR void operator+=(uint64_t n) {
     lower += n;
     if (lower < n) ++upper;
   }
-  void operator>>=(int shift) {
+  FMT_CONSTEXPR void operator>>=(int shift) {
     FMT_ASSERT(shift == 32, "");
     (void)shift;
     lower = (upper << 32) | (lower >> 32);
@@ -370,27 +379,31 @@ class bigint {
   basic_memory_buffer<bigit, bigits_capacity> bigits_;
   int exp_;
 
-  bigit operator[](int index) const { return bigits_[to_unsigned(index)]; }
+  FMT_CONSTEXPR20 bigit operator[](int index) const {
-  bigit& operator[](int index) { return bigits_[to_unsigned(index)]; }
+    return bigits_[to_unsigned(index)];
+  }
+  FMT_CONSTEXPR20 bigit& operator[](int index) {
+    return bigits_[to_unsigned(index)];
+  }
 
   static FMT_CONSTEXPR_DECL const int bigit_bits = bits<bigit>::value;
 
   friend struct formatter<bigint>;
 
-  void subtract_bigits(int index, bigit other, bigit& borrow) {
+  FMT_CONSTEXPR20 void subtract_bigits(int index, bigit other, bigit& borrow) {
     auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
     (*this)[index] = static_cast<bigit>(result);
     borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
   }
 
-  void remove_leading_zeros() {
+  FMT_CONSTEXPR20 void remove_leading_zeros() {
     int num_bigits = static_cast<int>(bigits_.size()) - 1;
     while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
     bigits_.resize(to_unsigned(num_bigits + 1));
   }
 
   // Computes *this -= other assuming aligned bigints and *this >= other.
-  void subtract_aligned(const bigint& other) {
+  FMT_CONSTEXPR20 void subtract_aligned(const bigint& other) {
     FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
     FMT_ASSERT(compare(*this, other) >= 0, "");
     bigit borrow = 0;
@@ -401,7 +414,7 @@ class bigint {
     remove_leading_zeros();
   }
 
-  void multiply(uint32_t value) {
+  FMT_CONSTEXPR20 void multiply(uint32_t value) {
     const double_bigit wide_value = value;
     bigit carry = 0;
     for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
@@ -412,7 +425,7 @@ class bigint {
     if (carry != 0) bigits_.push_back(carry);
   }
 
-  void multiply(uint64_t value) {
+  FMT_CONSTEXPR20 void multiply(uint64_t value) {
     const bigit mask = ~bigit(0);
     const double_bigit lower = value & mask;
     const double_bigit upper = value >> bigit_bits;
@@ -430,14 +443,16 @@ class bigint {
   }
 
  public:
-  bigint() : exp_(0) {}
+  FMT_CONSTEXPR20 bigint() : exp_(0) {}
   explicit bigint(uint64_t n) { assign(n); }
-  ~bigint() { FMT_ASSERT(bigits_.capacity() <= bigits_capacity, ""); }
+  FMT_CONSTEXPR20 ~bigint() {
+    FMT_ASSERT(bigits_.capacity() <= bigits_capacity, "");
+  }
 
   bigint(const bigint&) = delete;
   void operator=(const bigint&) = delete;
 
-  void assign(const bigint& other) {
+  FMT_CONSTEXPR20 void assign(const bigint& other) {
     auto size = other.bigits_.size();
     bigits_.resize(size);
     auto data = other.bigits_.data();
@@ -445,7 +460,7 @@ class bigint {
     exp_ = other.exp_;
   }
 
-  void assign(uint64_t n) {
+  FMT_CONSTEXPR20 void assign(uint64_t n) {
     size_t num_bigits = 0;
     do {
       bigits_[num_bigits++] = n & ~bigit(0);
@@ -455,9 +470,11 @@ class bigint {
     exp_ = 0;
   }
 
-  int num_bigits() const { return static_cast<int>(bigits_.size()) + exp_; }
+  FMT_CONSTEXPR20 int num_bigits() const {
+    return static_cast<int>(bigits_.size()) + exp_;
+  }
 
-  FMT_NOINLINE bigint& operator<<=(int shift) {
+  FMT_NOINLINE FMT_CONSTEXPR20 bigint& operator<<=(int shift) {
     FMT_ASSERT(shift >= 0, "");
     exp_ += shift / bigit_bits;
     shift %= bigit_bits;
@@ -472,13 +489,13 @@ class bigint {
     return *this;
   }
 
-  template <typename Int> bigint& operator*=(Int value) {
+  template <typename Int> FMT_CONSTEXPR20 bigint& operator*=(Int value) {
     FMT_ASSERT(value > 0, "");
     multiply(uint32_or_64_or_128_t<Int>(value));
     return *this;
   }
 
-  friend int compare(const bigint& lhs, const bigint& rhs) {
+  friend FMT_CONSTEXPR20 int compare(const bigint& lhs, const bigint& rhs) {
     int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
     if (num_lhs_bigits != num_rhs_bigits)
       return num_lhs_bigits > num_rhs_bigits ? 1 : -1;
@@ -495,8 +512,8 @@ class bigint {
   }
 
   // Returns compare(lhs1 + lhs2, rhs).
-  friend int add_compare(const bigint& lhs1, const bigint& lhs2,
+  friend FMT_CONSTEXPR20 int add_compare(const bigint& lhs1, const bigint& lhs2,
-                         const bigint& rhs) {
+                                         const bigint& rhs) {
     int max_lhs_bigits = (std::max)(lhs1.num_bigits(), lhs2.num_bigits());
     int num_rhs_bigits = rhs.num_bigits();
     if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
@@ -519,7 +536,7 @@ class bigint {
   }
 
   // Assigns pow(10, exp) to this bigint.
-  void assign_pow10(int exp) {
+  FMT_CONSTEXPR20 void assign_pow10(int exp) {
     FMT_ASSERT(exp >= 0, "");
     if (exp == 0) return assign(1);
     // Find the top bit.
@@ -538,7 +555,7 @@ class bigint {
     *this <<= exp;  // Multiply by pow(2, exp) by shifting.
   }
 
-  void square() {
+  FMT_CONSTEXPR20 void square() {
     int num_bigits = static_cast<int>(bigits_.size());
     int num_result_bigits = 2 * num_bigits;
     basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
@@ -563,14 +580,13 @@ class bigint {
       (*this)[bigit_index] = static_cast<bigit>(sum);
       sum >>= bits<bigit>::value;
     }
-    --num_result_bigits;
     remove_leading_zeros();
     exp_ *= 2;
   }
 
   // If this bigint has a bigger exponent than other, adds trailing zero to make
   // exponents equal. This simplifies some operations such as subtraction.
-  void align(const bigint& other) {
+  FMT_CONSTEXPR20 void align(const bigint& other) {
     int exp_difference = exp_ - other.exp_;
     if (exp_difference <= 0) return;
     int num_bigits = static_cast<int>(bigits_.size());
@@ -583,7 +599,7 @@ class bigint {
 
   // Divides this bignum by divisor, assigning the remainder to this and
   // returning the quotient.
-  int divmod_assign(const bigint& divisor) {
+  FMT_CONSTEXPR20 int divmod_assign(const bigint& divisor) {
     FMT_ASSERT(this != &divisor, "");
     if (compare(*this, divisor) < 0) return 0;
     FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");
@@ -603,8 +619,9 @@ enum class round_direction { unknown, up, down };
 // some number v and the error, returns whether v should be rounded up, down, or
 // whether the rounding direction can't be determined due to error.
 // error should be less than divisor / 2.
-inline round_direction get_round_direction(uint64_t divisor, uint64_t remainder,
+FMT_CONSTEXPR inline round_direction get_round_direction(uint64_t divisor,
-                                           uint64_t error) {
+                                                         uint64_t remainder,
+                                                         uint64_t error) {
   FMT_ASSERT(remainder < divisor, "");  // divisor - remainder won't overflow.
   FMT_ASSERT(error < divisor, "");      // divisor - error won't overflow.
   FMT_ASSERT(error < divisor - error, "");  // error * 2 won't overflow.
@@ -627,19 +644,52 @@ enum result {
 };
 }
 
-inline uint64_t power_of_10_64(int exp) {
+struct gen_digits_handler {
-  static constexpr const uint64_t data[] = {1, FMT_POWERS_OF_10(1),
+  char* buf;
-                                            FMT_POWERS_OF_10(1000000000ULL),
+  int size;
-                                            10000000000000000000ULL};
+  int precision;
-  return data[exp];
+  int exp10;
-}
+  bool fixed;
+
+  FMT_CONSTEXPR digits::result on_digit(char digit, uint64_t divisor,
+                                        uint64_t remainder, uint64_t error,
+                                        bool integral) {
+    FMT_ASSERT(remainder < divisor, "");
+    buf[size++] = digit;
+    if (!integral && error >= remainder) return digits::error;
+    if (size < precision) return digits::more;
+    if (!integral) {
+      // Check if error * 2 < divisor with overflow prevention.
+      // The check is not needed for the integral part because error = 1
+      // and divisor > (1 << 32) there.
+      if (error >= divisor || error >= divisor - error) return digits::error;
+    } else {
+      FMT_ASSERT(error == 1 && divisor > 2, "");
+    }
+    auto dir = get_round_direction(divisor, remainder, error);
+    if (dir != round_direction::up)
+      return dir == round_direction::down ? digits::done : digits::error;
+    ++buf[size - 1];
+    for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
+      buf[i] = '0';
+      ++buf[i - 1];
+    }
+    if (buf[0] > '9') {
+      buf[0] = '1';
+      if (fixed)
+        buf[size++] = '0';
+      else
+        ++exp10;
+    }
+    return digits::done;
+  }
+};
 
 // Generates output using the Grisu digit-gen algorithm.
 // error: the size of the region (lower, upper) outside of which numbers
 // definitely do not round to value (Delta in Grisu3).
-template <typename Handler>
+FMT_INLINE FMT_CONSTEXPR20 digits::result grisu_gen_digits(
-FMT_INLINE digits::result grisu_gen_digits(fp value, uint64_t error, int& exp,
+    fp value, uint64_t error, int& exp, gen_digits_handler& handler) {
-                                           Handler& handler) {
   const fp one(1ULL << -value.e, value.e);
   // The integral part of scaled value (p1 in Grisu) = value / one. It cannot be
   // zero because it contains a product of two 64-bit numbers with MSB set (due
@@ -650,10 +700,28 @@ FMT_INLINE digits::result grisu_gen_digits(fp value, uint64_t error, int& exp,
   // The fractional part of scaled value (p2 in Grisu) c = value % one.
   uint64_t fractional = value.f & (one.f - 1);
   exp = count_digits(integral);  // kappa in Grisu.
-  // Divide by 10 to prevent overflow.
+  // Non-fixed formats require at least one digit and no precision adjustment.
-  auto result = handler.on_start(power_of_10_64(exp - 1) << -one.e,
+  if (handler.fixed) {
-                                 value.f / 10, error * 10, exp);
+    // Adjust fixed precision by exponent because it is relative to decimal
-  if (result != digits::more) return result;
+    // point.
+    int precision_offset = exp + handler.exp10;
+    if (precision_offset > 0 &&
+        handler.precision > max_value<int>() - precision_offset) {
+      FMT_THROW(format_error("number is too big"));
+    }
+    handler.precision += precision_offset;
+    // Check if precision is satisfied just by leading zeros, e.g.
+    // format("{:.2f}", 0.001) gives "0.00" without generating any digits.
+    if (handler.precision <= 0) {
+      if (handler.precision < 0) return digits::done;
+      // Divide by 10 to prevent overflow.
+      uint64_t divisor = impl_data::power_of_10_64[exp - 1] << -one.e;
+      auto dir = get_round_direction(divisor, value.f / 10, error * 10);
+      if (dir == round_direction::unknown) return digits::error;
+      handler.buf[handler.size++] = dir == round_direction::up ? '1' : '0';
+      return digits::done;
+    }
+  }
   // Generate digits for the integral part. This can produce up to 10 digits.
   do {
     uint32_t digit = 0;
@@ -700,9 +768,9 @@ FMT_INLINE digits::result grisu_gen_digits(fp value, uint64_t error, int& exp,
     }
     --exp;
     auto remainder = (static_cast<uint64_t>(integral) << -one.e) + fractional;
-    result = handler.on_digit(static_cast<char>('0' + digit),
+    auto result = handler.on_digit(static_cast<char>('0' + digit),
-                              power_of_10_64(exp) << -one.e, remainder, error,
+                                   impl_data::power_of_10_64[exp] << -one.e,
-                              exp, true);
+                                   remainder, error, true);
     if (result != digits::more) return result;
   } while (exp > 0);
   // Generate digits for the fractional part.
@@ -712,69 +780,11 @@ FMT_INLINE digits::result grisu_gen_digits(fp value, uint64_t error, int& exp,
     char digit = static_cast<char>('0' + (fractional >> -one.e));
     fractional &= one.f - 1;
     --exp;
-    result = handler.on_digit(digit, one.f, fractional, error, exp, false);
+    auto result = handler.on_digit(digit, one.f, fractional, error, false);
     if (result != digits::more) return result;
   }
 }
 
-// The fixed precision digit handler.
-struct fixed_handler {
-  char* buf;
-  int size;
-  int precision;
-  int exp10;
-  bool fixed;
-
-  digits::result on_start(uint64_t divisor, uint64_t remainder, uint64_t error,
-                          int& exp) {
-    // Non-fixed formats require at least one digit and no precision adjustment.
-    if (!fixed) return digits::more;
-    // Adjust fixed precision by exponent because it is relative to decimal
-    // point.
-    precision += exp + exp10;
-    // Check if precision is satisfied just by leading zeros, e.g.
-    // format("{:.2f}", 0.001) gives "0.00" without generating any digits.
-    if (precision > 0) return digits::more;
-    if (precision < 0) return digits::done;
-    auto dir = get_round_direction(divisor, remainder, error);
-    if (dir == round_direction::unknown) return digits::error;
-    buf[size++] = dir == round_direction::up ? '1' : '0';
-    return digits::done;
-  }
-
-  digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
-                          uint64_t error, int, bool integral) {
-    FMT_ASSERT(remainder < divisor, "");
-    buf[size++] = digit;
-    if (!integral && error >= remainder) return digits::error;
-    if (size < precision) return digits::more;
-    if (!integral) {
-      // Check if error * 2 < divisor with overflow prevention.
-      // The check is not needed for the integral part because error = 1
-      // and divisor > (1 << 32) there.
-      if (error >= divisor || error >= divisor - error) return digits::error;
-    } else {
-      FMT_ASSERT(error == 1 && divisor > 2, "");
-    }
-    auto dir = get_round_direction(divisor, remainder, error);
-    if (dir != round_direction::up)
-      return dir == round_direction::down ? digits::done : digits::error;
-    ++buf[size - 1];
-    for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
-      buf[i] = '0';
-      ++buf[i - 1];
-    }
-    if (buf[0] > '9') {
-      buf[0] = '1';
-      if (fixed)
-        buf[size++] = '0';
-      else
-        ++exp10;
-    }
-    return digits::done;
-  }
-};
-
 // A 128-bit integer type used internally,
 struct uint128_wrapper {
   uint128_wrapper() = default;
@@ -898,8 +908,7 @@ inline uint64_t umul96_lower64(uint32_t x, uint64_t y) FMT_NOEXCEPT {
 inline int floor_log10_pow2(int e) FMT_NOEXCEPT {
   FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
   const int shift = 22;
-  return (e * static_cast<int>(data::log10_2_significand >> (64 - shift))) >>
+  return (e * static_cast<int>(log10_2_significand >> (64 - shift))) >> shift;
-         shift;
 }
 
 // Various fast log computations.
@@ -917,8 +926,7 @@ inline int floor_log10_pow2_minus_log10_4_over_3(int e) FMT_NOEXCEPT {
   FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
   const uint64_t log10_4_over_3_fractional_digits = 0x1ffbfc2bbc780375;
   const int shift_amount = 22;
-  return (e * static_cast<int>(data::log10_2_significand >>
+  return (e * static_cast<int>(log10_2_significand >> (64 - shift_amount)) -
-                               (64 - shift_amount)) -
           static_cast<int>(log10_4_over_3_fractional_digits >>
                            (64 - shift_amount))) >>
          shift_amount;
@@ -1043,7 +1051,7 @@ template <> struct cache_accessor<float> {
   static uint64_t get_cached_power(int k) FMT_NOEXCEPT {
     FMT_ASSERT(k >= float_info<float>::min_k && k <= float_info<float>::max_k,
                "k is out of range");
-    constexpr const uint64_t pow10_significands[] = {
+    static constexpr const uint64_t pow10_significands[] = {
         0x81ceb32c4b43fcf5, 0xa2425ff75e14fc32, 0xcad2f7f5359a3b3f,
         0xfd87b5f28300ca0e, 0x9e74d1b791e07e49, 0xc612062576589ddb,
         0xf79687aed3eec552, 0x9abe14cd44753b53, 0xc16d9a0095928a28,
@@ -2211,24 +2219,21 @@ small_divisor_case_label:
 }
 }  // namespace dragonbox
 
-// Formats value using a variation of the Fixed-Precision Positive
+// Formats a floating-point number using a variation of the Fixed-Precision
-// Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
+// Positive Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
 // https://fmt.dev/papers/p372-steele.pdf.
-template <typename Double>
+FMT_CONSTEXPR20 inline void format_dragon(fp value, bool is_predecessor_closer,
-void fallback_format(Double d, int num_digits, bool binary32, buffer<char>& buf,
+                                          int num_digits, buffer<char>& buf,
-                     int& exp10) {
+                                          int& exp10) {
   bigint numerator;    // 2 * R in (FPP)^2.
   bigint denominator;  // 2 * S in (FPP)^2.
   // lower and upper are differences between value and corresponding boundaries.
   bigint lower;             // (M^- in (FPP)^2).
   bigint upper_store;       // upper's value if different from lower.
   bigint* upper = nullptr;  // (M^+ in (FPP)^2).
-  fp value;
   // Shift numerator and denominator by an extra bit or two (if lower boundary
   // is closer) to make lower and upper integers. This eliminates multiplication
   // by 2 during later computations.
-  const bool is_predecessor_closer =
-      binary32 ? value.assign(static_cast<float>(d)) : value.assign(d);
   int shift = is_predecessor_closer ? 2 : 1;
   uint64_t significand = value.f << shift;
   if (value.e >= 0) {
@@ -2298,9 +2303,9 @@ void fallback_format(Double d, int num_digits, bool binary32, buffer<char>& buf,
   // Generate the given number of digits.
   exp10 -= num_digits - 1;
   if (num_digits == 0) {
-    buf.try_resize(1);
     denominator *= 10;
-    buf[0] = add_compare(numerator, numerator, denominator) > 0 ? '1' : '0';
+    auto digit = add_compare(numerator, numerator, denominator) > 0 ? '1' : '0';
+    buf.push_back(digit);
     return;
   }
   buf.try_resize(to_unsigned(num_digits));
@@ -2331,9 +2336,12 @@ void fallback_format(Double d, int num_digits, bool binary32, buffer<char>& buf,
   buf[num_digits - 1] = static_cast<char>('0' + digit);
 }
 
-template <typename T>
+template <typename Float>
-int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
+FMT_HEADER_ONLY_CONSTEXPR20 int format_float(Float value, int precision,
-  static_assert(!std::is_same<T, float>::value, "");
+                                             float_specs specs,
+                                             buffer<char>& buf) {
+  // float is passed as double to reduce the number of instantiations.
+  static_assert(!std::is_same<Float, float>::value, "");
   FMT_ASSERT(value >= 0, "value is negative");
 
   const bool fixed = specs.format == float_format::fixed;
@@ -2343,13 +2351,13 @@ int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
       return 0;
     }
     buf.try_resize(to_unsigned(precision));
-    std::uninitialized_fill_n(buf.data(), precision, '0');
+    fill_n(buf.data(), precision, '0');
     return -precision;
   }
 
-  if (!specs.use_grisu) return snprintf_float(value, precision, specs, buf);
+  if (specs.fallback) return snprintf_float(value, precision, specs, buf);
 
-  if (precision < 0) {
+  if (!is_constant_evaluated() && precision < 0) {
     // Use Dragonbox for the shortest format.
     if (specs.binary32) {
       auto dec = dragonbox::to_decimal(static_cast<float>(value));
@@ -2361,26 +2369,37 @@ int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
     return dec.exponent;
   }
 
-  // Use Grisu + Dragon4 for the given precision:
-  // https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf.
   int exp = 0;
-  const int min_exp = -60;  // alpha in Grisu.
+  bool use_dragon = true;
-  int cached_exp10 = 0;     // K in Grisu.
+  if (is_fast_float<Float>()) {
-  fp normalized = normalize(fp(value));
+    // Use Grisu + Dragon4 for the given precision:
-  const auto cached_pow = get_cached_power(
+    // https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf.
-      min_exp - (normalized.e + fp::significand_size), cached_exp10);
+    const int min_exp = -60;  // alpha in Grisu.
-  normalized = normalized * cached_pow;
+    int cached_exp10 = 0;     // K in Grisu.
-  // Limit precision to the maximum possible number of significant digits in an
+    fp normalized = normalize(fp(value));
-  // IEEE754 double because we don't need to generate zeros.
+    const auto cached_pow = get_cached_power(
-  const int max_double_digits = 767;
+        min_exp - (normalized.e + fp::num_significand_bits), cached_exp10);
-  if (precision > max_double_digits) precision = max_double_digits;
+    normalized = normalized * cached_pow;
-  fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
+    gen_digits_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
-  if (grisu_gen_digits(normalized, 1, exp, handler) == digits::error) {
+    if (grisu_gen_digits(normalized, 1, exp, handler) != digits::error &&
-    exp += handler.size - cached_exp10 - 1;
+        !is_constant_evaluated()) {
-    fallback_format(value, handler.precision, specs.binary32, buf, exp);
+      exp += handler.exp10;
-  } else {
+      buf.try_resize(to_unsigned(handler.size));
-    exp += handler.exp10;
+      use_dragon = false;
-    buf.try_resize(to_unsigned(handler.size));
+    } else {
+      exp += handler.size - cached_exp10 - 1;
+      precision = handler.precision;
+    }
+  }
+  if (use_dragon) {
+    auto f = fp();
+    bool is_predecessor_closer =
+        specs.binary32 ? f.assign(static_cast<float>(value)) : f.assign(value);
+    // Limit precision to the maximum possible number of significant digits in
+    // an IEEE754 double because we don't need to generate zeros.
+    const int max_double_digits = 767;
+    if (precision > max_double_digits) precision = max_double_digits;
+    format_dragon(f, is_predecessor_closer, precision, buf, exp);
   }
   if (!fixed && !specs.showpoint) {
     // Remove trailing zeros.
@@ -2392,7 +2411,7 @@ int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
     buf.try_resize(num_digits);
   }
   return exp;
-}  // namespace detail
+}
 
 template <typename T>
 int snprintf_float(T value, int precision, float_specs specs,
@@ -2526,8 +2545,8 @@ template <> struct formatter<detail::bigint> {
 };
 
 FMT_FUNC detail::utf8_to_utf16::utf8_to_utf16(string_view s) {
-  for_each_codepoint(s, [this](uint32_t cp, int error) {
+  for_each_codepoint(s, [this](uint32_t cp, string_view) {
-    if (error != 0) FMT_THROW(std::runtime_error("invalid utf8"));
+    if (cp == invalid_code_point) FMT_THROW(std::runtime_error("invalid utf8"));
     if (cp <= 0xFFFF) {
       buffer_.push_back(static_cast<wchar_t>(cp));
     } else {
@@ -2535,6 +2554,7 @@ FMT_FUNC detail::utf8_to_utf16::utf8_to_utf16(string_view s) {
       buffer_.push_back(static_cast<wchar_t>(0xD800 + (cp >> 10)));
       buffer_.push_back(static_cast<wchar_t>(0xDC00 + (cp & 0x3FF)));
     }
+    return true;
   });
   buffer_.push_back(0);
 }
@@ -2550,15 +2570,17 @@ FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
   format_error_code(out, error_code, message);
 }
 
-FMT_FUNC void detail::error_handler::on_error(const char* message) {
-  FMT_THROW(format_error(message));
-}
-
 FMT_FUNC void report_system_error(int error_code,
                                   const char* message) FMT_NOEXCEPT {
   report_error(format_system_error, error_code, message);
 }
 
+// DEPRECATED!
+// This function is defined here and not inline for ABI compatiblity.
+FMT_FUNC void detail::error_handler::on_error(const char* message) {
+  throw_format_error(message);
+}
+
 FMT_FUNC std::string vformat(string_view fmt, format_args args) {
   // Don't optimize the "{}" case to keep the binary size small and because it
   // can be better optimized in fmt::format anyway.

include/fmt/os.h

@@ -21,17 +21,20 @@
 
 #include "format.h"
 
+#ifndef FMT_USE_FCNTL
 // UWP doesn't provide _pipe.
-#if FMT_HAS_INCLUDE("winapifamily.h")
+#  if FMT_HAS_INCLUDE("winapifamily.h")
-#  include <winapifamily.h>
+#    include <winapifamily.h>
-#endif
+#  endif
-#if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+#  if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
-     defined(__linux__)) &&                              \
+       defined(__linux__)) &&                              \
-    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+      (!defined(WINAPI_FAMILY) ||                          \
-#  include <fcntl.h>  // for O_RDONLY
+       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
-#  define FMT_USE_FCNTL 1
+#    include <fcntl.h>  // for O_RDONLY
-#else
+#    define FMT_USE_FCNTL 1
-#  define FMT_USE_FCNTL 0
+#  else
+#    define FMT_USE_FCNTL 0
+#  endif
 #endif
 
 #ifndef FMT_POSIX
@@ -390,23 +393,26 @@ struct ostream_params {
       : ostream_params(params...) {
     this->buffer_size = bs.value;
   }
+
+// Intel has a bug that results in failure to deduce a constructor
+// for empty parameter packs.
+#  if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 2000
+  ostream_params(int new_oflag) : oflag(new_oflag) {}
+  ostream_params(detail::buffer_size bs) : buffer_size(bs.value) {}
+#  endif
 };
 
 FMT_END_DETAIL_NAMESPACE
 
-static constexpr detail::buffer_size buffer_size;
+// Added {} below to work around default constructor error known to
+// occur in Xcode versions 7.2.1 and 8.2.1.
+constexpr detail::buffer_size buffer_size{};
 
 /** A fast output stream which is not thread-safe. */
 class FMT_API ostream final : private detail::buffer<char> {
  private:
   file file_;
 
-  void flush() {
-    if (size() == 0) return;
-    file_.write(data(), size());
-    clear();
-  }
-
   void grow(size_t) override;
 
   ostream(cstring_view path, const detail::ostream_params& params)
@@ -426,6 +432,12 @@ class FMT_API ostream final : private detail::buffer<char> {
     delete[] data();
   }
 
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size());
+    clear();
+  }
+
   template <typename... T>
   friend ostream output_file(cstring_view path, T... params);
 
@@ -500,7 +512,7 @@ class locale {
 
   // Converts string to floating-point number and advances str past the end
   // of the parsed input.
-  double strtod(const char*& str) const {
+  FMT_DEPRECATED double strtod(const char*& str) const {
     char* end = nullptr;
     double result = strtod_l(str, &end, locale_);
     str = end;

include/fmt/ostream.h

@@ -14,73 +14,20 @@
 
 FMT_BEGIN_NAMESPACE
 
-template <typename Char> class basic_printf_parse_context;
 template <typename OutputIt, typename Char> class basic_printf_context;
 
 namespace detail {
 
-template <class Char> class formatbuf : public std::basic_streambuf<Char> {
+// Checks if T has a user-defined operator<<.
- private:
+template <typename T, typename Char, typename Enable = void>
-  using int_type = typename std::basic_streambuf<Char>::int_type;
+class is_streamable {
-  using traits_type = typename std::basic_streambuf<Char>::traits_type;
-
-  buffer<Char>& buffer_;
-
- public:
-  formatbuf(buffer<Char>& buf) : buffer_(buf) {}
-
- protected:
-  // The put-area is actually always empty. This makes the implementation
-  // simpler and has the advantage that the streambuf and the buffer are always
-  // in sync and sputc never writes into uninitialized memory. The obvious
-  // disadvantage is that each call to sputc always results in a (virtual) call
-  // to overflow. There is no disadvantage here for sputn since this always
-  // results in a call to xsputn.
-
-  int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
-    if (!traits_type::eq_int_type(ch, traits_type::eof()))
-      buffer_.push_back(static_cast<Char>(ch));
-    return ch;
-  }
-
-  std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
-    buffer_.append(s, s + count);
-    return count;
-  }
-};
-
-struct converter {
-  template <typename T, FMT_ENABLE_IF(is_integral<T>::value)> converter(T);
-};
-
-template <typename Char> struct test_stream : std::basic_ostream<Char> {
- private:
-  void_t<> operator<<(converter);
-};
-
-// Hide insertion operators for built-in types.
-template <typename Char, typename Traits>
-void_t<> operator<<(std::basic_ostream<Char, Traits>&, Char);
-template <typename Char, typename Traits>
-void_t<> operator<<(std::basic_ostream<Char, Traits>&, char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, signed char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, unsigned char);
-
-// Checks if T has a user-defined operator<< (e.g. not a member of
-// std::ostream).
-template <typename T, typename Char> class is_streamable {
  private:
   template <typename U>
-  static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
+  static auto test(int)
-                                              << std::declval<U>()),
+      -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>()
-                                     void_t<>>::value>
+                              << std::declval<U>()) != 0>;
-  test(int);
 
-  template <typename> static std::false_type test(...);
+  template <typename> static auto test(...) -> std::false_type;
 
   using result = decltype(test<T>(0));
 
@@ -90,7 +37,21 @@ template <typename T, typename Char> class is_streamable {
   static const bool value = result::value;
 };
 
+// Formatting of built-in types and arrays is intentionally disabled because
+// it's handled by standard (non-ostream) formatters.
+template <typename T, typename Char>
+struct is_streamable<
+    T, Char,
+    enable_if_t<
+        std::is_arithmetic<T>::value || std::is_array<T>::value ||
+        std::is_pointer<T>::value || std::is_same<T, char8_type>::value ||
+        std::is_same<T, std::basic_string<Char>>::value ||
+        std::is_same<T, std_string_view<Char>>::value ||
+        (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>>
+    : std::false_type {};
+
 // Write the content of buf to os.
+// It is a separate function rather than a part of vprint to simplify testing.
 template <typename Char>
 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
@@ -108,8 +69,8 @@ void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
 template <typename Char, typename T>
 void format_value(buffer<Char>& buf, const T& value,
                   locale_ref loc = locale_ref()) {
-  formatbuf<Char> format_buf(buf);
+  auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
-  std::basic_ostream<Char> output(&format_buf);
+  auto&& output = std::basic_ostream<Char>(&format_buf);
 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
   if (loc) output.imbue(loc.get<std::locale>());
 #endif
@@ -122,29 +83,22 @@ void format_value(buffer<Char>& buf, const T& value,
 template <typename T, typename Char>
 struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
     : private formatter<basic_string_view<Char>, Char> {
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+  using formatter<basic_string_view<Char>, Char>::parse;
-      -> decltype(ctx.begin()) {
-    return formatter<basic_string_view<Char>, Char>::parse(ctx);
-  }
-  template <typename ParseCtx,
-            FMT_ENABLE_IF(std::is_same<
-                          ParseCtx, basic_printf_parse_context<Char>>::value)>
-  auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
 
   template <typename OutputIt>
   auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
       -> OutputIt {
-    basic_memory_buffer<Char> buffer;
+    auto buffer = basic_memory_buffer<Char>();
     format_value(buffer, value, ctx.locale());
-    basic_string_view<Char> str(buffer.data(), buffer.size());
+    return formatter<basic_string_view<Char>, Char>::format(
-    return formatter<basic_string_view<Char>, Char>::format(str, ctx);
+        {buffer.data(), buffer.size()}, ctx);
   }
+
+  // DEPRECATED!
   template <typename OutputIt>
   auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
       -> OutputIt {
-    basic_memory_buffer<Char> buffer;
+    auto buffer = basic_memory_buffer<Char>();
     format_value(buffer, value, ctx.locale());
     return std::copy(buffer.begin(), buffer.end(), ctx.out());
   }
@@ -155,7 +109,7 @@ FMT_MODULE_EXPORT
 template <typename Char>
 void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
             basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
+  auto buffer = basic_memory_buffer<Char>();
   detail::vformat_to(buffer, format_str, args);
   detail::write_buffer(os, buffer);
 }

include/fmt/printf.h

@@ -233,7 +233,7 @@ class printf_arg_formatter : public arg_formatter<Char> {
 
   OutputIt write_null_pointer(bool is_string = false) {
     auto s = this->specs;
-    s.type = 0;
+    s.type = presentation_type::none;
     return write_bytes(this->out, is_string ? "(null)" : "(nil)", s);
   }
 
@@ -249,8 +249,10 @@ class printf_arg_formatter : public arg_formatter<Char> {
     // std::is_same instead.
     if (std::is_same<T, Char>::value) {
       format_specs fmt_specs = this->specs;
-      if (fmt_specs.type && fmt_specs.type != 'c')
+      if (fmt_specs.type != presentation_type::none &&
+          fmt_specs.type != presentation_type::chr) {
         return (*this)(static_cast<int>(value));
+      }
       fmt_specs.sign = sign::none;
       fmt_specs.alt = false;
       fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
@@ -271,13 +273,13 @@ class printf_arg_formatter : public arg_formatter<Char> {
   /** Formats a null-terminated C string. */
   OutputIt operator()(const char* value) {
     if (value) return base::operator()(value);
-    return write_null_pointer(this->specs.type != 'p');
+    return write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
   /** Formats a null-terminated wide C string. */
   OutputIt operator()(const wchar_t* value) {
     if (value) return base::operator()(value);
-    return write_null_pointer(this->specs.type != 'p');
+    return write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
   OutputIt operator()(basic_string_view<Char> value) {
@@ -490,13 +492,13 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
 
     // Parse type.
     if (it == end) FMT_THROW(format_error("invalid format string"));
-    specs.type = static_cast<char>(*it++);
+    char type = static_cast<char>(*it++);
     if (arg.is_integral()) {
       // Normalize type.
-      switch (specs.type) {
+      switch (type) {
       case 'i':
       case 'u':
-        specs.type = 'd';
+        type = 'd';
         break;
       case 'c':
         visit_format_arg(
@@ -505,6 +507,9 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         break;
       }
     }
+    specs.type = parse_presentation_type(type);
+    if (specs.type == presentation_type::none)
+      parse_ctx.on_error("invalid type specifier");
 
     start = it;
 

include/fmt/ranges.h

@@ -13,37 +13,13 @@
 #define FMT_RANGES_H_
 
 #include <initializer_list>
+#include <tuple>
 #include <type_traits>
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-template <typename Char, typename Enable = void> struct formatting_range {
-#ifdef FMT_DEPRECATED_BRACED_RANGES
-  Char prefix = '{';
-  Char postfix = '}';
-#else
-  Char prefix = '[';
-  Char postfix = ']';
-#endif
-
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-};
-
-template <typename Char, typename Enable = void> struct formatting_tuple {
-  Char prefix = '(';
-  Char postfix = ')';
-
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-};
-
 namespace detail {
 
 template <typename RangeT, typename OutputIterator>
@@ -71,7 +47,7 @@ OutputIterator copy(wchar_t ch, OutputIterator out) {
   return out;
 }
 
-/// Return true value if T has std::string interface, like std::string_view.
+// Returns true if T has a std::string-like interface, like std::string_view.
 template <typename T> class is_std_string_like {
   template <typename U>
   static auto check(U* p)
@@ -80,12 +56,40 @@ template <typename T> class is_std_string_like {
 
  public:
   static FMT_CONSTEXPR_DECL const bool value =
-      is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value;
+      is_string<T>::value ||
+      std::is_convertible<T, std_string_view<char>>::value ||
+      !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 template <typename Char>
 struct is_std_string_like<fmt::basic_string_view<Char>> : std::true_type {};
 
+template <typename T> class is_map {
+  template <typename U> static auto check(U*) -> typename U::mapped_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_MAP_AS_LIST
+  static FMT_CONSTEXPR_DECL const bool value = false;
+#else
+  static FMT_CONSTEXPR_DECL const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+#endif
+};
+
+template <typename T> class is_set {
+  template <typename U> static auto check(U*) -> typename U::key_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_SET_AS_LIST
+  static FMT_CONSTEXPR_DECL const bool value = false;
+#else
+  static FMT_CONSTEXPR_DECL const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
+#endif
+};
+
 template <typename... Ts> struct conditional_helper {};
 
 template <typename T, typename _ = void> struct is_range_ : std::false_type {};
@@ -143,16 +147,16 @@ struct has_mutable_begin_end : std::false_type {};
 
 template <typename T>
 struct has_const_begin_end<
-    T, void_t<decltype(detail::range_begin(
+    T,
-                  std::declval<const remove_cvref_t<T>&>())),
+    void_t<
-              decltype(detail::range_begin(
+        decltype(detail::range_begin(std::declval<const remove_cvref_t<T>&>())),
-                  std::declval<const remove_cvref_t<T>&>()))>>
+        decltype(detail::range_end(std::declval<const remove_cvref_t<T>&>()))>>
     : std::true_type {};
 
 template <typename T>
 struct has_mutable_begin_end<
     T, void_t<decltype(detail::range_begin(std::declval<T>())),
-              decltype(detail::range_begin(std::declval<T>())),
+              decltype(detail::range_end(std::declval<T>())),
               enable_if_t<std::is_copy_constructible<T>::value>>>
     : std::true_type {};
 
@@ -160,34 +164,10 @@ template <typename T>
 struct is_range_<T, void>
     : std::integral_constant<bool, (has_const_begin_end<T>::value ||
                                     has_mutable_begin_end<T>::value)> {};
-
-template <typename T, typename Enable = void> struct range_to_view;
-template <typename T>
-struct range_to_view<T, enable_if_t<has_const_begin_end<T>::value>> {
-  struct view_t {
-    const T* m_range_ptr;
-
-    auto begin() const FMT_DECLTYPE_RETURN(detail::range_begin(*m_range_ptr));
-    auto end() const FMT_DECLTYPE_RETURN(detail::range_end(*m_range_ptr));
-  };
-  static auto view(const T& range) -> view_t { return {&range}; }
-};
-
-template <typename T>
-struct range_to_view<T, enable_if_t<!has_const_begin_end<T>::value &&
-                                    has_mutable_begin_end<T>::value>> {
-  struct view_t {
-    T m_range_copy;
-
-    auto begin() FMT_DECLTYPE_RETURN(detail::range_begin(m_range_copy));
-    auto end() FMT_DECLTYPE_RETURN(detail::range_end(m_range_copy));
-  };
-  static auto view(const T& range) -> view_t { return {range}; }
-};
 #  undef FMT_DECLTYPE_RETURN
 #endif
 
-/// tuple_size and tuple_element check.
+// tuple_size and tuple_element check.
 template <typename T> class is_tuple_like_ {
   template <typename U>
   static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
@@ -251,16 +231,295 @@ template <typename OutputIt> OutputIt write_delimiter(OutputIt out) {
   return out;
 }
 
-template <
+struct singleton {
-    typename Char, typename OutputIt, typename Arg,
+  unsigned char upper;
-    FMT_ENABLE_IF(is_std_string_like<typename std::decay<Arg>::type>::value)>
+  unsigned char lower_count;
-OutputIt write_range_entry(OutputIt out, const Arg& v) {
+};
+
+inline auto is_printable(uint16_t x, const singleton* singletons,
+                         size_t singletons_size,
+                         const unsigned char* singleton_lowers,
+                         const unsigned char* normal, size_t normal_size)
+    -> bool {
+  auto upper = x >> 8;
+  auto lower_start = 0;
+  for (size_t i = 0; i < singletons_size; ++i) {
+    auto s = singletons[i];
+    auto lower_end = lower_start + s.lower_count;
+    if (upper < s.upper) break;
+    if (upper == s.upper) {
+      for (auto j = lower_start; j < lower_end; ++j) {
+        if (singleton_lowers[j] == (x & 0xff)) return false;
+      }
+    }
+    lower_start = lower_end;
+  }
+
+  auto xsigned = static_cast<int>(x);
+  auto current = true;
+  for (size_t i = 0; i < normal_size; ++i) {
+    auto v = static_cast<int>(normal[i]);
+    auto len = (v & 0x80) != 0 ? (v & 0x7f) << 8 | normal[++i] : v;
+    xsigned -= len;
+    if (xsigned < 0) break;
+    current = !current;
+  }
+  return current;
+}
+
+// Returns true iff the code point cp is printable.
+// This code is generated by support/printable.py.
+inline auto is_printable(uint32_t cp) -> bool {
+  static constexpr singleton singletons0[] = {
+      {0x00, 1},  {0x03, 5},  {0x05, 6},  {0x06, 3},  {0x07, 6},  {0x08, 8},
+      {0x09, 17}, {0x0a, 28}, {0x0b, 25}, {0x0c, 20}, {0x0d, 16}, {0x0e, 13},
+      {0x0f, 4},  {0x10, 3},  {0x12, 18}, {0x13, 9},  {0x16, 1},  {0x17, 5},
+      {0x18, 2},  {0x19, 3},  {0x1a, 7},  {0x1c, 2},  {0x1d, 1},  {0x1f, 22},
+      {0x20, 3},  {0x2b, 3},  {0x2c, 2},  {0x2d, 11}, {0x2e, 1},  {0x30, 3},
+      {0x31, 2},  {0x32, 1},  {0xa7, 2},  {0xa9, 2},  {0xaa, 4},  {0xab, 8},
+      {0xfa, 2},  {0xfb, 5},  {0xfd, 4},  {0xfe, 3},  {0xff, 9},
+  };
+  static constexpr unsigned char singletons0_lower[] = {
+      0xad, 0x78, 0x79, 0x8b, 0x8d, 0xa2, 0x30, 0x57, 0x58, 0x8b, 0x8c, 0x90,
+      0x1c, 0x1d, 0xdd, 0x0e, 0x0f, 0x4b, 0x4c, 0xfb, 0xfc, 0x2e, 0x2f, 0x3f,
+      0x5c, 0x5d, 0x5f, 0xb5, 0xe2, 0x84, 0x8d, 0x8e, 0x91, 0x92, 0xa9, 0xb1,
+      0xba, 0xbb, 0xc5, 0xc6, 0xc9, 0xca, 0xde, 0xe4, 0xe5, 0xff, 0x00, 0x04,
+      0x11, 0x12, 0x29, 0x31, 0x34, 0x37, 0x3a, 0x3b, 0x3d, 0x49, 0x4a, 0x5d,
+      0x84, 0x8e, 0x92, 0xa9, 0xb1, 0xb4, 0xba, 0xbb, 0xc6, 0xca, 0xce, 0xcf,
+      0xe4, 0xe5, 0x00, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
+      0x3b, 0x45, 0x46, 0x49, 0x4a, 0x5e, 0x64, 0x65, 0x84, 0x91, 0x9b, 0x9d,
+      0xc9, 0xce, 0xcf, 0x0d, 0x11, 0x29, 0x45, 0x49, 0x57, 0x64, 0x65, 0x8d,
+      0x91, 0xa9, 0xb4, 0xba, 0xbb, 0xc5, 0xc9, 0xdf, 0xe4, 0xe5, 0xf0, 0x0d,
+      0x11, 0x45, 0x49, 0x64, 0x65, 0x80, 0x84, 0xb2, 0xbc, 0xbe, 0xbf, 0xd5,
+      0xd7, 0xf0, 0xf1, 0x83, 0x85, 0x8b, 0xa4, 0xa6, 0xbe, 0xbf, 0xc5, 0xc7,
+      0xce, 0xcf, 0xda, 0xdb, 0x48, 0x98, 0xbd, 0xcd, 0xc6, 0xce, 0xcf, 0x49,
+      0x4e, 0x4f, 0x57, 0x59, 0x5e, 0x5f, 0x89, 0x8e, 0x8f, 0xb1, 0xb6, 0xb7,
+      0xbf, 0xc1, 0xc6, 0xc7, 0xd7, 0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7,
+      0xfe, 0xff, 0x80, 0x0d, 0x6d, 0x71, 0xde, 0xdf, 0x0e, 0x0f, 0x1f, 0x6e,
+      0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e, 0xae, 0xaf, 0xbb, 0xbc, 0xfa, 0x16,
+      0x17, 0x1e, 0x1f, 0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c, 0x5e, 0x7e,
+      0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc, 0xf0, 0xf1, 0xf5, 0x72, 0x73, 0x8f,
+      0x74, 0x75, 0x96, 0x2f, 0x5f, 0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf,
+      0xc7, 0xcf, 0xd7, 0xdf, 0x9a, 0x40, 0x97, 0x98, 0x30, 0x8f, 0x1f, 0xc0,
+      0xc1, 0xce, 0xff, 0x4e, 0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27,
+      0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f, 0x42, 0x45, 0x90, 0x91,
+      0xfe, 0xff, 0x53, 0x67, 0x75, 0xc8, 0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7,
+      0xfe, 0xff,
+  };
+  static constexpr singleton singletons1[] = {
+      {0x00, 6},  {0x01, 1}, {0x03, 1},  {0x04, 2}, {0x08, 8},  {0x09, 2},
+      {0x0a, 5},  {0x0b, 2}, {0x0e, 4},  {0x10, 1}, {0x11, 2},  {0x12, 5},
+      {0x13, 17}, {0x14, 1}, {0x15, 2},  {0x17, 2}, {0x19, 13}, {0x1c, 5},
+      {0x1d, 8},  {0x24, 1}, {0x6a, 3},  {0x6b, 2}, {0xbc, 2},  {0xd1, 2},
+      {0xd4, 12}, {0xd5, 9}, {0xd6, 2},  {0xd7, 2}, {0xda, 1},  {0xe0, 5},
+      {0xe1, 2},  {0xe8, 2}, {0xee, 32}, {0xf0, 4}, {0xf8, 2},  {0xf9, 2},
+      {0xfa, 2},  {0xfb, 1},
+  };
+  static constexpr unsigned char singletons1_lower[] = {
+      0x0c, 0x27, 0x3b, 0x3e, 0x4e, 0x4f, 0x8f, 0x9e, 0x9e, 0x9f, 0x06, 0x07,
+      0x09, 0x36, 0x3d, 0x3e, 0x56, 0xf3, 0xd0, 0xd1, 0x04, 0x14, 0x18, 0x36,
+      0x37, 0x56, 0x57, 0x7f, 0xaa, 0xae, 0xaf, 0xbd, 0x35, 0xe0, 0x12, 0x87,
+      0x89, 0x8e, 0x9e, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
+      0x45, 0x46, 0x49, 0x4a, 0x4e, 0x4f, 0x64, 0x65, 0x5c, 0xb6, 0xb7, 0x1b,
+      0x1c, 0x07, 0x08, 0x0a, 0x0b, 0x14, 0x17, 0x36, 0x39, 0x3a, 0xa8, 0xa9,
+      0xd8, 0xd9, 0x09, 0x37, 0x90, 0x91, 0xa8, 0x07, 0x0a, 0x3b, 0x3e, 0x66,
+      0x69, 0x8f, 0x92, 0x6f, 0x5f, 0xee, 0xef, 0x5a, 0x62, 0x9a, 0x9b, 0x27,
+      0x28, 0x55, 0x9d, 0xa0, 0xa1, 0xa3, 0xa4, 0xa7, 0xa8, 0xad, 0xba, 0xbc,
+      0xc4, 0x06, 0x0b, 0x0c, 0x15, 0x1d, 0x3a, 0x3f, 0x45, 0x51, 0xa6, 0xa7,
+      0xcc, 0xcd, 0xa0, 0x07, 0x19, 0x1a, 0x22, 0x25, 0x3e, 0x3f, 0xc5, 0xc6,
+      0x04, 0x20, 0x23, 0x25, 0x26, 0x28, 0x33, 0x38, 0x3a, 0x48, 0x4a, 0x4c,
+      0x50, 0x53, 0x55, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x63, 0x65, 0x66,
+      0x6b, 0x73, 0x78, 0x7d, 0x7f, 0x8a, 0xa4, 0xaa, 0xaf, 0xb0, 0xc0, 0xd0,
+      0xae, 0xaf, 0x79, 0xcc, 0x6e, 0x6f, 0x93,
+  };
+  static constexpr unsigned char normal0[] = {
+      0x00, 0x20, 0x5f, 0x22, 0x82, 0xdf, 0x04, 0x82, 0x44, 0x08, 0x1b, 0x04,
+      0x06, 0x11, 0x81, 0xac, 0x0e, 0x80, 0xab, 0x35, 0x28, 0x0b, 0x80, 0xe0,
+      0x03, 0x19, 0x08, 0x01, 0x04, 0x2f, 0x04, 0x34, 0x04, 0x07, 0x03, 0x01,
+      0x07, 0x06, 0x07, 0x11, 0x0a, 0x50, 0x0f, 0x12, 0x07, 0x55, 0x07, 0x03,
+      0x04, 0x1c, 0x0a, 0x09, 0x03, 0x08, 0x03, 0x07, 0x03, 0x02, 0x03, 0x03,
+      0x03, 0x0c, 0x04, 0x05, 0x03, 0x0b, 0x06, 0x01, 0x0e, 0x15, 0x05, 0x3a,
+      0x03, 0x11, 0x07, 0x06, 0x05, 0x10, 0x07, 0x57, 0x07, 0x02, 0x07, 0x15,
+      0x0d, 0x50, 0x04, 0x43, 0x03, 0x2d, 0x03, 0x01, 0x04, 0x11, 0x06, 0x0f,
+      0x0c, 0x3a, 0x04, 0x1d, 0x25, 0x5f, 0x20, 0x6d, 0x04, 0x6a, 0x25, 0x80,
+      0xc8, 0x05, 0x82, 0xb0, 0x03, 0x1a, 0x06, 0x82, 0xfd, 0x03, 0x59, 0x07,
+      0x15, 0x0b, 0x17, 0x09, 0x14, 0x0c, 0x14, 0x0c, 0x6a, 0x06, 0x0a, 0x06,
+      0x1a, 0x06, 0x59, 0x07, 0x2b, 0x05, 0x46, 0x0a, 0x2c, 0x04, 0x0c, 0x04,
+      0x01, 0x03, 0x31, 0x0b, 0x2c, 0x04, 0x1a, 0x06, 0x0b, 0x03, 0x80, 0xac,
+      0x06, 0x0a, 0x06, 0x21, 0x3f, 0x4c, 0x04, 0x2d, 0x03, 0x74, 0x08, 0x3c,
+      0x03, 0x0f, 0x03, 0x3c, 0x07, 0x38, 0x08, 0x2b, 0x05, 0x82, 0xff, 0x11,
+      0x18, 0x08, 0x2f, 0x11, 0x2d, 0x03, 0x20, 0x10, 0x21, 0x0f, 0x80, 0x8c,
+      0x04, 0x82, 0x97, 0x19, 0x0b, 0x15, 0x88, 0x94, 0x05, 0x2f, 0x05, 0x3b,
+      0x07, 0x02, 0x0e, 0x18, 0x09, 0x80, 0xb3, 0x2d, 0x74, 0x0c, 0x80, 0xd6,
+      0x1a, 0x0c, 0x05, 0x80, 0xff, 0x05, 0x80, 0xdf, 0x0c, 0xee, 0x0d, 0x03,
+      0x84, 0x8d, 0x03, 0x37, 0x09, 0x81, 0x5c, 0x14, 0x80, 0xb8, 0x08, 0x80,
+      0xcb, 0x2a, 0x38, 0x03, 0x0a, 0x06, 0x38, 0x08, 0x46, 0x08, 0x0c, 0x06,
+      0x74, 0x0b, 0x1e, 0x03, 0x5a, 0x04, 0x59, 0x09, 0x80, 0x83, 0x18, 0x1c,
+      0x0a, 0x16, 0x09, 0x4c, 0x04, 0x80, 0x8a, 0x06, 0xab, 0xa4, 0x0c, 0x17,
+      0x04, 0x31, 0xa1, 0x04, 0x81, 0xda, 0x26, 0x07, 0x0c, 0x05, 0x05, 0x80,
+      0xa5, 0x11, 0x81, 0x6d, 0x10, 0x78, 0x28, 0x2a, 0x06, 0x4c, 0x04, 0x80,
+      0x8d, 0x04, 0x80, 0xbe, 0x03, 0x1b, 0x03, 0x0f, 0x0d,
+  };
+  static constexpr unsigned char normal1[] = {
+      0x5e, 0x22, 0x7b, 0x05, 0x03, 0x04, 0x2d, 0x03, 0x66, 0x03, 0x01, 0x2f,
+      0x2e, 0x80, 0x82, 0x1d, 0x03, 0x31, 0x0f, 0x1c, 0x04, 0x24, 0x09, 0x1e,
+      0x05, 0x2b, 0x05, 0x44, 0x04, 0x0e, 0x2a, 0x80, 0xaa, 0x06, 0x24, 0x04,
+      0x24, 0x04, 0x28, 0x08, 0x34, 0x0b, 0x01, 0x80, 0x90, 0x81, 0x37, 0x09,
+      0x16, 0x0a, 0x08, 0x80, 0x98, 0x39, 0x03, 0x63, 0x08, 0x09, 0x30, 0x16,
+      0x05, 0x21, 0x03, 0x1b, 0x05, 0x01, 0x40, 0x38, 0x04, 0x4b, 0x05, 0x2f,
+      0x04, 0x0a, 0x07, 0x09, 0x07, 0x40, 0x20, 0x27, 0x04, 0x0c, 0x09, 0x36,
+      0x03, 0x3a, 0x05, 0x1a, 0x07, 0x04, 0x0c, 0x07, 0x50, 0x49, 0x37, 0x33,
+      0x0d, 0x33, 0x07, 0x2e, 0x08, 0x0a, 0x81, 0x26, 0x52, 0x4e, 0x28, 0x08,
+      0x2a, 0x56, 0x1c, 0x14, 0x17, 0x09, 0x4e, 0x04, 0x1e, 0x0f, 0x43, 0x0e,
+      0x19, 0x07, 0x0a, 0x06, 0x48, 0x08, 0x27, 0x09, 0x75, 0x0b, 0x3f, 0x41,
+      0x2a, 0x06, 0x3b, 0x05, 0x0a, 0x06, 0x51, 0x06, 0x01, 0x05, 0x10, 0x03,
+      0x05, 0x80, 0x8b, 0x62, 0x1e, 0x48, 0x08, 0x0a, 0x80, 0xa6, 0x5e, 0x22,
+      0x45, 0x0b, 0x0a, 0x06, 0x0d, 0x13, 0x39, 0x07, 0x0a, 0x36, 0x2c, 0x04,
+      0x10, 0x80, 0xc0, 0x3c, 0x64, 0x53, 0x0c, 0x48, 0x09, 0x0a, 0x46, 0x45,
+      0x1b, 0x48, 0x08, 0x53, 0x1d, 0x39, 0x81, 0x07, 0x46, 0x0a, 0x1d, 0x03,
+      0x47, 0x49, 0x37, 0x03, 0x0e, 0x08, 0x0a, 0x06, 0x39, 0x07, 0x0a, 0x81,
+      0x36, 0x19, 0x80, 0xb7, 0x01, 0x0f, 0x32, 0x0d, 0x83, 0x9b, 0x66, 0x75,
+      0x0b, 0x80, 0xc4, 0x8a, 0xbc, 0x84, 0x2f, 0x8f, 0xd1, 0x82, 0x47, 0xa1,
+      0xb9, 0x82, 0x39, 0x07, 0x2a, 0x04, 0x02, 0x60, 0x26, 0x0a, 0x46, 0x0a,
+      0x28, 0x05, 0x13, 0x82, 0xb0, 0x5b, 0x65, 0x4b, 0x04, 0x39, 0x07, 0x11,
+      0x40, 0x05, 0x0b, 0x02, 0x0e, 0x97, 0xf8, 0x08, 0x84, 0xd6, 0x2a, 0x09,
+      0xa2, 0xf7, 0x81, 0x1f, 0x31, 0x03, 0x11, 0x04, 0x08, 0x81, 0x8c, 0x89,
+      0x04, 0x6b, 0x05, 0x0d, 0x03, 0x09, 0x07, 0x10, 0x93, 0x60, 0x80, 0xf6,
+      0x0a, 0x73, 0x08, 0x6e, 0x17, 0x46, 0x80, 0x9a, 0x14, 0x0c, 0x57, 0x09,
+      0x19, 0x80, 0x87, 0x81, 0x47, 0x03, 0x85, 0x42, 0x0f, 0x15, 0x85, 0x50,
+      0x2b, 0x80, 0xd5, 0x2d, 0x03, 0x1a, 0x04, 0x02, 0x81, 0x70, 0x3a, 0x05,
+      0x01, 0x85, 0x00, 0x80, 0xd7, 0x29, 0x4c, 0x04, 0x0a, 0x04, 0x02, 0x83,
+      0x11, 0x44, 0x4c, 0x3d, 0x80, 0xc2, 0x3c, 0x06, 0x01, 0x04, 0x55, 0x05,
+      0x1b, 0x34, 0x02, 0x81, 0x0e, 0x2c, 0x04, 0x64, 0x0c, 0x56, 0x0a, 0x80,
+      0xae, 0x38, 0x1d, 0x0d, 0x2c, 0x04, 0x09, 0x07, 0x02, 0x0e, 0x06, 0x80,
+      0x9a, 0x83, 0xd8, 0x08, 0x0d, 0x03, 0x0d, 0x03, 0x74, 0x0c, 0x59, 0x07,
+      0x0c, 0x14, 0x0c, 0x04, 0x38, 0x08, 0x0a, 0x06, 0x28, 0x08, 0x22, 0x4e,
+      0x81, 0x54, 0x0c, 0x15, 0x03, 0x03, 0x05, 0x07, 0x09, 0x19, 0x07, 0x07,
+      0x09, 0x03, 0x0d, 0x07, 0x29, 0x80, 0xcb, 0x25, 0x0a, 0x84, 0x06,
+  };
+  auto lower = static_cast<uint16_t>(cp);
+  if (cp < 0x10000) {
+    return is_printable(lower, singletons0,
+                        sizeof(singletons0) / sizeof(*singletons0),
+                        singletons0_lower, normal0, sizeof(normal0));
+  }
+  if (cp < 0x20000) {
+    return is_printable(lower, singletons1,
+                        sizeof(singletons1) / sizeof(*singletons1),
+                        singletons1_lower, normal1, sizeof(normal1));
+  }
+  if (0x2a6de <= cp && cp < 0x2a700) return false;
+  if (0x2b735 <= cp && cp < 0x2b740) return false;
+  if (0x2b81e <= cp && cp < 0x2b820) return false;
+  if (0x2cea2 <= cp && cp < 0x2ceb0) return false;
+  if (0x2ebe1 <= cp && cp < 0x2f800) return false;
+  if (0x2fa1e <= cp && cp < 0x30000) return false;
+  if (0x3134b <= cp && cp < 0xe0100) return false;
+  if (0xe01f0 <= cp && cp < 0x110000) return false;
+  return cp < 0x110000;
+}
+
+inline auto needs_escape(uint32_t cp) -> bool {
+  return cp < 0x20 || cp == 0x7f || cp == '"' || cp == '\\' ||
+         !is_printable(cp);
+}
+
+template <typename Char> struct find_escape_result {
+  const Char* begin;
+  const Char* end;
+  uint32_t cp;
+};
+
+template <typename Char>
+auto find_escape(const Char* begin, const Char* end)
+    -> find_escape_result<Char> {
+  for (; begin != end; ++begin) {
+    auto cp = static_cast<typename std::make_unsigned<Char>::type>(*begin);
+    if (sizeof(Char) == 1 && cp >= 0x80) continue;
+    if (needs_escape(cp)) return {begin, begin + 1, cp};
+  }
+  return {begin, nullptr, 0};
+}
+
+inline auto find_escape(const char* begin, const char* end)
+    -> find_escape_result<char> {
+  if (!is_utf8()) return find_escape<char>(begin, end);
+  auto result = find_escape_result<char>{end, nullptr, 0};
+  for_each_codepoint(string_view(begin, to_unsigned(end - begin)),
+                     [&](uint32_t cp, string_view sv) {
+                       if (needs_escape(cp)) {
+                         result = {sv.begin(), sv.end(), cp};
+                         return false;
+                       }
+                       return true;
+                     });
+  return result;
+}
+
+template <typename Char, typename OutputIt>
+auto write_range_entry(OutputIt out, basic_string_view<Char> str) -> OutputIt {
   *out++ = '"';
-  out = write<Char>(out, v);
+  auto begin = str.begin(), end = str.end();
+  do {
+    auto escape = find_escape(begin, end);
+    out = copy_str<Char>(begin, escape.begin, out);
+    begin = escape.end;
+    if (!begin) break;
+    auto c = static_cast<Char>(escape.cp);
+    switch (escape.cp) {
+    case '\n':
+      *out++ = '\\';
+      c = 'n';
+      break;
+    case '\r':
+      *out++ = '\\';
+      c = 'r';
+      break;
+    case '\t':
+      *out++ = '\\';
+      c = 't';
+      break;
+    case '"':
+      FMT_FALLTHROUGH;
+    case '\\':
+      *out++ = '\\';
+      break;
+    default:
+      if (is_utf8()) {
+        if (escape.cp < 0x100) {
+          out = format_to(out, "\\x{:02x}", escape.cp);
+          continue;
+        }
+        if (escape.cp < 0x10000) {
+          out = format_to(out, "\\u{:04x}", escape.cp);
+          continue;
+        }
+        if (escape.cp < 0x110000) {
+          out = format_to(out, "\\U{:08x}", escape.cp);
+          continue;
+        }
+      }
+      for (Char escape_char : basic_string_view<Char>(
+               escape.begin, to_unsigned(escape.end - escape.begin))) {
+        out = format_to(
+            out, "\\x{:02x}",
+            static_cast<typename std::make_unsigned<Char>::type>(escape_char));
+      }
+      continue;
+    }
+    *out++ = c;
+  } while (begin != end);
   *out++ = '"';
   return out;
 }
 
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(std::is_convertible<T, std_string_view<char>>::value)>
+inline auto write_range_entry(OutputIt out, const T& str) -> OutputIt {
+  auto sv = std_string_view<Char>(str);
+  return write_range_entry<Char>(out, basic_string_view<Char>(sv));
+}
+
 template <typename Char, typename OutputIt, typename Arg,
           FMT_ENABLE_IF(std::is_same<Arg, Char>::value)>
 OutputIt write_range_entry(OutputIt out, const Arg v) {
@@ -288,43 +547,37 @@ template <typename T> struct is_tuple_like {
 template <typename TupleT, typename Char>
 struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
  private:
-  // C++11 generic lambda for format()
+  // C++11 generic lambda for format().
   template <typename FormatContext> struct format_each {
     template <typename T> void operator()(const T& v) {
       if (i > 0) out = detail::write_delimiter(out);
       out = detail::write_range_entry<Char>(out, v);
       ++i;
     }
-    formatting_tuple<Char>& formatting;
+    int i;
-    size_t& i;
+    typename FormatContext::iterator& out;
-    typename std::add_lvalue_reference<
-        decltype(std::declval<FormatContext>().out())>::type out;
   };
 
  public:
-  formatting_tuple<Char> formatting;
-
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+    return ctx.begin();
   }
 
   template <typename FormatContext = format_context>
   auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
     auto out = ctx.out();
-    size_t i = 0;
+    *out++ = '(';
-
+    detail::for_each(values, format_each<FormatContext>{0, out});
-    detail::copy(formatting.prefix, out);
+    *out++ = ')';
-    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
+    return out;
-    detail::copy(formatting.postfix, out);
-
-    return ctx.out();
   }
 };
 
 template <typename T, typename Char> struct is_range {
   static FMT_CONSTEXPR_DECL const bool value =
       detail::is_range_<T>::value && !detail::is_std_string_like<T>::value &&
+      !detail::is_map<T>::value &&
       !std::is_convertible<T, std::basic_string<Char>>::value &&
       !std::is_constructible<detail::std_string_view<Char>, T>::value;
 };
@@ -334,32 +587,80 @@ struct formatter<
     T, Char,
     enable_if_t<
         fmt::is_range<T, Char>::value
-// Workaround a bug in MSVC 2017 and earlier.
+// Workaround a bug in MSVC 2019 and earlier.
-#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
+#if !FMT_MSC_VER
-        && (has_formatter<detail::value_type<T>, format_context>::value ||
+        && (is_formattable<detail::value_type<T>, Char>::value ||
             detail::has_fallback_formatter<detail::value_type<T>, Char>::value)
 #endif
         >> {
-  formatting_range<Char> formatting;
-
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+    return ctx.begin();
   }
 
-  template <typename FormatContext>
+  template <
-  typename FormatContext::iterator format(const T& values, FormatContext& ctx) {
+      typename FormatContext, typename U,
-    auto out = detail::copy(formatting.prefix, ctx.out());
+      FMT_ENABLE_IF(
-    size_t i = 0;
+          std::is_same<U, conditional_t<detail::has_const_begin_end<T>::value,
-    auto view = detail::range_to_view<T>::view(values);
+                                        const T, T>>::value)>
-    auto it = view.begin();
+  auto format(U& range, FormatContext& ctx) -> decltype(ctx.out()) {
-    auto end = view.end();
+#ifdef FMT_DEPRECATED_BRACED_RANGES
+    Char prefix = '{';
+    Char postfix = '}';
+#else
+    Char prefix = detail::is_set<T>::value ? '{' : '[';
+    Char postfix = detail::is_set<T>::value ? '}' : ']';
+#endif
+    auto out = ctx.out();
+    *out++ = prefix;
+    int i = 0;
+    auto it = std::begin(range);
+    auto end = std::end(range);
     for (; it != end; ++it) {
       if (i > 0) out = detail::write_delimiter(out);
       out = detail::write_range_entry<Char>(out, *it);
       ++i;
     }
-    return detail::copy(formatting.postfix, out);
+    *out++ = postfix;
+    return out;
+  }
+};
+
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    enable_if_t<
+        detail::is_map<T>::value
+// Workaround a bug in MSVC 2019 and earlier.
+#if !FMT_MSC_VER
+        && (is_formattable<detail::value_type<T>, Char>::value ||
+            detail::has_fallback_formatter<detail::value_type<T>, Char>::value)
+#endif
+        >> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <
+      typename FormatContext, typename U,
+      FMT_ENABLE_IF(
+          std::is_same<U, conditional_t<detail::has_const_begin_end<T>::value,
+                                        const T, T>>::value)>
+  auto format(U& map, FormatContext& ctx) -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    *out++ = '{';
+    int i = 0;
+    for (const auto& item : map) {
+      if (i > 0) out = detail::write_delimiter(out);
+      out = detail::write_range_entry<Char>(out, item.first);
+      *out++ = ':';
+      *out++ = ' ';
+      out = detail::write_range_entry<Char>(out, item.second);
+      ++i;
+    }
+    *out++ = '}';
+    return out;
   }
 };
 
@@ -374,45 +675,70 @@ template <typename Char, typename... T> struct tuple_join_view : detail::view {
 template <typename Char, typename... T>
 using tuple_arg_join = tuple_join_view<Char, T...>;
 
+// Define FMT_TUPLE_JOIN_SPECIFIERS to enable experimental format specifiers
+// support in tuple_join. It is disabled by default because of issues with
+// the dynamic width and precision.
+#ifndef FMT_TUPLE_JOIN_SPECIFIERS
+#  define FMT_TUPLE_JOIN_SPECIFIERS 0
+#endif
+
 template <typename Char, typename... T>
 struct formatter<tuple_join_view<Char, T...>, Char> {
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    return do_parse(ctx, std::integral_constant<size_t, sizeof...(T)>());
   }
 
   template <typename FormatContext>
-  auto format(const tuple_join_view<Char, T...>& value, FormatContext& ctx) ->
+  auto format(const tuple_join_view<Char, T...>& value,
-      typename FormatContext::iterator {
+              FormatContext& ctx) const -> typename FormatContext::iterator {
-    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
+    return do_format(value, ctx,
+                     std::integral_constant<size_t, sizeof...(T)>());
   }
 
  private:
-  template <typename FormatContext, size_t... N>
+  std::tuple<formatter<typename std::decay<T>::type, Char>...> formatters_;
-  auto format(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
+
-              detail::index_sequence<N...>) ->
+  template <typename ParseContext>
-      typename FormatContext::iterator {
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
-    return format_args(value, ctx, std::get<N>(value.tuple)...);
+                              std::integral_constant<size_t, 0>)
+      -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename ParseContext, size_t N>
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+                              std::integral_constant<size_t, N>)
+      -> decltype(ctx.begin()) {
+    auto end = ctx.begin();
+#if FMT_TUPLE_JOIN_SPECIFIERS
+    end = std::get<sizeof...(T) - N>(formatters_).parse(ctx);
+    if (N > 1) {
+      auto end1 = do_parse(ctx, std::integral_constant<size_t, N - 1>());
+      if (end != end1)
+        FMT_THROW(format_error("incompatible format specs for tuple elements"));
+    }
+#endif
+    return end;
   }
 
   template <typename FormatContext>
-  auto format_args(const tuple_join_view<Char, T...>&, FormatContext& ctx) ->
+  auto do_format(const tuple_join_view<Char, T...>&, FormatContext& ctx,
+                 std::integral_constant<size_t, 0>) const ->
       typename FormatContext::iterator {
-    // NOTE: for compilers that support C++17, this empty function instantiation
-    // can be replaced with a constexpr branch in the variadic overload.
     return ctx.out();
   }
 
-  template <typename FormatContext, typename Arg, typename... Args>
+  template <typename FormatContext, size_t N>
-  auto format_args(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
+  auto do_format(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
-                   const Arg& arg, const Args&... args) ->
+                 std::integral_constant<size_t, N>) const ->
       typename FormatContext::iterator {
-    using base = formatter<typename std::decay<Arg>::type, Char>;
+    auto out = std::get<sizeof...(T) - N>(formatters_)
-    auto out = base().format(arg, ctx);
+                   .format(std::get<sizeof...(T) - N>(value.tuple), ctx);
-    if (sizeof...(Args) > 0) {
+    if (N > 1) {
       out = std::copy(value.sep.begin(), value.sep.end(), out);
       ctx.advance_to(out);
-      return format_args(value, ctx, args...);
+      return do_format(value, ctx, std::integral_constant<size_t, N - 1>());
     }
     return out;
   }

include/fmt/xchar.h

@@ -5,8 +5,8 @@
 //
 // For the license information refer to format.h.
 
-#ifndef FMT_WCHAR_H_
+#ifndef FMT_XCHAR_H_
-#define FMT_WCHAR_H_
+#define FMT_XCHAR_H_
 
 #include <cwchar>
 #include <tuple>
@@ -142,7 +142,7 @@ FMT_DEPRECATED auto format_to(basic_memory_buffer<Char, SIZE, Allocator>& buf,
                               const S& format_str, Args&&... args) ->
     typename buffer_context<Char>::iterator {
   const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
-  detail::vformat_to(buf, to_string_view(format_str), vargs);
+  detail::vformat_to(buf, to_string_view(format_str), vargs, {});
   return detail::buffer_appender<Char>(buf);
 }
 
@@ -217,11 +217,11 @@ inline void vprint(wstring_view fmt, wformat_args args) {
 
 template <typename... T>
 void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
-  return vprint(f, wstring_view(fmt), make_wformat_args(args...));
+  return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
 }
 
 template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
-  return vprint(wstring_view(fmt), make_wformat_args(args...));
+  return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
 }
 
 /**
@@ -233,4 +233,4 @@ template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
 FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
-#endif  // FMT_WCHAR_H_
+#endif  // FMT_XCHAR_H_

src/fmt.cc

@@ -79,7 +79,6 @@ export module fmt;
 #define FMT_END_DETAIL_NAMESPACE \
   }                              \
   export {
-
 // all library-provided declarations and definitions
 // must be in the module purview to be exported
 #include "fmt/args.h"

src/format.cc

@@ -10,6 +10,52 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
+// DEPRECATED!
+template <typename T = void> struct basic_data {
+  FMT_API static constexpr const char digits[100][2] = {
+      {'0', '0'}, {'0', '1'}, {'0', '2'}, {'0', '3'}, {'0', '4'}, {'0', '5'},
+      {'0', '6'}, {'0', '7'}, {'0', '8'}, {'0', '9'}, {'1', '0'}, {'1', '1'},
+      {'1', '2'}, {'1', '3'}, {'1', '4'}, {'1', '5'}, {'1', '6'}, {'1', '7'},
+      {'1', '8'}, {'1', '9'}, {'2', '0'}, {'2', '1'}, {'2', '2'}, {'2', '3'},
+      {'2', '4'}, {'2', '5'}, {'2', '6'}, {'2', '7'}, {'2', '8'}, {'2', '9'},
+      {'3', '0'}, {'3', '1'}, {'3', '2'}, {'3', '3'}, {'3', '4'}, {'3', '5'},
+      {'3', '6'}, {'3', '7'}, {'3', '8'}, {'3', '9'}, {'4', '0'}, {'4', '1'},
+      {'4', '2'}, {'4', '3'}, {'4', '4'}, {'4', '5'}, {'4', '6'}, {'4', '7'},
+      {'4', '8'}, {'4', '9'}, {'5', '0'}, {'5', '1'}, {'5', '2'}, {'5', '3'},
+      {'5', '4'}, {'5', '5'}, {'5', '6'}, {'5', '7'}, {'5', '8'}, {'5', '9'},
+      {'6', '0'}, {'6', '1'}, {'6', '2'}, {'6', '3'}, {'6', '4'}, {'6', '5'},
+      {'6', '6'}, {'6', '7'}, {'6', '8'}, {'6', '9'}, {'7', '0'}, {'7', '1'},
+      {'7', '2'}, {'7', '3'}, {'7', '4'}, {'7', '5'}, {'7', '6'}, {'7', '7'},
+      {'7', '8'}, {'7', '9'}, {'8', '0'}, {'8', '1'}, {'8', '2'}, {'8', '3'},
+      {'8', '4'}, {'8', '5'}, {'8', '6'}, {'8', '7'}, {'8', '8'}, {'8', '9'},
+      {'9', '0'}, {'9', '1'}, {'9', '2'}, {'9', '3'}, {'9', '4'}, {'9', '5'},
+      {'9', '6'}, {'9', '7'}, {'9', '8'}, {'9', '9'}};
+  FMT_API static constexpr const char hex_digits[] = "0123456789abcdef";
+  FMT_API static constexpr const char signs[4] = {0, '-', '+', ' '};
+  FMT_API static constexpr const char left_padding_shifts[5] = {31, 31, 0, 1,
+                                                                0};
+  FMT_API static constexpr const char right_padding_shifts[5] = {0, 31, 0, 1,
+                                                                 0};
+  FMT_API static constexpr const unsigned prefixes[4] = {0, 0, 0x1000000u | '+',
+                                                         0x1000000u | ' '};
+};
+
+#ifdef FMT_SHARED
+// Required for -flto, -fivisibility=hidden and -shared to work
+extern template struct basic_data<void>;
+#endif
+
+#if __cplusplus < 201703L
+// DEPRECATED! These are here only for ABI compatiblity.
+template <typename T> constexpr const char basic_data<T>::digits[][2];
+template <typename T> constexpr const char basic_data<T>::hex_digits[];
+template <typename T> constexpr const char basic_data<T>::signs[];
+template <typename T> constexpr const char basic_data<T>::left_padding_shifts[];
+template <typename T>
+constexpr const char basic_data<T>::right_padding_shifts[];
+template <typename T> constexpr const unsigned basic_data<T>::prefixes[];
+#endif
+
 template <typename T>
 int format_float(char* buf, std::size_t size, const char* format, int precision,
                  T value) {
@@ -47,6 +93,9 @@ template FMT_API char detail::decimal_point_impl(locale_ref);
 
 template FMT_API void detail::buffer<char>::append(const char*, const char*);
 
+// DEPRECATED!
+// There is no correspondent extern template in format.h because of
+// incompatibility between clang and gcc (#2377).
 template FMT_API void detail::vformat_to(
     detail::buffer<char>&, string_view,
     basic_format_args<FMT_BUFFER_CONTEXT(char)>, detail::locale_ref);

src/os.cc

@@ -26,19 +26,17 @@
 #    endif
 #    include <io.h>
 
-#    define O_CREAT _O_CREAT
-#    define O_TRUNC _O_TRUNC
-
 #    ifndef S_IRUSR
 #      define S_IRUSR _S_IREAD
 #    endif
-
 #    ifndef S_IWUSR
 #      define S_IWUSR _S_IWRITE
 #    endif
-
+#    ifndef S_IRGRP
-#    ifdef __MINGW32__
+#      define S_IRGRP 0
-#      define _SH_DENYNO 0x40
+#    endif
+#    ifndef S_IROTH
+#      define S_IROTH 0
 #    endif
 #  endif  // _WIN32
 #endif    // FMT_USE_FCNTL
@@ -213,7 +211,10 @@ int buffered_file::fileno() const {
 
 #if FMT_USE_FCNTL
 file::file(cstring_view path, int oflag) {
-  int mode = S_IRUSR | S_IWUSR;
+#  ifdef _WIN32
+  using mode_t = int;
+#  endif
+  mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
 #  if defined(_WIN32) && !defined(__MINGW32__)
   fd_ = -1;
   FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));

support/bazel/.bazelrc

@@ -0,0 +1 @@
+build --symlink_prefix=/ # Out of source build

support/bazel/.bazelversion

@@ -0,0 +1 @@
+4.2.1

support/bazel/BUILD.bazel

@@ -0,0 +1,29 @@
+cc_library(
+    name = "fmt",
+    srcs = [
+        #"src/fmt.cc", # No C++ module support
+        "src/format.cc",
+        "src/os.cc",
+    ],
+    hdrs = [
+        "include/fmt/args.h",
+        "include/fmt/chrono.h",
+        "include/fmt/color.h",
+        "include/fmt/compile.h",
+        "include/fmt/core.h",
+        "include/fmt/format.h",
+        "include/fmt/format-inl.h",
+        "include/fmt/locale.h",
+        "include/fmt/os.h",
+        "include/fmt/ostream.h",
+        "include/fmt/printf.h",
+        "include/fmt/ranges.h",
+        "include/fmt/xchar.h",
+    ],
+    includes = [
+        "include",
+        "src",
+    ],
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)

support/bazel/README.md

@@ -0,0 +1,73 @@
+# Bazel support
+
+To get [Bazel](https://bazel.build/) working with {fmt} you can copy the files `BUILD.bazel`, `WORKSPACE.bazel`, `.bazelrc`, and `.bazelversion` from this folder (`support/bazel`) to the root folder of this project. This way {fmt} gets bazelized and can be used with Bazel (e.g. doing a `bazel build //...` on {fmt}). 
+
+## Using {fmt} as a dependency
+
+The following minimal example shows how to use {fmt} as a dependency within a Bazel project.
+
+The following file structure is assumed:
+
+```
+example
+├── BUILD.bazel
+├── main.cpp
+└── WORKSPACE.bazel
+```
+
+*main.cpp*:
+
+```c++
+#include "fmt/core.h"
+
+int main() {
+  fmt::print("The answer is {}\n", 42);
+}
+```
+
+The expected output of this example is `The answer is 42`.
+
+*WORKSPACE.bazel*:
+
+```python
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+
+git_repository(
+    name = "fmt",
+    branch = "master",
+    remote = "https://github.com/fmtlib/fmt",
+    patch_cmds = [
+        "mv support/bazel/.bazelrc .bazelrc",
+        "mv support/bazel/.bazelversion .bazelversion",
+        "mv support/bazel/BUILD.bazel BUILD.bazel",
+        "mv support/bazel/WORKSPACE.bazel WORKSPACE.bazel",
+    ],
+    # Windows-related patch commands are only needed in the case MSYS2 is not installed.
+    # More details about the installation process of MSYS2 on Windows systems can be found here:
+    # https://docs.bazel.build/versions/main/install-windows.html#installing-compilers-and-language-runtimes
+    # Even if MSYS2 is installed the Windows related patch commands can still be used.
+    patch_cmds_win = [
+        "Move-Item -Path support/bazel/.bazelrc -Destination .bazelrc",
+        "Move-Item -Path support/bazel/.bazelversion -Destination .bazelversion",
+        "Move-Item -Path support/bazel/BUILD.bazel -Destination BUILD.bazel",
+        "Move-Item -Path support/bazel/WORKSPACE.bazel -Destination WORKSPACE.bazel",
+    ],
+)
+```
+
+In the *WORKSPACE* file, the {fmt} GitHub repository is fetched. Using the attribute `patch_cmds` the  files `BUILD.bazel`, `WORKSPACE.bazel`, `.bazelrc`, and `.bazelversion` are moved to the root of the {fmt} repository. This way the {fmt} repository is recognized as a bazelized workspace. 
+
+*BUILD.bazel*:
+
+```python
+cc_binary(
+    name = "Demo",
+    srcs = ["main.cpp"],
+    deps = ["@fmt"],
+)
+```
+
+The *BUILD* file defines a binary named `Demo` that has a dependency to {fmt}.
+
+To execute the binary you can run `bazel run //:Demo`.
+

support/bazel/WORKSPACE.bazel

@@ -0,0 +1 @@
+workspace(name = "fmt")

support/manage.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Manage site and releases.
 
@@ -163,6 +163,13 @@ def update_site(env):
                 if version.startswith('7.'):
                     b.data = b.data.replace(', std::size_t', ', size_t')
                     b.data = b.data.replace('join(It, It', 'join(It, Sentinel')
+                if version.startswith('7.1.'):
+                    b.data = b.data.replace(', std::size_t', ', size_t')
+                    b.data = b.data.replace('join(It, It', 'join(It, Sentinel')
+                    b.data = b.data.replace(
+                        'fmt::format_to(OutputIt, const S&, Args&&...)',
+                        'fmt::format_to(OutputIt, const S&, Args&&...) -> ' +
+                        'typename std::enable_if<enable, OutputIt>::type')
                 b.data = b.data.replace('aa long', 'a long')
                 b.data = b.data.replace('serveral', 'several')
                 if version.startswith('6.2.'):
@@ -233,7 +240,7 @@ def release(args):
     # Update the version in the changelog.
     title_len = 0
     for line in fileinput.input(changelog_path, inplace=True):
-        if line.decode('utf-8').startswith(version + ' - TBD'):
+        if line.startswith(version + ' - TBD'):
             line = version + ' - ' + datetime.date.today().isoformat()
             title_len = len(line)
             line += '\n'
@@ -263,9 +270,9 @@ def release(args):
 
     # Create a release on GitHub.
     fmt_repo.push('origin', 'release')
-    params = {'access_token': os.getenv('FMT_TOKEN')}
+    auth_headers = {'Authorization': 'token ' + os.getenv('FMT_TOKEN')}
     r = requests.post('https://api.github.com/repos/fmtlib/fmt/releases',
-                      params=params,
+                      headers=auth_headers,
                       data=json.dumps({'tag_name': version,
                                        'target_commitish': 'release',
                                        'body': changes, 'draft': True}))
@@ -276,8 +283,8 @@ def release(args):
     package = 'fmt-{}.zip'.format(version)
     r = requests.post(
         '{}/{}/assets?name={}'.format(uploads_url, id, package),
-        headers={'Content-Type': 'application/zip'},
+        headers={'Content-Type': 'application/zip'} | auth_headers,
-        params=params, data=open('build/fmt/' + package, 'rb'))
+        data=open('build/fmt/' + package, 'rb'))
     if r.status_code != 201:
         raise Exception('Failed to upload an asset ' + str(r))
 

support/printable.py

@@ -0,0 +1,201 @@
+#!/usr/bin/env python3
+
+# This script is based on
+# https://github.com/rust-lang/rust/blob/master/library/core/src/unicode/printable.py
+# distributed under https://github.com/rust-lang/rust/blob/master/LICENSE-MIT.
+
+# This script uses the following Unicode tables:
+# - UnicodeData.txt
+
+
+from collections import namedtuple
+import csv
+import os
+import subprocess
+
+NUM_CODEPOINTS=0x110000
+
+def to_ranges(iter):
+    current = None
+    for i in iter:
+        if current is None or i != current[1] or i in (0x10000, 0x20000):
+            if current is not None:
+                yield tuple(current)
+            current = [i, i + 1]
+        else:
+            current[1] += 1
+    if current is not None:
+        yield tuple(current)
+
+def get_escaped(codepoints):
+    for c in codepoints:
+        if (c.class_ or "Cn") in "Cc Cf Cs Co Cn Zl Zp Zs".split() and c.value != ord(' '):
+            yield c.value
+
+def get_file(f):
+    try:
+        return open(os.path.basename(f))
+    except FileNotFoundError:
+        subprocess.run(["curl", "-O", f], check=True)
+        return open(os.path.basename(f))
+
+Codepoint = namedtuple('Codepoint', 'value class_')
+
+def get_codepoints(f):
+    r = csv.reader(f, delimiter=";")
+    prev_codepoint = 0
+    class_first = None
+    for row in r:
+        codepoint = int(row[0], 16)
+        name = row[1]
+        class_ = row[2]
+
+        if class_first is not None:
+            if not name.endswith("Last>"):
+                raise ValueError("Missing Last after First")
+
+        for c in range(prev_codepoint + 1, codepoint):
+            yield Codepoint(c, class_first)
+
+        class_first = None
+        if name.endswith("First>"):
+            class_first = class_
+
+        yield Codepoint(codepoint, class_)
+        prev_codepoint = codepoint
+
+    if class_first is not None:
+        raise ValueError("Missing Last after First")
+
+    for c in range(prev_codepoint + 1, NUM_CODEPOINTS):
+        yield Codepoint(c, None)
+
+def compress_singletons(singletons):
+    uppers = [] # (upper, # items in lowers)
+    lowers = []
+
+    for i in singletons:
+        upper = i >> 8
+        lower = i & 0xff
+        if len(uppers) == 0 or uppers[-1][0] != upper:
+            uppers.append((upper, 1))
+        else:
+            upper, count = uppers[-1]
+            uppers[-1] = upper, count + 1
+        lowers.append(lower)
+
+    return uppers, lowers
+
+def compress_normal(normal):
+    # lengths 0x00..0x7f are encoded as 00, 01, ..., 7e, 7f
+    # lengths 0x80..0x7fff are encoded as 80 80, 80 81, ..., ff fe, ff ff
+    compressed = [] # [truelen, (truelenaux), falselen, (falselenaux)]
+
+    prev_start = 0
+    for start, count in normal:
+        truelen = start - prev_start
+        falselen = count
+        prev_start = start + count
+
+        assert truelen < 0x8000 and falselen < 0x8000
+        entry = []
+        if truelen > 0x7f:
+            entry.append(0x80 | (truelen >> 8))
+            entry.append(truelen & 0xff)
+        else:
+            entry.append(truelen & 0x7f)
+        if falselen > 0x7f:
+            entry.append(0x80 | (falselen >> 8))
+            entry.append(falselen & 0xff)
+        else:
+            entry.append(falselen & 0x7f)
+
+        compressed.append(entry)
+
+    return compressed
+
+def print_singletons(uppers, lowers, uppersname, lowersname):
+    print("  static constexpr singleton {}[] = {{".format(uppersname))
+    for u, c in uppers:
+        print("    {{{:#04x}, {}}},".format(u, c))
+    print("  };")
+    print("  static constexpr unsigned char {}[] = {{".format(lowersname))
+    for i in range(0, len(lowers), 8):
+        print("    {}".format(" ".join("{:#04x},".format(l) for l in lowers[i:i+8])))
+    print("  };")
+
+def print_normal(normal, normalname):
+    print("  static constexpr unsigned char {}[] = {{".format(normalname))
+    for v in normal:
+        print("    {}".format(" ".join("{:#04x},".format(i) for i in v)))
+    print("  };")
+
+def main():
+    file = get_file("https://www.unicode.org/Public/UNIDATA/UnicodeData.txt")
+
+    codepoints = get_codepoints(file)
+
+    CUTOFF=0x10000
+    singletons0 = []
+    singletons1 = []
+    normal0 = []
+    normal1 = []
+    extra = []
+
+    for a, b in to_ranges(get_escaped(codepoints)):
+        if a > 2 * CUTOFF:
+            extra.append((a, b - a))
+        elif a == b - 1:
+            if a & CUTOFF:
+                singletons1.append(a & ~CUTOFF)
+            else:
+                singletons0.append(a)
+        elif a == b - 2:
+            if a & CUTOFF:
+                singletons1.append(a & ~CUTOFF)
+                singletons1.append((a + 1) & ~CUTOFF)
+            else:
+                singletons0.append(a)
+                singletons0.append(a + 1)
+        else:
+            if a >= 2 * CUTOFF:
+                extra.append((a, b - a))
+            elif a & CUTOFF:
+                normal1.append((a & ~CUTOFF, b - a))
+            else:
+                normal0.append((a, b - a))
+
+    singletons0u, singletons0l = compress_singletons(singletons0)
+    singletons1u, singletons1l = compress_singletons(singletons1)
+    normal0 = compress_normal(normal0)
+    normal1 = compress_normal(normal1)
+
+    print("""\
+inline auto is_printable(uint32_t cp) -> bool {\
+""")
+    print_singletons(singletons0u, singletons0l, 'singletons0', 'singletons0_lower')
+    print_singletons(singletons1u, singletons1l, 'singletons1', 'singletons1_lower')
+    print_normal(normal0, 'normal0')
+    print_normal(normal1, 'normal1')
+    print("""\
+  auto lower = static_cast<uint16_t>(cp);
+  if (cp < 0x10000) {
+    return is_printable(lower, singletons0,
+                        sizeof(singletons0) / sizeof(*singletons0),
+                        singletons0_lower, normal0, sizeof(normal0));
+  }
+  if (cp < 0x20000) {
+    return is_printable(lower, singletons1,
+                        sizeof(singletons1) / sizeof(*singletons1),
+                        singletons1_lower, normal1, sizeof(normal1));
+  }\
+""")
+    for a, b in extra:
+        print("  if (0x{:x} <= cp && cp < 0x{:x}) return false;".format(a, a + b))
+    print("""\
+  return cp < 0x{:x};
+}}\
+""".format(NUM_CODEPOINTS))
+
+if __name__ == '__main__':
+    main()

test/CMakeLists.txt

@@ -8,24 +8,21 @@ target_link_libraries(test-main gtest)
 
 include(CheckCXXCompilerFlag)
 
-# Workaround GTest bug https://github.com/google/googletest/issues/705.
-check_cxx_compiler_flag(
-  -fno-delete-null-pointer-checks HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
-if (HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
-  target_compile_options(test-main PUBLIC -fno-delete-null-pointer-checks)
-endif ()
-
-# Use less strict pedantic flags for the tests because GMock doesn't compile
-# cleanly with -pedantic and -std=c++98.
-if (CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
-    #set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -Wno-long-long -Wno-variadic-macros)
-endif ()
-
 function(add_fmt_executable name)
   add_executable(${name} ${ARGN})
   if (MINGW)
     target_link_libraries(${name} -static-libgcc -static-libstdc++)
   endif ()
+  # (Wstringop-overflow) - [meta-bug] bogus/missing -Wstringop-overflow warnings
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443
+  # Bogus -Wstringop-overflow warning
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100395
+  # [10 Regression] spurious -Wstringop-overflow writing to a trailing array plus offset
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95353
+  if (CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND
+      NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0)
+    target_link_libraries(${name} -Wno-stringop-overflow)
+  endif ()
 endfunction()
 
 # Adds a test.
@@ -41,7 +38,7 @@ function(add_fmt_test name)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wno-weak-vtables)
     endif ()
   elseif (ADD_FMT_TEST_MODULE)
-    set(libs test-main test-module)
+    set(libs gtest test-module)
     set_source_files_properties(${name}.cc PROPERTIES OBJECT_DEPENDS test-module)
   else ()
     set(libs test-main fmt)
@@ -74,8 +71,13 @@ if (NOT (MSVC AND BUILD_SHARED_LIBS))
 endif ()
 add_fmt_test(ostream-test)
 add_fmt_test(compile-test)
+add_fmt_test(compile-fp-test HEADER_ONLY)
+if (MSVC)
+  # Without this option, MSVC returns 199711L for the __cplusplus macro.
+  target_compile_options(compile-fp-test PRIVATE /Zc:__cplusplus)
+endif()
 add_fmt_test(printf-test)
-add_fmt_test(ranges-test)
+add_fmt_test(ranges-test ranges-odr-test.cc)
 add_fmt_test(scan-test)
 add_fmt_test(unicode-test HEADER_ONLY)
 if (MSVC)
@@ -97,10 +99,12 @@ if (FMT_CAN_MODULE)
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
   enable_module(test-module)
 
-  add_fmt_test(module-test MODULE)
+  add_fmt_test(module-test MODULE test-main.cc)
   if (MSVC)
-    target_compile_options(test-module PRIVATE /utf-8)
+    target_compile_options(test-module PRIVATE /utf-8 /Zc:__cplusplus
-    target_compile_options(module-test PRIVATE /utf-8)
+                           /Zc:externConstexpr /Zc:inline)
+    target_compile_options(module-test PRIVATE /utf-8 /Zc:__cplusplus
+                           /Zc:externConstexpr /Zc:inline)
   endif ()
 endif ()
 
@@ -133,20 +137,14 @@ endif ()
 
 message(STATUS "FMT_PEDANTIC: ${FMT_PEDANTIC}")
 
-if (FMT_PEDANTIC AND CXX_STANDARD LESS 20)
+if (FMT_PEDANTIC)
-  # MSVC fails to compile GMock when C++17 is enabled.
-  if (FMT_HAS_VARIANT AND NOT MSVC)
-    add_fmt_test(std-format-test)
-    set_property(TARGET std-format-test PROPERTY CXX_STANDARD 17)
-  endif ()
-
   # Test that the library can be compiled with exceptions disabled.
   # -fno-exception is broken in icc: https://github.com/fmtlib/fmt/issues/822.
   if (NOT CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
     check_cxx_compiler_flag(-fno-exceptions HAVE_FNO_EXCEPTIONS_FLAG)
   endif ()
   if (HAVE_FNO_EXCEPTIONS_FLAG)
-    add_library(noexception-test ../src/format.cc)
+    add_library(noexception-test ../src/format.cc noexception-test.cc)
     target_include_directories(
       noexception-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
     target_compile_options(noexception-test PRIVATE -fno-exceptions)
@@ -161,7 +159,11 @@ if (FMT_PEDANTIC AND CXX_STANDARD LESS 20)
     nolocale-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
   target_compile_definitions(
     nolocale-test PRIVATE FMT_STATIC_THOUSANDS_SEPARATOR=1)
+endif ()
 
+# These tests are disabled on Windows because they take too long.
+if (FMT_PEDANTIC AND NOT WIN32)
+  # Test if incorrect API usages produce compilation error.
   add_test(compile-error-test ${CMAKE_CTEST_COMMAND}
     --build-and-test
     "${CMAKE_CURRENT_SOURCE_DIR}/compile-error-test"
@@ -170,14 +172,11 @@ if (FMT_PEDANTIC AND CXX_STANDARD LESS 20)
     --build-makeprogram ${CMAKE_MAKE_PROGRAM}
     --build-options
     "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
     "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
-    "-DCXX_STANDARD_FLAG=${CXX_STANDARD_FLAG}"
+    "-DFMT_DIR=${CMAKE_SOURCE_DIR}"
-    "-DPEDANTIC_COMPILE_FLAGS=${PEDANTIC_COMPILE_FLAGS}"
     "-DSUPPORTS_USER_DEFINED_LITERALS=${SUPPORTS_USER_DEFINED_LITERALS}")
-endif ()
 
-# These tests are disabled on Windows because they take too long.
-if (FMT_PEDANTIC AND NOT WIN32)
   # Test if the targets are found from the build directory.
   add_test(find-package-test ${CMAKE_CTEST_COMMAND}
     -C ${CMAKE_BUILD_TYPE}

test/args-test.cc

@@ -7,10 +7,12 @@
 
 #include "fmt/args.h"
 
+#include <memory>
+
 #include "gtest/gtest.h"
 
 TEST(args_test, basic) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   store.push_back(42);
   store.push_back("abc1");
   store.push_back(1.5f);
@@ -19,7 +21,7 @@ TEST(args_test, basic) {
 
 TEST(args_test, strings_and_refs) {
   // Unfortunately the tests are compiled with old ABI so strings use COW.
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   char str[] = "1234567890";
   store.push_back(str);
   store.push_back(std::cref(str));
@@ -48,7 +50,7 @@ template <> struct formatter<custom_type> {
 FMT_END_NAMESPACE
 
 TEST(args_test, custom_format) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   auto c = custom_type();
   store.push_back(c);
   ++c.i;
@@ -77,7 +79,7 @@ template <> struct formatter<to_stringable> {
 FMT_END_NAMESPACE
 
 TEST(args_test, to_string_and_formatter) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   auto s = to_stringable();
   store.push_back(s);
   store.push_back(std::cref(s));
@@ -85,13 +87,13 @@ TEST(args_test, to_string_and_formatter) {
 }
 
 TEST(args_test, named_int) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   store.push_back(fmt::arg("a1", 42));
   EXPECT_EQ("42", fmt::vformat("{a1}", store));
 }
 
 TEST(args_test, named_strings) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   char str[] = "1234567890";
   store.push_back(fmt::arg("a1", str));
   store.push_back(fmt::arg("a2", std::cref(str)));
@@ -100,7 +102,7 @@ TEST(args_test, named_strings) {
 }
 
 TEST(args_test, named_arg_by_ref) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   char band[] = "Rolling Stones";
   store.push_back(fmt::arg("band", std::cref(band)));
   band[9] = 'c';  // Changing band affects the output.
@@ -108,7 +110,7 @@ TEST(args_test, named_arg_by_ref) {
 }
 
 TEST(args_test, named_custom_format) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   auto c = custom_type();
   store.push_back(fmt::arg("c1", c));
   ++c.i;
@@ -121,7 +123,7 @@ TEST(args_test, named_custom_format) {
 }
 
 TEST(args_test, clear) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   store.push_back(42);
 
   auto result = fmt::vformat("{}", store);
@@ -138,7 +140,7 @@ TEST(args_test, clear) {
 }
 
 TEST(args_test, reserve) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   store.reserve(2, 1);
   store.push_back(1.5f);
   store.push_back(fmt::arg("a1", 42));
@@ -163,7 +165,7 @@ template <> struct formatter<copy_throwable> {
 FMT_END_NAMESPACE
 
 TEST(args_test, throw_on_copy) {
-  auto store = fmt::dynamic_format_arg_store<fmt::format_context>();
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
   store.push_back(std::string("foo"));
   try {
     store.push_back(copy_throwable());
@@ -171,3 +173,14 @@ TEST(args_test, throw_on_copy) {
   }
   EXPECT_EQ(fmt::vformat("{}", store), "foo");
 }
+
+TEST(args_test, move_constructor) {
+  using store_type = fmt::dynamic_format_arg_store<fmt::format_context>;
+  auto store = std::unique_ptr<store_type>(new store_type());
+  store->push_back(42);
+  store->push_back(std::string("foo"));
+  store->push_back(fmt::arg("a1", "foo"));
+  auto moved_store = std::move(*store);
+  store.reset();
+  EXPECT_EQ(fmt::vformat("{} {} {a1}", moved_store), "42 foo foo");
+}

test/chrono-test.cc

@@ -7,6 +7,9 @@
 
 #include "fmt/chrono.h"
 
+#include <ctime>
+#include <vector>
+
 #include "gtest-extra.h"  // EXPECT_THROW_MSG
 #include "util.h"         // get_locale
 
@@ -38,6 +41,36 @@ auto make_second(int s) -> std::tm {
   return time;
 }
 
+std::string system_strftime(const std::string& format, const std::tm* timeptr,
+                            std::locale* locptr = nullptr) {
+  auto loc = locptr ? *locptr : std::locale::classic();
+  auto& facet = std::use_facet<std::time_put<char>>(loc);
+  std::ostringstream os;
+  os.imbue(loc);
+  facet.put(os, os, ' ', timeptr, format.c_str(),
+            format.c_str() + format.size());
+#ifdef _WIN32
+  // Workaround a bug in older versions of Universal CRT.
+  auto str = os.str();
+  if (str == "-0000") str = "+0000";
+  return str;
+#else
+  return os.str();
+#endif
+}
+
+FMT_CONSTEXPR std::tm make_tm(int year, int mon, int mday, int hour, int min,
+                              int sec) {
+  auto tm = std::tm();
+  tm.tm_sec = sec;
+  tm.tm_min = min;
+  tm.tm_hour = hour;
+  tm.tm_mday = mday;
+  tm.tm_mon = mon - 1;
+  tm.tm_year = year - 1900;
+  return tm;
+}
+
 TEST(chrono_test, format_tm) {
   auto tm = std::tm();
   tm.tm_year = 116;
@@ -48,14 +81,132 @@ TEST(chrono_test, format_tm) {
   tm.tm_sec = 33;
   EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
             "The date is 2016-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "2016");
+  EXPECT_EQ(fmt::format("{:%C}", tm), "20");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+  EXPECT_EQ(fmt::format("{:%e}", tm), "25");
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/16");
+  EXPECT_EQ(fmt::format("{:%F}", tm), "2016-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+
+  // Short year
+  tm.tm_year = 999 - 1900;
+  tm.tm_mon = 0;   // for %G
+  tm.tm_mday = 2;  // for %G
+  tm.tm_wday = 3;  // for %G
+  tm.tm_yday = 1;  // for %G
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "0999");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), "0999");
+  EXPECT_EQ(fmt::format("{:%G}", tm), "0999");
+
+  tm.tm_year = 27 - 1900;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "0027");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), "0027");
+
+  // Overflow year
+  tm.tm_year = 2147483647;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "2147485547");
+
+  tm.tm_year = -2147483648;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-2147481748");
+
+  // for week on the year
+  // https://www.cl.cam.ac.uk/~mgk25/iso-time.html
+  std::vector<std::tm> tm_list = {
+      make_tm(1975, 12, 29, 12, 14, 16),  // W01
+      make_tm(1977, 1, 2, 12, 14, 16),    // W53
+      make_tm(1999, 12, 27, 12, 14, 16),  // W52
+      make_tm(1999, 12, 31, 12, 14, 16),  // W52
+      make_tm(2000, 1, 1, 12, 14, 16),    // W52
+      make_tm(2000, 1, 2, 12, 14, 16),    // W52
+      make_tm(2000, 1, 3, 12, 14, 16)     // W1
+  };
+  const std::string iso_week_spec = "%Y-%m-%d: %G %g %V";
+  for (auto ctm : tm_list) {
+    // Calculate tm_yday, tm_wday, etc.
+    std::time_t t = std::mktime(&ctm);
+    tm = *std::localtime(&t);
+
+    auto fmt_spec = fmt::format("{{:{}}}", iso_week_spec);
+    EXPECT_EQ(system_strftime(iso_week_spec, &tm),
+              fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+
+  // Every day from 1970-01-01
+  std::time_t time_now = std::time(nullptr);
+  for (std::time_t t = 6 * 3600; t < time_now; t += 86400) {
+    tm = *std::localtime(&t);
+
+    auto fmt_spec = fmt::format("{{:{}}}", iso_week_spec);
+    EXPECT_EQ(system_strftime(iso_week_spec, &tm),
+              fmt::format(fmt::runtime(fmt_spec), tm));
+  }
 }
 
+// MSVC:
+//  minkernel\crts\ucrt\src\appcrt\time\wcsftime.cpp(971) : Assertion failed:
+//  timeptr->tm_year >= -1900 && timeptr->tm_year <= 8099
+#ifndef _WIN32
+TEST(chrono_test, format_tm_future) {
+  auto tm = std::tm();
+  tm.tm_year = 10445;  // 10000+ years
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is 12345-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "12345");
+  EXPECT_EQ(fmt::format("{:%C}", tm), "123");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/45");
+  EXPECT_EQ(fmt::format("{:%F}", tm), "12345-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+}
+
+TEST(chrono_test, format_tm_past) {
+  auto tm = std::tm();
+  tm.tm_year = -2001;
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is -101-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-101");
+
+  // macOS  %C - "-1"
+  // Linux  %C - "-2"
+  // fmt    %C - "-1"
+  EXPECT_EQ(fmt::format("{:%C}", tm), "-1");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+
+  // macOS  %D - "04/25/01" (%y)
+  // Linux  %D - "04/25/99" (%y)
+  // fmt    %D - "04/25/01" (%y)
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/01");
+
+  EXPECT_EQ(fmt::format("{:%F}", tm), "-101-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+
+  tm.tm_year = -1901;  // -1
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-001");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+
+  tm.tm_year = -1911;  // -11
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-011");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+}
+#endif
+
 TEST(chrono_test, grow_buffer) {
   auto s = std::string("{:");
   for (int i = 0; i < 30; ++i) s += "%c";
   s += "}\n";
   auto t = std::time(nullptr);
-  fmt::format(fmt::runtime(s), *std::localtime(&t));
+  (void)fmt::format(fmt::runtime(s), *std::localtime(&t));
 }
 
 TEST(chrono_test, format_to_empty_container) {
@@ -88,22 +239,45 @@ TEST(chrono_test, gmtime) {
   EXPECT_TRUE(equal(tm, fmt::gmtime(t)));
 }
 
-template <typename TimePoint> auto strftime(TimePoint tp) -> std::string {
+template <typename TimePoint> auto strftime_full(TimePoint tp) -> std::string {
   auto t = std::chrono::system_clock::to_time_t(tp);
   auto tm = *std::localtime(&t);
-  char output[256] = {};
+  return system_strftime("%Y-%m-%d %H:%M:%S", &tm);
-  std::strftime(output, sizeof(output), "%Y-%m-%d %H:%M:%S", &tm);
-  return output;
 }
 
 TEST(chrono_test, time_point) {
   auto t1 = std::chrono::system_clock::now();
-  EXPECT_EQ(strftime(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
+  EXPECT_EQ(strftime_full(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
-  EXPECT_EQ(strftime(t1), fmt::format("{}", t1));
+  EXPECT_EQ(strftime_full(t1), fmt::format("{}", t1));
   using time_point =
       std::chrono::time_point<std::chrono::system_clock, std::chrono::seconds>;
   auto t2 = time_point(std::chrono::seconds(42));
-  EXPECT_EQ(strftime(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
+  EXPECT_EQ(strftime_full(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
+
+  std::vector<std::string> spec_list = {
+      "%%",  "%n",  "%t",  "%Y",  "%EY", "%y",  "%Oy", "%Ey", "%C",
+      "%EC", "%G",  "%g",  "%b",  "%h",  "%B",  "%m",  "%Om", "%U",
+      "%OU", "%W",  "%OW", "%V",  "%OV", "%j",  "%d",  "%Od", "%e",
+      "%Oe", "%a",  "%A",  "%w",  "%Ow", "%u",  "%Ou", "%H",  "%OH",
+      "%I",  "%OI", "%M",  "%OM", "%S",  "%OS", "%x",  "%Ex", "%X",
+      "%EX", "%D",  "%F",  "%R",  "%T",  "%p",  "%z",  "%Z"};
+  spec_list.push_back("%Y-%m-%d %H:%M:%S");
+#ifndef _WIN32
+  // Disabled on Windows because these formats are not consistent among
+  // platforms.
+  spec_list.insert(spec_list.end(), {"%c", "%Ec", "%r"});
+#endif
+
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::localtime(&t);
+
+    auto sys_output = system_strftime(spec, &tm);
+
+    auto fmt_spec = fmt::format("{{:{}}}", spec);
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
+  }
 }
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
@@ -197,41 +371,41 @@ TEST(chrono_test, format_specs) {
 
 TEST(chrono_test, invalid_specs) {
   auto sec = std::chrono::seconds(0);
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%a}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%a}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%A}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%A}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%c}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%c}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%x}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%x}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%Ex}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Ex}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%X}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%X}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%EX}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%EX}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%D}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%D}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%F}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%F}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%Ec}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Ec}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%w}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%w}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%u}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%u}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%b}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%b}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%B}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%B}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%z}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%z}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%Z}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Z}"), sec), fmt::format_error,
                    "no date");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%Eq}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Eq}"), sec), fmt::format_error,
                    "invalid format");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:%Oq}"), sec), fmt::format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Oq}"), sec), fmt::format_error,
                    "invalid format");
 }
 
@@ -279,20 +453,33 @@ TEST(chrono_test, format_default_fp) {
 }
 
 TEST(chrono_test, format_precision) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{:.2}"), std::chrono::seconds(42)),
+  EXPECT_THROW_MSG(
-                   fmt::format_error,
+      (void)fmt::format(runtime("{:.2}"), std::chrono::seconds(42)),
-                   "precision not allowed for this argument type");
+      fmt::format_error, "precision not allowed for this argument type");
+  EXPECT_EQ("1ms", fmt::format("{:.0}", dms(1.234)));
   EXPECT_EQ("1.2ms", fmt::format("{:.1}", dms(1.234)));
   EXPECT_EQ("1.23ms", fmt::format("{:.{}}", dms(1.234), 2));
+
+  EXPECT_EQ("13ms", fmt::format("{:.0}", dms(12.56)));
+  EXPECT_EQ("12.6ms", fmt::format("{:.1}", dms(12.56)));
+  EXPECT_EQ("12.56ms", fmt::format("{:.2}", dms(12.56)));
 }
 
 TEST(chrono_test, format_full_specs) {
+  EXPECT_EQ("1ms   ", fmt::format("{:6.0}", dms(1.234)));
   EXPECT_EQ("1.2ms ", fmt::format("{:6.1}", dms(1.234)));
   EXPECT_EQ("  1.23ms", fmt::format("{:>8.{}}", dms(1.234), 2));
   EXPECT_EQ(" 1.2ms ", fmt::format("{:^{}.{}}", dms(1.234), 7, 1));
   EXPECT_EQ(" 1.23ms ", fmt::format("{0:^{2}.{1}}", dms(1.234), 2, 8));
   EXPECT_EQ("=1.234ms=", fmt::format("{:=^{}.{}}", dms(1.234), 9, 3));
   EXPECT_EQ("*1.2340ms*", fmt::format("{:*^10.4}", dms(1.234)));
+
+  EXPECT_EQ("13ms  ", fmt::format("{:6.0}", dms(12.56)));
+  EXPECT_EQ("    13ms", fmt::format("{:>8.{}}", dms(12.56), 0));
+  EXPECT_EQ(" 13ms ", fmt::format("{:^{}.{}}", dms(12.56), 6, 0));
+  EXPECT_EQ("  13ms  ", fmt::format("{0:^{2}.{1}}", dms(12.56), 0, 8));
+  EXPECT_EQ("==13ms===", fmt::format("{:=^{}.{}}", dms(12.56), 9, 0));
+  EXPECT_EQ("***13ms***", fmt::format("{:*^10.0}", dms(12.56)));
 }
 
 TEST(chrono_test, format_simple_q) {
@@ -306,29 +493,37 @@ TEST(chrono_test, format_simple_q) {
 }
 
 TEST(chrono_test, format_precision_q) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{:.2%Q %q}"), std::chrono::seconds(42)),
+  EXPECT_THROW_MSG(
-                   fmt::format_error,
+      (void)fmt::format(runtime("{:.2%Q %q}"), std::chrono::seconds(42)),
-                   "precision not allowed for this argument type");
+      fmt::format_error, "precision not allowed for this argument type");
   EXPECT_EQ("1.2 ms", fmt::format("{:.1%Q %q}", dms(1.234)));
   EXPECT_EQ("1.23 ms", fmt::format("{:.{}%Q %q}", dms(1.234), 2));
 }
 
 TEST(chrono_test, format_full_specs_q) {
+  EXPECT_EQ("1 ms   ", fmt::format("{:7.0%Q %q}", dms(1.234)));
   EXPECT_EQ("1.2 ms ", fmt::format("{:7.1%Q %q}", dms(1.234)));
   EXPECT_EQ(" 1.23 ms", fmt::format("{:>8.{}%Q %q}", dms(1.234), 2));
   EXPECT_EQ(" 1.2 ms ", fmt::format("{:^{}.{}%Q %q}", dms(1.234), 8, 1));
   EXPECT_EQ(" 1.23 ms ", fmt::format("{0:^{2}.{1}%Q %q}", dms(1.234), 2, 9));
   EXPECT_EQ("=1.234 ms=", fmt::format("{:=^{}.{}%Q %q}", dms(1.234), 10, 3));
   EXPECT_EQ("*1.2340 ms*", fmt::format("{:*^11.4%Q %q}", dms(1.234)));
+
+  EXPECT_EQ("13 ms  ", fmt::format("{:7.0%Q %q}", dms(12.56)));
+  EXPECT_EQ("   13 ms", fmt::format("{:>8.{}%Q %q}", dms(12.56), 0));
+  EXPECT_EQ(" 13 ms  ", fmt::format("{:^{}.{}%Q %q}", dms(12.56), 8, 0));
+  EXPECT_EQ("  13 ms  ", fmt::format("{0:^{2}.{1}%Q %q}", dms(12.56), 0, 9));
+  EXPECT_EQ("==13 ms==", fmt::format("{:=^{}.{}%Q %q}", dms(12.56), 9, 0));
+  EXPECT_EQ("***13 ms***", fmt::format("{:*^11.0%Q %q}", dms(12.56)));
 }
 
 TEST(chrono_test, invalid_width_id) {
-  EXPECT_THROW(fmt::format(runtime("{:{o}"), std::chrono::seconds(0)),
+  EXPECT_THROW((void)fmt::format(runtime("{:{o}"), std::chrono::seconds(0)),
                fmt::format_error);
 }
 
 TEST(chrono_test, invalid_colons) {
-  EXPECT_THROW(fmt::format(runtime("{0}=:{0::"), std::chrono::seconds(0)),
+  EXPECT_THROW((void)fmt::format(runtime("{0}=:{0::"), std::chrono::seconds(0)),
                fmt::format_error);
 }
 
@@ -348,15 +543,12 @@ TEST(chrono_test, negative_durations) {
 }
 
 TEST(chrono_test, special_durations) {
-  EXPECT_EQ(
+  auto value = fmt::format("{:%S}", std::chrono::duration<double>(1e20));
-      "40.",
+  EXPECT_EQ(value, "40");
-      fmt::format("{:%S}", std::chrono::duration<double>(1e20)).substr(0, 3));
   auto nan = std::numeric_limits<double>::quiet_NaN();
   EXPECT_EQ(
       "nan nan nan nan nan:nan nan",
       fmt::format("{:%I %H %M %S %R %r}", std::chrono::duration<double>(nan)));
-  fmt::format("{:%S}",
-              std::chrono::duration<float, std::atto>(1.79400457e+31f));
   EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::exa>(1)),
             "1Es");
   EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::atto>(1)),
@@ -375,11 +567,59 @@ TEST(chrono_test, weekday) {
   auto loc = get_locale("ru_RU.UTF-8");
   std::locale::global(loc);
   auto mon = fmt::weekday(1);
+
+  auto tm = std::tm();
+  tm.tm_wday = static_cast<int>(mon.c_encoding());
+
   EXPECT_EQ(fmt::format("{}", mon), "Mon");
+  EXPECT_EQ(fmt::format("{:%a}", tm), "Mon");
+
   if (loc != std::locale::classic()) {
     EXPECT_THAT((std::vector<std::string>{"пн", "Пн", "пнд", "Пнд"}),
                 Contains(fmt::format(loc, "{:L}", mon)));
+    EXPECT_THAT((std::vector<std::string>{"пн", "Пн", "пнд", "Пнд"}),
+                Contains(fmt::format(loc, "{:%a}", tm)));
   }
 }
 
+TEST(chrono_test, cpp20_duration_subsecond_support) {
+  using attoseconds = std::chrono::duration<long long, std::atto>;
+  // Check that 18 digits of subsecond precision are supported.
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{999999999999999999}),
+            "00.999999999999999999");
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{673231113420148734}),
+            "00.673231113420148734");
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{-673231113420148734}),
+            "-00.673231113420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{13420148734}),
+            "13.420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{-13420148734}),
+            "-13.420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::milliseconds{1234}), "01.234");
+  {
+    // Check that {:%H:%M:%S} is equivalent to {:%T}.
+    auto dur = std::chrono::milliseconds{3601234};
+    auto formatted_dur = fmt::format("{:%T}", dur);
+    EXPECT_EQ(formatted_dur, "01:00:01.234");
+    EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
+  }
+  using nanoseconds_dbl = std::chrono::duration<double, std::nano>;
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{-123456789}), "-00.123456789");
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{9123456789}), "09.123456789");
+  // Verify that only the seconds part is extracted and printed.
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123456789}), "39.123456789");
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123000000}), "39.123000000");
+  {
+    // Now the hour is printed, and we also test if negative doubles work.
+    auto dur = nanoseconds_dbl{-99123456789};
+    auto formatted_dur = fmt::format("{:%T}", dur);
+    EXPECT_EQ(formatted_dur, "-00:01:39.123456789");
+    EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
+  }
+  // Check that durations with precision greater than std::chrono::seconds have
+  // fixed precision, and print zeros even if there is no fractional part.
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::microseconds{7000000}),
+            "07.000000");
+}
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR

test/color-test.cc

@@ -20,10 +20,16 @@ TEST(color_test, format) {
       fmt::format(fg(fmt::color::blue) | bg(fmt::color::red), "two color"),
       "\x1b[38;2;000;000;255m\x1b[48;2;255;000;000mtwo color\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::bold, "bold"), "\x1b[1mbold\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::faint, "faint"), "\x1b[2mfaint\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::italic, "italic"),
             "\x1b[3mitalic\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::underline, "underline"),
             "\x1b[4munderline\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::blink, "blink"), "\x1b[5mblink\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::reverse, "reverse"),
+            "\x1b[7mreverse\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::conceal, "conceal"),
+            "\x1b[8mconceal\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::strikethrough, "strikethrough"),
             "\x1b[9mstrikethrough\x1b[0m");
   EXPECT_EQ(

test/compile-error-test/CMakeLists.txt

@@ -1,71 +1,158 @@
 # Test if compile errors are produced where necessary.
 
 cmake_minimum_required(VERSION 3.1...3.18)
+project(compile-error-test CXX)
 
-include(CheckCXXSourceCompiles)
+set(fmt_headers "
-include(CheckCXXCompilerFlag)
+  #include <fmt/format.h>
+  #include <fmt/xchar.h>
+")
 
-set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR}/../../include)
+set(error_test_names "")
-set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG} ${PEDANTIC_COMPILE_FLAGS})
+set(non_error_test_content "")
 
-function (generate_source result fragment)
+# For error tests (we expect them to produce compilation error):
-  set(${result} "
+#  * adds a name of test into `error_test_names` list
-  #define FMT_HEADER_ONLY 1
+#  * generates a single source file (with the same name) for each test
-  #include \"fmt/format.h\"
+# For non-error tests (we expect them to compile successfully):
-  int main() {
+#  * adds a code segment as separate function to `non_error_test_content`
-    ${fragment}
+function (expect_compile name code_fragment)
-  }
+  cmake_parse_arguments(EXPECT_COMPILE "ERROR" "" "" ${ARGN})
-  " PARENT_SCOPE)
+  string(MAKE_C_IDENTIFIER "${name}" test_name)
+
+  if (EXPECT_COMPILE_ERROR)
+    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/${test_name}.cc" "
+      ${fmt_headers}
+      void ${test_name}() {
+        ${code_fragment}
+      }
+    ")
+    set(error_test_names_copy "${error_test_names}")
+    list(APPEND error_test_names_copy "${test_name}")
+    set(error_test_names "${error_test_names_copy}" PARENT_SCOPE)
+  else()
+    set(non_error_test_content "
+      ${non_error_test_content}
+      void ${test_name}() {
+        ${code_fragment}
+      }" PARENT_SCOPE)
+  endif()
 endfunction ()
 
-function (expect_compile code)
+# Generates a source file for non-error test with `non_error_test_content` and
-  generate_source(source "${code}")
+# CMake project file with all error and single non-error test targets.
-  check_cxx_source_compiles("${source}" compiles)
+function (run_tests)
-  if (NOT compiles)
+  set(cmake_targets "")
-    set(error_msg "Compile error for: ${code}")
+  foreach(test_name IN LISTS error_test_names)
-  endif ()
+    set(cmake_targets "
-  # Unset the CMake cache variable compiles. Otherwise the compile test will
+      ${cmake_targets}
-  # just use cached information next time it runs.
+      add_library(test-${test_name} ${test_name}.cc)
-  unset(compiles CACHE)
+      target_link_libraries(test-${test_name} PRIVATE fmt::fmt)
-  if (error_msg)
+    ")
-    message(FATAL_ERROR ${error_msg})
+  endforeach()
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/non_error_test.cc" "
+    ${fmt_headers}
+    ${non_error_test_content}
+  ")
+  set(cmake_targets "
+    ${cmake_targets}
+    add_library(non-error-test non_error_test.cc)
+    target_link_libraries(non-error-test PRIVATE fmt::fmt)
+  ")
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/CMakeLists.txt" "
+    cmake_minimum_required(VERSION 3.1...3.18)
+    project(tests CXX)
+    add_subdirectory(${FMT_DIR} fmt)
+    ${cmake_targets}
+  ")
+
+  set(build_directory "${CMAKE_CURRENT_BINARY_DIR}/test/build")
+  file(MAKE_DIRECTORY "${build_directory}")
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}"
+      "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+      "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+      "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+      "-DCMAKE_GENERATOR=${CMAKE_GENERATOR}"
+      "-DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}"
+      "-DFMT_DIR=${FMT_DIR}"
+      "${CMAKE_CURRENT_BINARY_DIR}/test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(FATAL_ERROR "Unable to configure:\n${output_var}")
+  endif()
+
+  foreach(test_name IN LISTS error_test_names)
+    execute_process(
+      COMMAND
+        "${CMAKE_COMMAND}" --build "${build_directory}" --target "test-${test_name}"
+      WORKING_DIRECTORY "${build_directory}"
+      RESULT_VARIABLE result_var
+      OUTPUT_VARIABLE output_var
+      ERROR_QUIET)
+    if (result_var EQUAL 0)
+      message(SEND_ERROR "No compile error for \"${test_name}\":\n${output_var}")
+    endif ()
+  endforeach()
+
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}" --build "${build_directory}" --target "non-error-test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(SEND_ERROR "Compile error for combined non-error test:\n${output_var}")
   endif ()
 endfunction ()
 
-function (expect_compile_error code)
-  generate_source(source "${code}")
-  check_cxx_source_compiles("${source}" compiles)
-  if (compiles)
-    set(error_msg "No compile error for: ${code}")
-  endif ()
-  # Unset the CMake cache variable compiles. Otherwise the compile test will
-  # just use cached information next time it runs.
-  unset(compiles CACHE)
-  if (error_msg)
-    message(FATAL_ERROR ${error_msg})
-  endif ()
-endfunction ()
 
 # check if the source file skeleton compiles
-expect_compile("")
+expect_compile(check "")
+expect_compile(check-error "compilation_error" ERROR)
 
 # Formatting a wide character with a narrow format string is forbidden.
-expect_compile_error("fmt::format(\"{}\", L'a');")
+expect_compile(wide-character-narrow-format-string "fmt::format(L\"{}\", L'a');")
+expect_compile(wide-character-narrow-format-string-error "fmt::format(\"{}\", L'a');" ERROR)
 
 # Formatting a wide string with a narrow format string is forbidden.
-expect_compile_error("fmt::format(\"{}\", L\"foo\");")
+expect_compile(wide-string-narrow-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(wide-string-narrow-format-string-error "fmt::format(\"{}\", L\"foo\");" ERROR)
 
 # Formatting a narrow string with a wide format string is forbidden because
 # mixing UTF-8 with UTF-16/32 can result in an invalid output.
-expect_compile_error("fmt::format(L\"{}\", \"foo\");")
+expect_compile(narrow-string-wide-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(narrow-string-wide-format-string-error "fmt::format(L\"{}\", \"foo\");" ERROR)
 
-# Formatting a wide string with a narrow format string is forbidden.
+expect_compile(cast-to-string "
-expect_compile_error("
+  struct S {
+    operator std::string() const { return std::string(); }
+  };
+  fmt::format(\"{}\", std::string(S()));
+")
+expect_compile(cast-to-string-error "
   struct S {
     operator std::string() const { return std::string(); }
   };
   fmt::format(\"{}\", S());
+" ERROR)
+
+# Formatting a function
+expect_compile(format-function "
+  void (*f)();
+  fmt::format(\"{}\", fmt::ptr(f));
 ")
+expect_compile(format-function-error "
+  void (*f)();
+  fmt::format(\"{}\", f);
+" ERROR)
 
 # Make sure that compiler features detected in the header
 # match the features detected in CMake.
@@ -74,6 +161,43 @@ if (SUPPORTS_USER_DEFINED_LITERALS)
 else ()
   set(supports_udl 0)
 endif ()
-expect_compile("#if FMT_USE_USER_DEFINED_LITERALS != ${supports_udl}
+expect_compile(udl-check "
-                # error
+  #if FMT_USE_USER_DEFINED_LITERALS != ${supports_udl}
-                #endif")
+  # error
+  #endif
+")
+
+if (CMAKE_CXX_STANDARD GREATER_EQUAL 20)
+  # Compile-time argument type check
+  expect_compile(format-string-number-spec "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", 42);
+    #endif
+  ")
+  expect_compile(format-string-number-spec-error "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", \"I am not a number\");
+    #else
+      #error
+    #endif
+  " ERROR)
+
+  # Compile-time argument name check
+  expect_compile(format-string-name "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"foo\"_a=42);
+    #endif
+  ")
+  expect_compile(format-string-name-error "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"bar\"_a=42);
+    #else
+      #error
+    #endif
+  " ERROR)
+endif ()
+
+# Run all tests
+run_tests()

test/compile-fp-test.cc

@@ -0,0 +1,62 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/compile.h"
+#include "gmock/gmock.h"
+
+#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806 && \
+    defined(__cpp_constexpr) && __cpp_constexpr >= 201907 &&       \
+    defined(__cpp_constexpr_dynamic_alloc) &&                      \
+    __cpp_constexpr_dynamic_alloc >= 201907 && __cplusplus >= 202002L
+template <size_t max_string_length, typename Char = char> struct test_string {
+  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+    return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
+  }
+  Char buffer[max_string_length]{};
+};
+
+template <size_t max_string_length, typename Char = char, typename... Args>
+consteval auto test_format(auto format, const Args&... args) {
+  test_string<max_string_length, Char> string{};
+  fmt::format_to(string.buffer, format, args...);
+  return string;
+}
+
+TEST(compile_time_formatting_test, floating_point) {
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{}"), 0.0f));
+  EXPECT_EQ("392.500000", test_format<11>(FMT_COMPILE("{0:f}"), 392.5f));
+
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:}"), 0.0));
+  EXPECT_EQ("0.000000", test_format<9>(FMT_COMPILE("{:f}"), 0.0));
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:g}"), 0.0));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:g}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:G}"), 392.65));
+  EXPECT_EQ("4.9014e+06", test_format<11>(FMT_COMPILE("{:g}"), 4.9014e6));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:f}"), -392.65));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:F}"), -392.65));
+
+  EXPECT_EQ("3.926500e+02", test_format<13>(FMT_COMPILE("{0:e}"), 392.65));
+  EXPECT_EQ("3.926500E+02", test_format<13>(FMT_COMPILE("{0:E}"), 392.65));
+  EXPECT_EQ("+0000392.6", test_format<11>(FMT_COMPILE("{0:+010.4g}"), 392.65));
+  EXPECT_EQ("9223372036854775808.000000",
+            test_format<27>(FMT_COMPILE("{:f}"), 9223372036854775807.0));
+
+  constexpr double nan = std::numeric_limits<double>::quiet_NaN();
+  EXPECT_EQ("nan", test_format<4>(FMT_COMPILE("{}"), nan));
+  EXPECT_EQ("+nan", test_format<5>(FMT_COMPILE("{:+}"), nan));
+  if (std::signbit(-nan))
+    EXPECT_EQ("-nan", test_format<5>(FMT_COMPILE("{}"), -nan));
+  else
+    fmt::print("Warning: compiler doesn't handle negative NaN correctly");
+
+  constexpr double inf = std::numeric_limits<double>::infinity();
+  EXPECT_EQ("inf", test_format<4>(FMT_COMPILE("{}"), inf));
+  EXPECT_EQ("+inf", test_format<5>(FMT_COMPILE("{:+}"), inf));
+  EXPECT_EQ("-inf", test_format<5>(FMT_COMPILE("{}"), -inf));
+}
+#endif

test/compile-test.cc

@@ -59,7 +59,24 @@ TEST(compile_test, compile_fallback) {
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
 }
 
-#ifdef __cpp_if_constexpr
+struct type_with_get {
+  template <int> friend void get(type_with_get);
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<type_with_get> : formatter<int> {
+  template <typename FormatContext>
+  auto format(type_with_get, FormatContext& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(42, ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, compile_type_with_get) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), type_with_get()));
+}
+
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 struct test_formattable {};
 
 FMT_BEGIN_NAMESPACE

test/core-test.cc

@@ -151,7 +151,9 @@ TEST(buffer_test, indestructible) {
 template <typename T> struct mock_buffer final : buffer<T> {
   MOCK_METHOD1(do_grow, size_t(size_t capacity));
 
-  void grow(size_t capacity) { this->set(this->data(), do_grow(capacity)); }
+  void grow(size_t capacity) override {
+    this->set(this->data(), do_grow(capacity));
+  }
 
   mock_buffer(T* data = nullptr, size_t buf_capacity = 0) {
     this->set(data, buf_capacity);
@@ -406,15 +408,7 @@ TYPED_TEST(numeric_arg_test, make_and_visit) {
   CHECK_ARG_SIMPLE(std::numeric_limits<TypeParam>::max());
 }
 
-namespace fmt {
+TEST(arg_test, char_arg) { CHECK_ARG(char, 'a', 'a'); }
-template <> struct is_char<wchar_t> : std::true_type {};
-}  // namespace fmt
-
-TEST(arg_test, char_arg) {
-  CHECK_ARG(char, 'a', 'a');
-  CHECK_ARG(wchar_t, L'a', 'a');
-  CHECK_ARG(wchar_t, L'a', L'a');
-}
 
 TEST(arg_test, string_arg) {
   char str_data[] = "test";
@@ -452,7 +446,7 @@ struct check_custom {
     struct test_buffer final : fmt::detail::buffer<char> {
       char data[10];
       test_buffer() : fmt::detail::buffer<char>(data, 0, 10) {}
-      void grow(size_t) {}
+      void grow(size_t) override {}
     } buffer;
     auto parse_ctx = fmt::format_parse_context("");
     auto ctx = fmt::format_context(fmt::detail::buffer_appender<char>(buffer),
@@ -530,7 +524,7 @@ struct test_format_specs_handler {
   fmt::detail::arg_ref<char> width_ref;
   int precision = 0;
   fmt::detail::arg_ref<char> precision_ref;
-  char type = 0;
+  fmt::presentation_type type = fmt::presentation_type::none;
 
   // Workaround for MSVC2017 bug that results in "expression did not evaluate
   // to a constant" with compiler-generated copy ctor.
@@ -556,14 +550,14 @@ struct test_format_specs_handler {
   constexpr void on_dynamic_precision(string_view) {}
 
   constexpr void end_precision() {}
-  constexpr void on_type(char t) { type = t; }
+  constexpr void on_type(fmt::presentation_type t) { type = t; }
   constexpr void on_error(const char*) { res = error; }
 };
 
 template <size_t N>
 constexpr test_format_specs_handler parse_test_specs(const char (&s)[N]) {
   auto h = test_format_specs_handler();
-  fmt::detail::parse_format_specs(s, s + N, h);
+  fmt::detail::parse_format_specs(s, s + N - 1, h);
   return h;
 }
 
@@ -581,7 +575,7 @@ TEST(core_test, constexpr_parse_format_specs) {
   static_assert(parse_test_specs("{42}").width_ref.val.index == 42, "");
   static_assert(parse_test_specs(".42").precision == 42, "");
   static_assert(parse_test_specs(".{42}").precision_ref.val.index == 42, "");
-  static_assert(parse_test_specs("d").type == 'd', "");
+  static_assert(parse_test_specs("d").type == fmt::presentation_type::dec, "");
   static_assert(parse_test_specs("{<").res == handler::error, "");
 }
 
@@ -603,7 +597,7 @@ constexpr fmt::detail::dynamic_format_specs<char> parse_dynamic_specs(
   auto specs = fmt::detail::dynamic_format_specs<char>();
   auto ctx = test_parse_context();
   auto h = fmt::detail::dynamic_specs_handler<test_parse_context>(specs, ctx);
-  parse_format_specs(s, s + N, h);
+  parse_format_specs(s, s + N - 1, h);
   return specs;
 }
 
@@ -621,14 +615,15 @@ TEST(format_test, constexpr_dynamic_specs_handler) {
   static_assert(parse_dynamic_specs(".42").precision == 42, "");
   static_assert(parse_dynamic_specs(".{}").precision_ref.val.index == 11, "");
   static_assert(parse_dynamic_specs(".{42}").precision_ref.val.index == 42, "");
-  static_assert(parse_dynamic_specs("d").type == 'd', "");
+  static_assert(parse_dynamic_specs("d").type == fmt::presentation_type::dec,
+                "");
 }
 
 template <size_t N>
 constexpr test_format_specs_handler check_specs(const char (&s)[N]) {
   fmt::detail::specs_checker<test_format_specs_handler> checker(
       test_format_specs_handler(), fmt::detail::type::double_type);
-  parse_format_specs(s, s + N, checker);
+  parse_format_specs(s, s + N - 1, checker);
   return checker;
 }
 
@@ -645,7 +640,7 @@ TEST(format_test, constexpr_specs_checker) {
   static_assert(check_specs("{42}").width_ref.val.index == 42, "");
   static_assert(check_specs(".42").precision == 42, "");
   static_assert(check_specs(".{42}").precision_ref.val.index == 42, "");
-  static_assert(check_specs("d").type == 'd', "");
+  static_assert(check_specs("d").type == fmt::presentation_type::dec, "");
   static_assert(check_specs("{<").res == handler::error, "");
 }
 
@@ -709,10 +704,80 @@ TEST(core_test, has_formatter) {
                 "");
 }
 
+struct const_formattable {};
+struct nonconst_formattable {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<const_formattable> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(const const_formattable&, format_context& ctx)
+      -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+
+template <> struct formatter<nonconst_formattable> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(nonconst_formattable&, format_context& ctx)
+      -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+FMT_END_NAMESPACE
+
+struct convertible_to_pointer {
+  operator const int*() const { return nullptr; }
+};
+
+enum class test_scoped_enum {};
+
 TEST(core_test, is_formattable) {
+#if 0
+  // This should be enabled once corresponding map overloads are gone.
+  static_assert(fmt::is_formattable<signed char*>::value, "");
+  static_assert(fmt::is_formattable<unsigned char*>::value, "");
+  static_assert(fmt::is_formattable<const signed char*>::value, "");
+  static_assert(fmt::is_formattable<const unsigned char*>::value, "");
+#endif
+  static_assert(!fmt::is_formattable<wchar_t>::value, "");
+#ifdef __cpp_char8_t
+  static_assert(!fmt::is_formattable<char8_t>::value, "");
+#endif
+  static_assert(!fmt::is_formattable<char16_t>::value, "");
+  static_assert(!fmt::is_formattable<char32_t>::value, "");
+  static_assert(!fmt::is_formattable<const wchar_t*>::value, "");
+  static_assert(!fmt::is_formattable<const wchar_t[3]>::value, "");
+  static_assert(!fmt::is_formattable<fmt::basic_string_view<wchar_t>>::value,
+                "");
   static_assert(fmt::is_formattable<enabled_formatter>::value, "");
   static_assert(!fmt::is_formattable<disabled_formatter>::value, "");
   static_assert(fmt::is_formattable<disabled_formatter_convertible>::value, "");
+
+  static_assert(fmt::is_formattable<const_formattable&>::value, "");
+  static_assert(fmt::is_formattable<const const_formattable&>::value, "");
+
+  static_assert(fmt::is_formattable<nonconst_formattable&>::value, "");
+#if !FMT_MSC_VER || FMT_MSC_VER >= 1910
+  static_assert(!fmt::is_formattable<const nonconst_formattable&>::value, "");
+#endif
+
+  static_assert(!fmt::is_formattable<convertible_to_pointer>::value, "");
+
+  static_assert(!fmt::is_formattable<void (*)()>::value, "");
+
+  struct s;
+
+  static_assert(!fmt::is_formattable<int(s::*)>::value, "");
+  static_assert(!fmt::is_formattable<int (s::*)()>::value, "");
+  static_assert(!fmt::is_formattable<test_scoped_enum>::value, "");
 }
 
 TEST(core_test, format) { EXPECT_EQ(fmt::format("{}", 42), "42"); }
@@ -838,10 +903,21 @@ TEST(core_test, adl) {
   if (fmt::detail::const_check(true)) return;
   auto s = adl_test::string();
   char buf[10];
-  fmt::format("{}", s);
+  (void)fmt::format("{}", s);
   fmt::format_to(buf, "{}", s);
   fmt::format_to_n(buf, 10, "{}", s);
-  fmt::formatted_size("{}", s);
+  (void)fmt::formatted_size("{}", s);
   fmt::print("{}", s);
   fmt::print(stdout, "{}", s);
 }
+
+TEST(core_test, has_const_formatter) {
+  EXPECT_TRUE((fmt::detail::has_const_formatter<const_formattable,
+                                                fmt::format_context>()));
+  EXPECT_FALSE((fmt::detail::has_const_formatter<nonconst_formattable,
+                                                 fmt::format_context>()));
+}
+
+TEST(core_test, format_nonconst) {
+  EXPECT_EQ(fmt::format("{}", nonconst_formattable()), "test");
+}

test/enforce-checks-test.cc

@@ -17,12 +17,12 @@
 
 // Exercise the API to verify that everything we expect to can compile.
 void test_format_api() {
-  fmt::format(FMT_STRING("{}"), 42);
+  (void)fmt::format(FMT_STRING("{}"), 42);
-  fmt::format(FMT_STRING(L"{}"), 42);
+  (void)fmt::format(FMT_STRING(L"{}"), 42);
-  fmt::format(FMT_STRING("noop"));
+  (void)fmt::format(FMT_STRING("noop"));
 
-  fmt::to_string(42);
+  (void)fmt::to_string(42);
-  fmt::to_wstring(42);
+  (void)fmt::to_wstring(42);
 
   std::vector<char> out;
   fmt::format_to(std::back_inserter(out), FMT_STRING("{}"), 42);
@@ -35,13 +35,14 @@ void test_format_api() {
 }
 
 void test_chrono() {
-  fmt::format(FMT_STRING("{}"), std::chrono::seconds(42));
+  (void)fmt::format(FMT_STRING("{}"), std::chrono::seconds(42));
-  fmt::format(FMT_STRING(L"{}"), std::chrono::seconds(42));
+  (void)fmt::format(FMT_STRING(L"{}"), std::chrono::seconds(42));
 }
 
 void test_text_style() {
   fmt::print(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"), "rgb(255,20,30)");
-  fmt::format(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"), "rgb(255,20,30)");
+  (void)fmt::format(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"),
+                    "rgb(255,20,30)");
 
   fmt::text_style ts = fg(fmt::rgb(255, 20, 30));
   std::string out;
@@ -51,7 +52,7 @@ void test_text_style() {
 
 void test_range() {
   std::vector<char> hello = {'h', 'e', 'l', 'l', 'o'};
-  fmt::format(FMT_STRING("{}"), hello);
+  (void)fmt::format(FMT_STRING("{}"), hello);
 }
 
 int main() {

test/find-package-test/main.cc

@@ -1,6 +1,5 @@
 #include "fmt/format.h"
 
 int main(int argc, char** argv) {
-  for(int i = 0; i < argc; ++i)
+  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
-    fmt::print("{}: {}\n", i, argv[i]);
 }

test/format

@@ -1,856 +0,0 @@
-// Formatting library for C++ - the standard API implementation
-//
-// Copyright (c) 2012 - present, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_FORMAT_
-#define FMT_FORMAT_
-
-#include <algorithm>
-#include <cassert>
-#include <variant>
-#include "fmt/format.h"
-
-// This implementation verifies the correctness of the standard API proposed in
-// P0645 Text Formatting and is optimized for copy-pasting from the paper, not
-// for efficiency or readability. An efficient implementation should not use
-// std::variant and should store packed argument type tags separately from
-// values in basic_format_args for small number of arguments.
-
-namespace std {
-template<class T>
-constexpr bool Integral = is_integral_v<T>;
-
-template <class O>
-  using iter_difference_t = ptrdiff_t;
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.syn
-namespace std {
-  // [format.error], class format_error
-  class format_error;
-
-  // [format.formatter], formatter
-  template<class charT> class basic_format_parse_context;
-  using format_parse_context = basic_format_parse_context<char>;
-  using wformat_parse_context = basic_format_parse_context<wchar_t>;
-  
-  template<class Out, class charT> class basic_format_context;
-  using format_context = basic_format_context<
-    /* unspecified */ fmt::detail::buffer_appender<char>, char>;
-  using wformat_context = basic_format_context<
-    /* unspecified */ fmt::detail::buffer_appender<wchar_t>, wchar_t>;
-
-  template<class T, class charT = char> struct formatter {
-    formatter() = delete;
-  };
-  
-  // [format.arguments], arguments
-  template<class Context> class basic_format_arg;
-
-  template<class Visitor, class Context>
-    /* see below */ auto visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
-
-  template<class Context, class... Args> struct format_arg_store; // exposition only
-
-  template<class Context> class basic_format_args;
-  using format_args = basic_format_args<format_context>;
-  using wformat_args = basic_format_args<wformat_context>;
-
-  template<class Out, class charT>
-    using format_args_t = basic_format_args<basic_format_context<Out, charT>>;
-
-  template<class Context = format_context, class... Args>
-    format_arg_store<Context, Args...>
-      make_format_args(const Args&... args);
-  template<class... Args>
-    format_arg_store<wformat_context, Args...>
-      make_wformat_args(const Args&... args);
-
-  // [format.functions], formatting functions
-  template<class... Args>
-    string format(string_view fmt, const Args&... args);
-  template<class... Args>
-    wstring format(wstring_view fmt, const Args&... args);
-
-  string vformat(string_view fmt, format_args args);
-  wstring vformat(wstring_view fmt, wformat_args args);
-
-  template<class Out, class... Args>
-    Out format_to(Out out, string_view fmt, const Args&... args);
-  template<class Out, class... Args>
-    Out format_to(Out out, wstring_view fmt, const Args&... args);
-
-  template<class Out>
-    Out vformat_to(Out out, string_view fmt, format_args_t<fmt::type_identity_t<Out>, char> args);
-  template<class Out>
-    Out vformat_to(Out out, wstring_view fmt, format_args_t<fmt::type_identity_t<Out>, wchar_t> args);
-
-  template<class Out>
-    struct format_to_n_result {
-      Out out;
-      iter_difference_t<Out> size;
-    };
-  
-  template<class Out, class... Args>
-    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                        string_view fmt, const Args&... args);
-  template<class Out, class... Args>
-    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                        wstring_view fmt, const Args&... args);
-
-  template<class... Args>
-    size_t formatted_size(string_view fmt, const Args&... args);
-  template<class... Args>
-    size_t formatted_size(wstring_view fmt, const Args&... args);
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.error
-namespace std {
-  class format_error : public runtime_error {
-  public:
-    explicit format_error(const string& what_arg) : runtime_error(what_arg) {}
-    explicit format_error(const char* what_arg) : runtime_error(what_arg) {}
-  };
-}
-
-namespace std {
-namespace detail {
-struct error_handler {
-  // This function is intentionally not constexpr to give a compile-time error.
-  void on_error(const char* message) {
-    throw std::format_error(message);
-  }
-};
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.parse_context
-namespace std {
-  template<class charT>
-  class basic_format_parse_context {
-  public:
-    using char_type = charT;
-    using const_iterator = typename basic_string_view<charT>::const_iterator;
-    using iterator = const_iterator;
-
-  private:
-    iterator begin_;                              // exposition only
-    iterator end_;                                // exposition only
-    enum indexing { unknown, manual, automatic }; // exposition only
-    indexing indexing_;                           // exposition only
-    size_t next_arg_id_;                          // exposition only
-    size_t num_args_;                             // exposition only
-
-  public:
-    explicit constexpr basic_format_parse_context(basic_string_view<charT> fmt,
-                                                  size_t num_args = 0) noexcept;
-    basic_format_parse_context(const basic_format_parse_context&) = delete;
-    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
-
-    constexpr const_iterator begin() const noexcept;
-    constexpr const_iterator end() const noexcept;
-    constexpr void advance_to(const_iterator it);
-
-    constexpr size_t next_arg_id();
-    constexpr void check_arg_id(size_t id);
-
-    // Implementation detail:
-    constexpr void check_arg_id(fmt::string_view) {}
-    detail::error_handler error_handler() const { return {}; }
-    void on_error(const char* msg) { error_handler().on_error(msg); }
-  };
-}
-
-namespace std {
-template<class charT>
-/* explicit */ constexpr basic_format_parse_context<charT>::
-                   basic_format_parse_context(basic_string_view<charT> fmt,
-                                              size_t num_args) noexcept
-: begin_(fmt.begin()), end_(fmt.end()), indexing_(unknown), next_arg_id_(0), num_args_(num_args) {}
-
-template<class charT>
-constexpr typename basic_format_parse_context<charT>::const_iterator basic_format_parse_context<charT>::begin() const noexcept { return begin_; }
-
-template<class charT>
-constexpr typename basic_format_parse_context<charT>::const_iterator basic_format_parse_context<charT>::end() const noexcept { return end_; }
-
-template<class charT>
-constexpr void basic_format_parse_context<charT>::advance_to(typename basic_format_parse_context<charT>::iterator it) { begin_ = it; }
-
-template<class charT>
-constexpr size_t basic_format_parse_context<charT>::next_arg_id() {
-  if (indexing_ == manual)
-    throw format_error("manual to automatic indexing");
-  if (indexing_ == unknown)
-    indexing_ = automatic;
-  return next_arg_id_++;
-}
-
-template<class charT>
-constexpr void basic_format_parse_context<charT>::check_arg_id(size_t id) {
-  // clang doesn't support __builtin_is_constant_evaluated yet
-  //if (!(!__builtin_is_constant_evaluated() || id < num_args_))
-  //  throw format_error(invalid index is out of range");
-  if (indexing_ == automatic)
-    throw format_error("automatic to manual indexing");
-  if (indexing_ == unknown)
-    indexing_ = manual;
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.context
-namespace std {
-  template<class Out, class charT>
-  class basic_format_context {
-    basic_format_args<basic_format_context> args_; // exposition only
-    Out out_;                                      // exposition only
-
-  public:
-    using iterator = Out;
-    using char_type = charT;
-    template<class T> using formatter_type = formatter<T, charT>;
-
-    basic_format_arg<basic_format_context> arg(size_t id) const;
-
-    iterator out();
-    void advance_to(iterator it);
-
-    // Implementation details:
-    using format_arg = basic_format_arg<basic_format_context>;
-    basic_format_context(Out out, basic_format_args<basic_format_context> args, fmt::detail::locale_ref)
-    : args_(args), out_(out) {}
-    detail::error_handler error_handler() const { return {}; }
-    basic_format_arg<basic_format_context> arg(fmt::basic_string_view<charT>) const {
-      return {}; // unused: named arguments are not supported yet
-    }
-    void on_error(const char* msg) { error_handler().on_error(msg); }
-  };
-}
-
-namespace std {
-template<class O, class charT>
-basic_format_arg<basic_format_context<O, charT>> basic_format_context<O, charT>::arg(size_t id) const { return args_.get(id); }
-
-template<class O, class charT>
-typename basic_format_context<O, charT>::iterator basic_format_context<O, charT>::out() { return out_; }
-
-template<class O, class charT>
-void basic_format_context<O, charT>::advance_to(typename basic_format_context<O, charT>::iterator it) { out_ = it; }
-}
-
-namespace std {
-namespace detail {
-template <typename T>
-constexpr bool is_standard_integer_v =
-    std::is_same_v<T, signed char> ||
-    std::is_same_v<T, short int> ||
-    std::is_same_v<T, int> ||
-    std::is_same_v<T, long int> ||
-    std::is_same_v<T, long long int>;
-
-template <typename T>
-constexpr bool is_standard_unsigned_integer_v =
-    std::is_same_v<T, unsigned char> ||
-    std::is_same_v<T, unsigned short int> ||
-    std::is_same_v<T, unsigned int> ||
-    std::is_same_v<T, unsigned long int> ||
-    std::is_same_v<T, unsigned long long int>;
-
-template <typename T, typename Char> struct formatter;
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.arg
-namespace std {
-  template<class Context>
-  class basic_format_arg {
-  public:
-    class handle;
-
-  private:
-    using char_type = typename Context::char_type;                       // exposition only
-
-    variant<monostate, bool, char_type,
-            int, unsigned int, long long int, unsigned long long int,
-            double, long double,
-            const char_type*, basic_string_view<char_type>,
-            const void*, handle> value;                                  // exposition only
-
-    template<typename T,
-      typename = enable_if_t<
-        std::is_same_v<T, bool> ||
-        std::is_same_v<T, char_type> ||
-        (std::is_same_v<T, char> && std::is_same_v<char_type, wchar_t>) ||
-        detail::is_standard_integer_v<T> ||
-        detail::is_standard_unsigned_integer_v<T> ||
-        sizeof(typename Context::template formatter_type<T>().format(declval<const T&>(), declval<Context&>())) != 0
-    >> explicit basic_format_arg(const T& v) noexcept; // exposition only
-    explicit basic_format_arg(float n) noexcept;                         // exposition only
-    explicit basic_format_arg(double n) noexcept;                        // exposition only
-    explicit basic_format_arg(long double n) noexcept;                   // exposition only
-    explicit basic_format_arg(const char_type* s);                       // exposition only
-
-    template<class traits>
-      explicit basic_format_arg(
-        basic_string_view<char_type, traits> s) noexcept;                // exposition only
-
-    template<class traits, class Allocator>
-      explicit basic_format_arg(
-        const basic_string<char_type, traits, Allocator>& s) noexcept;   // exposition only
-
-    explicit basic_format_arg(nullptr_t) noexcept;                       // exposition only
-
-    template<class T, typename = enable_if_t<is_void_v<T>>>
-      explicit basic_format_arg(const T* p) noexcept;                    // exposition only
-
-    // Fails due to a bug in clang
-    //template<class Visitor, class Ctx>
-    //  friend auto visit_format_arg(Visitor&& vis,
-    //                                    basic_format_arg<Ctx> arg);           // exposition only
-
-    friend auto get_value(basic_format_arg arg) {
-      return arg.value;
-    }
-
-    template <typename T, typename Char> friend struct detail::formatter;
-
-    template<class Ctx, class... Args>
-      friend format_arg_store<Ctx, Args...>
-        make_format_args(const Args&... args);                           // exposition only
-
-  public:
-    basic_format_arg() noexcept;
-
-    explicit operator bool() const noexcept;
-  };
-}
-
-namespace std {
-template<class Context>
-basic_format_arg<Context>::basic_format_arg() noexcept {}
-
-template<class Context>
-template<class T, typename> /* explicit */ basic_format_arg<Context>::basic_format_arg(const T& v) noexcept {
-  if constexpr (std::is_same_v<T, bool> || std::is_same_v<T, char_type>)
-    value = v;
-  else if constexpr (std::is_same_v<T, char> && std::is_same_v<char_type, wchar_t>)
-    value = static_cast<wchar_t>(v);
-  else if constexpr (detail::is_standard_integer_v<T> && sizeof(T) <= sizeof(int))
-    value = static_cast<int>(v);
-  else if constexpr (detail::is_standard_unsigned_integer_v<T> && sizeof(T) <= sizeof(unsigned))
-    value = static_cast<unsigned>(v);
-  else if constexpr (detail::is_standard_integer_v<T>)
-    value = static_cast<long long int>(v);
-  else if constexpr (detail::is_standard_unsigned_integer_v<T>)
-    value = static_cast<unsigned long long int>(v);
-  else if constexpr (sizeof(typename Context::template formatter_type<T>().format(declval<const T&>(), declval<Context&>())) != 0)
-    value = handle(v);
-}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(float n) noexcept
-  : value(static_cast<double>(n)) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(double n) noexcept
-  : value(n) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(long double n) noexcept
-  : value(n) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(const typename basic_format_arg<Context>::char_type* s)
-  : value(s) {
-  assert(s != nullptr);
-}
-
-template<class Context>
-template<class traits>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(basic_string_view<char_type, traits> s) noexcept
-  : value(s) {}
-
-template<class Context>
-template<class traits, class Allocator>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(
-    const basic_string<char_type, traits, Allocator>& s) noexcept
-  : value(basic_string_view<char_type>(s.data(), s.size())) {}
-
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(nullptr_t) noexcept
-  : value(static_cast<const void*>(nullptr)) {}
-
-template<class Context>
-template<class T, typename> /* explicit */ basic_format_arg<Context>::basic_format_arg(const T* p) noexcept
-  : value(p) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::operator bool() const noexcept {
-    return !holds_alternative<monostate>(value);
-}
-}
-
-namespace std {
-  template<class Context>
-  class basic_format_arg<Context>::handle {
-    const void* ptr_;                                         // exposition only
-    void (*format_)(basic_format_parse_context<char_type>&,
-                    Context&, const void*);                   // exposition only
-
-    template<class T> explicit handle(const T& val) noexcept; // exposition only
-
-    friend class basic_format_arg<Context>;                   // exposition only
-
-  public:
-    void format(basic_format_parse_context<char_type>&, Context& ctx) const;
-  };
-}
-
-namespace std {
-template<class Context>
-template<class T> /* explicit */ basic_format_arg<Context>::handle::handle(const T& val) noexcept
-  : ptr_(&val), format_([](basic_format_parse_context<char_type>& parse_ctx, Context& format_ctx, const void* ptr) {
-    typename Context::template formatter_type<T> f;
-    parse_ctx.advance_to(f.parse(parse_ctx));
-    format_ctx.advance_to(f.format(*static_cast<const T*>(ptr), format_ctx));
-  }) {}
-
-template<class Context>
-void basic_format_arg<Context>::handle::format(basic_format_parse_context<char_type>& parse_ctx, Context& format_ctx) const {
-  format_(parse_ctx, format_ctx, ptr_);
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.visit
-template<class Visitor, class Context>
-  auto visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg) {
-    return visit(vis, get_value(arg));
-  }
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.store
-namespace std {
-  template<class Context, class... Args>
-  struct format_arg_store { // exposition only
-    array<basic_format_arg<Context>, sizeof...(Args)> args;
-  };
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.basic_args
-namespace std {
-  template<class Context>
-  class basic_format_args {
-    size_t size_;                           // exposition only
-    const basic_format_arg<Context>* data_; // exposition only
-
-  public:
-    basic_format_args() noexcept;
-
-    template<class... Args>
-      basic_format_args(const format_arg_store<Context, Args...>& store) noexcept;
-
-    basic_format_arg<Context> get(size_t i) const noexcept;
-  };
-}
-
-namespace std {
-
-template<class Context>
-basic_format_args<Context>::basic_format_args() noexcept : size_(0) {}
-
-template<class Context>
-template<class... Args>
-  basic_format_args<Context>::basic_format_args(const format_arg_store<Context, Args...>& store) noexcept
-  : size_(sizeof...(Args)), data_(store.args.data()) {}
-
-template<class Context>
-basic_format_arg<Context> basic_format_args<Context>::get(size_t i) const noexcept {
-  return i < size_ ? data_[i] : basic_format_arg<Context>();
-}
-}
-
-namespace std {
-// https://fmt.dev/Text%20Formatting.html#format.make_args
-template<class Context /*= format_context*/, class... Args>
-  format_arg_store<Context, Args...> make_format_args(const Args&... args) {
-    return {basic_format_arg<Context>(args)...};
-  }
-
-// https://fmt.dev/Text%20Formatting.html#format.make_wargs
-template<class... Args>
-  format_arg_store<wformat_context, Args...> make_wformat_args(const Args&... args) {
-    return make_format_args<wformat_context>(args...);
-  }
-}
-
-namespace std {
-namespace detail {
-
-template <typename OutputIt, typename Char>
-class arg_formatter
-    : public fmt::detail::arg_formatter_base<OutputIt, Char, error_handler> {
- private:
-  using char_type = Char;
-  using base = fmt::detail::arg_formatter_base<OutputIt, Char, error_handler>;
-  using format_context = std::basic_format_context<OutputIt, Char>;
-  using parse_context = basic_format_parse_context<Char>;
-
-  parse_context* parse_ctx_;
-  format_context& ctx_;
-
- public:
-  using iterator = OutputIt;
-  using format_specs = typename base::format_specs;
-
-  /**
-    \rst
-    Constructs an argument formatter object.
-    *ctx* is a reference to the formatting context,
-    *spec* contains format specifier information for standard argument types.
-    \endrst
-   */
-  arg_formatter(format_context& ctx, parse_context* parse_ctx = nullptr, fmt::format_specs* spec = nullptr)
-      : base(ctx.out(), spec, {}), parse_ctx_(parse_ctx), ctx_(ctx) {}
-
-  using base::operator();
-
-  /** Formats an argument of a user-defined type. */
-  iterator operator()(typename std::basic_format_arg<format_context>::handle handle) {
-    handle.format(*parse_ctx_, ctx_);
-    return this->out();
-  }
-
-  iterator operator()(monostate) {
-    throw format_error("");
-  }
-};
-
-template <typename Context>
-inline fmt::detail::type get_type(basic_format_arg<Context> arg) {
-  return visit_format_arg([&] (auto val) {
-    using char_type = typename Context::char_type;
-    using T = decltype(val);
-    if (std::is_same_v<T, monostate>)
-      return fmt::detail::type::none_type;
-    if (std::is_same_v<T, bool>)
-      return fmt::detail::type::bool_type;
-    if (std::is_same_v<T, char_type>)
-      return fmt::detail::type::char_type;
-    if (std::is_same_v<T, int>)
-      return fmt::detail::type::int_type;
-    if (std::is_same_v<T, unsigned int>)
-      return fmt::detail::type::uint_type;
-    if (std::is_same_v<T, long long int>)
-      return fmt::detail::type::long_long_type;
-    if (std::is_same_v<T, unsigned long long int>)
-      return fmt::detail::type::ulong_long_type;
-    if (std::is_same_v<T, double>)
-      return fmt::detail::type::double_type;
-    if (std::is_same_v<T, long double>)
-      return fmt::detail::type::long_double_type;
-    if (std::is_same_v<T, const char_type*>)
-      return fmt::detail::type::cstring_type;
-    if (std::is_same_v<T, basic_string_view<char_type>>)
-      return fmt::detail::type::string_type;
-    if (std::is_same_v<T, const void*>)
-      return fmt::detail::type::pointer_type;
-    assert(get_value(arg).index() == 12);
-    return fmt::detail::type::custom_type;
-  }, arg);
-}
-
-template <typename Context>
-class custom_formatter {
- private:
-  using parse_context = basic_format_parse_context<typename Context::char_type>;
-  parse_context& parse_ctx_;
-  Context& format_ctx_;
-
- public:
-  custom_formatter(parse_context& parse_ctx, Context& ctx) : parse_ctx_(parse_ctx), format_ctx_(ctx) {}
-
-  bool operator()(typename basic_format_arg<Context>::handle h) const {
-    h.format(parse_ctx_, format_ctx_);
-    return true;
-  }
-
-  template <typename T> bool operator()(T) const { return false; }
-};
-
-template <typename ArgFormatter, typename Char, typename Context>
-struct format_handler : detail::error_handler {
-  using iterator = typename ArgFormatter::iterator;
-
-  format_handler(iterator out, basic_string_view<Char> str,
-                 basic_format_args<Context> format_args,
-                 fmt::detail::locale_ref loc)
-      : parse_ctx(str), context(out, format_args, loc) {}
-
-  void on_text(const Char* begin, const Char* end) {
-    auto size = fmt::detail::to_unsigned(end - begin);
-    auto out = context.out();
-    auto&& it = fmt::detail::reserve(out, size);
-    it = std::copy_n(begin, size, it);
-    context.advance_to(out);
-  }
-
-  int on_arg_id() { return parse_ctx.next_arg_id(); }
-  int on_arg_id(unsigned id) { return parse_ctx.check_arg_id(id), id; }
-  int on_arg_id(fmt::basic_string_view<Char>) { return 0; }
-
-  void on_replacement_field(int id, const Char* p) {
-    auto arg = context.arg(id);
-    parse_ctx.advance_to(parse_ctx.begin() + (p  - &*parse_ctx.begin()));
-    custom_formatter<Context> f(parse_ctx, context);
-    if (!visit_format_arg(f, arg))
-      context.advance_to(visit_format_arg(ArgFormatter(context, &parse_ctx), arg));
-  }
-
-  const Char* on_format_specs(int id, const Char* begin, const Char* end) {
-    auto arg = context.arg(id);
-    parse_ctx.advance_to(parse_ctx.begin() + (begin - &*parse_ctx.begin()));
-    custom_formatter<Context> f(parse_ctx, context);
-    if (visit_format_arg(f, arg)) return &*parse_ctx.begin();
-    fmt::basic_format_specs<Char> specs;
-    using fmt::detail::specs_handler;
-    using parse_context = basic_format_parse_context<Char>;
-    fmt::detail::specs_checker<specs_handler<parse_context, Context>> handler(
-        specs_handler<parse_context, Context>(specs, parse_ctx, context), get_type(arg));
-    begin = parse_format_specs(begin, end, handler);
-    if (begin == end || *begin != '}') on_error("missing '}' in format string");
-    parse_ctx.advance_to(parse_ctx.begin() + (begin - &*parse_ctx.begin()));
-    context.advance_to(visit_format_arg(ArgFormatter(context, &parse_ctx, &specs), arg));
-    return begin;
-  }
-
-  basic_format_parse_context<Char> parse_ctx;
-  Context context;
-};
-
-template <typename T, typename Char>
-struct formatter {
-  // Parses format specifiers stopping either at the end of the range or at the
-  // terminating '}'.
-  template <typename ParseContext>
-  FMT_CONSTEXPR typename ParseContext::iterator parse(ParseContext& ctx) {
-    namespace detail = fmt::detail;
-    typedef detail::dynamic_specs_handler<ParseContext> handler_type;
-    auto type = detail::mapped_type_constant<T, fmt::buffer_context<Char>>::value;
-    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                  type);
-    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
-    auto type_spec = specs_.type;
-    auto eh = ctx.error_handler();
-    switch (type) {
-    case detail::type::none_type:
-      FMT_ASSERT(false, "invalid argument type");
-      break;
-    case detail::type::int_type:
-    case detail::type::uint_type:
-    case detail::type::long_long_type:
-    case detail::type::ulong_long_type:
-    case detail::type::bool_type:
-      handle_int_type_spec(type_spec,
-                           detail::int_type_checker<decltype(eh)>(eh));
-      break;
-    case detail::type::char_type:
-      handle_char_specs(
-          &specs_, detail::char_specs_checker<decltype(eh)>(type_spec, eh));
-      break;
-    case detail::type::double_type:
-    case detail::type::long_double_type:
-      detail::parse_float_type_spec(specs_, eh);
-      break;
-    case detail::type::cstring_type:
-      detail::handle_cstring_type_spec(
-          type_spec, detail::cstring_type_checker<decltype(eh)>(eh));
-      break;
-    case detail::type::string_type:
-      detail::check_string_type_spec(type_spec, eh);
-      break;
-    case detail::type::pointer_type:
-      detail::check_pointer_type_spec(type_spec, eh);
-      break;
-    case detail::type::custom_type:
-      // Custom format specifiers should be checked in parse functions of
-      // formatter specializations.
-      break;
-    }
-    return it;
-  }
-
-  template <typename FormatContext>
-  auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
-    fmt::detail::handle_dynamic_spec<fmt::detail::width_checker>(
-        specs_.width, specs_.width_ref, ctx);
-    fmt::detail::handle_dynamic_spec<fmt::detail::precision_checker>(
-        specs_.precision, specs_.precision_ref, ctx);
-    using af = arg_formatter<typename FormatContext::iterator,
-                             typename FormatContext::char_type>;
-    return visit_format_arg(af(ctx, nullptr, &specs_),
-                            basic_format_arg<FormatContext>(val));
-  }
-
- private:
-  fmt::detail::dynamic_format_specs<Char> specs_;
-};
-}  // namespace detail
-
-// https://fmt.dev/Text%20Formatting.html#format.functions
-template<class... Args>
-  string format(string_view fmt, const Args&... args) {
-    return vformat(fmt, make_format_args(args...));
-  }
-
-template<class... Args>
-  wstring format(wstring_view fmt, const Args&... args) {
-    return vformat(fmt, make_wformat_args(args...));
-  }
-
-string vformat(string_view fmt, format_args args) {
-  fmt::memory_buffer mbuf;
-  fmt::detail::buffer<char>& buf = mbuf;
-  using af = detail::arg_formatter<fmt::format_context::iterator, char>;
-  detail::format_handler<af, char, format_context>
-    h(fmt::detail::buffer_appender<char>(buf), fmt, args, {});
-  fmt::detail::parse_format_string<false>(fmt::to_string_view(fmt), h);
-  return to_string(mbuf);
-}
-
-wstring vformat(wstring_view fmt, wformat_args args);
-
-template<class Out, class... Args>
-  Out format_to(Out out, string_view fmt, const Args&... args) {
-    using context = basic_format_context<Out, decltype(fmt)::value_type>;
-    return vformat_to(out, fmt, make_format_args<context>(args...));
-  }
-
-template<class Out, class... Args>
-  Out format_to(Out out, wstring_view fmt, const Args&... args) {
-    using context = basic_format_context<Out, decltype(fmt)::value_type>;
-    return vformat_to(out, fmt, make_format_args<context>(args...));
-  }
-
-template<class Out>
-  Out vformat_to(Out out, string_view fmt, format_args_t<fmt::type_identity_t<Out>, char> args) {
-    using af = detail::arg_formatter<Out, char>;
-    detail::format_handler<af, char, basic_format_context<Out, char>>
-      h(out, fmt, args, {});
-    fmt::detail::parse_format_string<false>(fmt::to_string_view(fmt), h);
-    return h.context.out();
-  }
-
-template<class Out>
-  Out vformat_to(Out out, wstring_view fmt, format_args_t<fmt::type_identity_t<Out>, wchar_t> args);
-
-template<class Out, class... Args>
-  format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                      string_view fmt, const Args&... args);
-template<class Out, class... Args>
-  format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                      wstring_view fmt, const Args&... args);
-
-template<class... Args>
-  size_t formatted_size(string_view fmt, const Args&... args);
-template<class... Args>
-  size_t formatted_size(wstring_view fmt, const Args&... args);
-
-#define charT char
-
-template<> struct formatter<charT, charT> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<char, wchar_t>;
-
-template<> struct formatter<charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<> struct formatter<const charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<size_t N> struct formatter<const charT[N], charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits, class Allocator>
-  struct formatter<basic_string<charT, traits, Allocator>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits>
-  struct formatter<basic_string_view<charT, traits>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template <> struct formatter<nullptr_t, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<const void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<bool, charT> : detail::formatter<bool, charT> {};
-
-template <> struct formatter<signed char, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<short, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<int, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), int, long long>, charT> {};
-template <> struct formatter<long long, charT> : detail::formatter<long long, charT> {};
-template <> struct formatter<unsigned char, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned short, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned int, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), unsigned, unsigned long long>, charT> {};
-template <> struct formatter<unsigned long long, charT> : detail::formatter<unsigned long long, charT> {};
-
-template <> struct formatter<float, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<double, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<long double, charT> : detail::formatter<long double, charT> {};
-
-#undef charT
-
-#define charT wchar_t
-
-template<> struct formatter<charT, charT> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<char, wchar_t> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<> struct formatter<const charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<size_t N> struct formatter<const charT[N], charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits, class Allocator>
-  struct formatter<std::basic_string<charT, traits, Allocator>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits>
-  struct formatter<std::basic_string_view<charT, traits>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template <> struct formatter<nullptr_t, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<const void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<bool, charT> : detail::formatter<bool, charT> {};
-
-template <> struct formatter<signed char, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<short, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<int, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), int, long long>, charT> {};
-template <> struct formatter<long long, charT> : detail::formatter<long long, charT> {};
-template <> struct formatter<unsigned char, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned short, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned int, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), unsigned, unsigned long long>, charT> {};
-template <> struct formatter<unsigned long long, charT> : detail::formatter<unsigned long long, charT> {};
-
-template <> struct formatter<float, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<double, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<long double, charT> : detail::formatter<long double, charT> {};
-
-#undef charT
-
-  template<> struct formatter<const wchar_t, char> {
-    formatter() = delete;
-  };
-}
-
-#endif  // FMT_FORMAT_

test/format-impl-test.cc

@@ -278,25 +278,22 @@ TEST(fp_test, get_round_direction) {
 }
 
 TEST(fp_test, fixed_handler) {
-  struct handler : fmt::detail::fixed_handler {
+  struct handler : fmt::detail::gen_digits_handler {
     char buffer[10];
-    handler(int prec = 0) : fmt::detail::fixed_handler() {
+    handler(int prec = 0) : fmt::detail::gen_digits_handler() {
       buf = buffer;
       precision = prec;
     }
   };
-  int exp = 0;
+  handler().on_digit('0', 100, 99, 0, false);
-  handler().on_digit('0', 100, 99, 0, exp, false);
+  EXPECT_THROW(handler().on_digit('0', 100, 100, 0, false), assertion_failure);
-  EXPECT_THROW(handler().on_digit('0', 100, 100, 0, exp, false),
-               assertion_failure);
   namespace digits = fmt::detail::digits;
-  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 10, exp, false), digits::error);
+  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 10, false), digits::error);
   // Check that divisor - error doesn't overflow.
-  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 101, exp, false), digits::error);
+  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 101, false), digits::error);
   // Check that 2 * error doesn't overflow.
   uint64_t max = max_value<uint64_t>();
-  EXPECT_EQ(handler(1).on_digit('0', max, 10, max - 1, exp, false),
+  EXPECT_EQ(handler(1).on_digit('0', max, 10, max - 1, false), digits::error);
-            digits::error);
 }
 
 TEST(fp_test, grisu_format_compiles_with_on_ieee_double) {

test/format-test.cc

@@ -370,11 +370,11 @@ TEST(format_test, escape) {
 }
 
 TEST(format_test, unmatched_braces) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{")), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("}")), format_error,
                    "unmatched '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0{}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0{}")), format_error,
                    "invalid format string");
 }
 
@@ -391,30 +391,30 @@ TEST(format_test, args_in_different_positions) {
 }
 
 TEST(format_test, arg_errors) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{")), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{?}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{?}")), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0")), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}")), format_error,
                    "argument not found");
-  EXPECT_THROW_MSG(fmt::format(runtime("{00}"), 42), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{00}"), 42), format_error,
                    "invalid format string");
 
   char format_str[buffer_size];
   safe_sprintf(format_str, "{%u", INT_MAX);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str)), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
                    "invalid format string");
   safe_sprintf(format_str, "{%u}", INT_MAX);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str)), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
                    "argument not found");
 
   safe_sprintf(format_str, "{%u", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str)), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
                    "invalid format string");
   safe_sprintf(format_str, "{%u}", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str)), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
                    "argument not found");
 }
 
@@ -458,24 +458,26 @@ TEST(format_test, named_arg) {
                         fmt::arg("i", 0), fmt::arg("j", 0), fmt::arg("k", 0),
                         fmt::arg("l", 0), fmt::arg("m", 0), fmt::arg("n", 0),
                         fmt::arg("o", 0), fmt::arg("p", 0)));
-  EXPECT_THROW_MSG(fmt::format(runtime("{a}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{a}")), format_error,
                    "argument not found");
-  EXPECT_THROW_MSG(fmt::format(runtime("{a}"), 42), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{a}"), 42), format_error,
                    "argument not found");
 }
 
 TEST(format_test, auto_arg_index) {
   EXPECT_EQ("abc", fmt::format("{}{}{}", 'a', 'b', 'c'));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0}{}"), 'a', 'b'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}{}"), 'a', 'b'), format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{}{0}"), 'a', 'b'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{}{0}"), 'a', 'b'), format_error,
                    "cannot switch from automatic to manual argument indexing");
   EXPECT_EQ("1.2", fmt::format("{:.{}}", 1.2345, 2));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0}:.{}"), 1.2345, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}:.{}"), 1.2345, 2),
+                   format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:.{0}}"), 1.2345, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.{0}}"), 1.2345, 2),
+                   format_error,
                    "cannot switch from automatic to manual argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{}")), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{}")), format_error,
                    "argument not found");
 }
 
@@ -533,9 +535,9 @@ TEST(format_test, center_align) {
 }
 
 TEST(format_test, fill) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{<5}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{<5}"), 'c'), format_error,
                    "invalid fill character '{'");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{<5}}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{<5}}"), 'c'), format_error,
                    "invalid fill character '{'");
   EXPECT_EQ("**42", fmt::format("{0:*>4}", 42));
   EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42));
@@ -554,80 +556,83 @@ TEST(format_test, fill) {
   EXPECT_EQ(std::string("\0\0\0*", 4),
             fmt::format(string_view("{:\0>4}", 6), '*'));
   EXPECT_EQ("жж42", fmt::format("{0:ж>4}", 42));
-  EXPECT_THROW_MSG(fmt::format(runtime("{:\x80\x80\x80\x80\x80>}"), 0),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:\x80\x80\x80\x80\x80>}"), 0),
-                   format_error, "missing '}' in format string");
+                   format_error, "invalid type specifier");
 }
 
 TEST(format_test, plus_sign) {
   EXPECT_EQ("+42", fmt::format("{0:+}", 42));
   EXPECT_EQ("-42", fmt::format("{0:+}", -42));
   EXPECT_EQ("+42", fmt::format("{0:+}", 42));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), 42u), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42u), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), 42ul), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ul), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42ll));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), 42ull), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ull), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42.0));
   EXPECT_EQ("+42", fmt::format("{0:+}", 42.0l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+"), 'c'), format_error,
                    "missing '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 'c'), format_error,
                    "invalid format specifier for char");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), "abc"), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), "abc"), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), reinterpret_cast<void*>(0x42)),
+  EXPECT_THROW_MSG(
-                   format_error, "format specifier requires numeric argument");
+      (void)fmt::format(runtime("{0:+}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
 }
 
 TEST(format_test, minus_sign) {
   EXPECT_EQ("42", fmt::format("{0:-}", 42));
   EXPECT_EQ("-42", fmt::format("{0:-}", -42));
   EXPECT_EQ("42", fmt::format("{0:-}", 42));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), 42u), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42u), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("42", fmt::format("{0:-}", 42l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), 42ul), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ul), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("42", fmt::format("{0:-}", 42ll));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), 42ull), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ull), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ("42", fmt::format("{0:-}", 42.0));
   EXPECT_EQ("42", fmt::format("{0:-}", 42.0l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-"), 'c'), format_error,
                    "missing '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 'c'), format_error,
                    "invalid format specifier for char");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), "abc"), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), "abc"), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), reinterpret_cast<void*>(0x42)),
+  EXPECT_THROW_MSG(
-                   format_error, "format specifier requires numeric argument");
+      (void)fmt::format(runtime("{0:-}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
 }
 
 TEST(format_test, space_sign) {
   EXPECT_EQ(" 42", fmt::format("{0: }", 42));
   EXPECT_EQ("-42", fmt::format("{0: }", -42));
   EXPECT_EQ(" 42", fmt::format("{0: }", 42));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), 42u), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42u), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), 42ul), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ul), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42ll));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), 42ull), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ull), format_error,
                    "format specifier requires signed argument");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42.0));
   EXPECT_EQ(" 42", fmt::format("{0: }", 42.0l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: "), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: "), 'c'), format_error,
                    "missing '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 'c'), format_error,
                    "invalid format specifier for char");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), "abc"), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), "abc"), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), reinterpret_cast<void*>(0x42)),
+  EXPECT_THROW_MSG(
-                   format_error, "format specifier requires numeric argument");
+      (void)fmt::format(runtime("{0: }"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
 }
 
 TEST(format_test, hash_flag) {
@@ -670,14 +675,15 @@ TEST(format_test, hash_flag) {
   EXPECT_EQ("0.", fmt::format("{:#.0f}", 0.01));
   EXPECT_EQ("0.50", fmt::format("{:#.2g}", 0.5));
   EXPECT_EQ("0.", fmt::format("{:#.0f}", 0.5));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:#"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#"), 'c'), format_error,
                    "missing '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:#}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), 'c'), format_error,
                    "invalid format specifier for char");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:#}"), "abc"), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), "abc"), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:#}"), reinterpret_cast<void*>(0x42)),
+  EXPECT_THROW_MSG(
-                   format_error, "format specifier requires numeric argument");
+      (void)fmt::format(runtime("{0:#}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
 }
 
 TEST(format_test, zero_flag) {
@@ -690,14 +696,14 @@ TEST(format_test, zero_flag) {
   EXPECT_EQ("00042", fmt::format("{0:05}", 42ull));
   EXPECT_EQ("-000042", fmt::format("{0:07}", -42.0));
   EXPECT_EQ("-000042", fmt::format("{0:07}", -42.0l));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:0"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:0"), 'c'), format_error,
                    "missing '}' in format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:05}"), 'c'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), 'c'), format_error,
                    "invalid format specifier for char");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:05}"), "abc"), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), "abc"), format_error,
                    "format specifier requires numeric argument");
   EXPECT_THROW_MSG(
-      fmt::format(runtime("{0:05}"), reinterpret_cast<void*>(0x42)),
+      (void)fmt::format(runtime("{0:05}"), reinterpret_cast<void*>(0x42)),
       format_error, "format specifier requires numeric argument");
 }
 
@@ -705,19 +711,19 @@ TEST(format_test, width) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:%u", UINT_MAX);
   increment(format_str + 3);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
 
   safe_sprintf(format_str, "{0:%u", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
   safe_sprintf(format_str, "{0:%u}", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
   EXPECT_EQ(" -42", fmt::format("{0:4}", -42));
   EXPECT_EQ("   42", fmt::format("{0:5}", 42u));
@@ -742,47 +748,47 @@ TEST(format_test, runtime_width) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:{%u", UINT_MAX);
   increment(format_str + 4);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "invalid format string");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "argument not found");
   format_str[size + 1] = '}';
   format_str[size + 2] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{"), 0), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{}"), 0), format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{?}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{?}}"), 0), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{0:}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{0:}}"), 0), format_error,
                    "invalid format string");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, -1), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, -1), format_error,
                    "negative width");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1u)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1u)),
                    format_error, "number is too big");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, -1l), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, -1l), format_error,
                    "negative width");
   if (fmt::detail::const_check(sizeof(long) > sizeof(int))) {
     long value = INT_MAX;
-    EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, (value + 1)),
+    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (value + 1)),
                      format_error, "number is too big");
   }
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1ul)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1ul)),
                    format_error, "number is too big");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, '0'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, '0'), format_error,
                    "width is not integer");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{1}}"), 0, 0.0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, 0.0), format_error,
                    "width is not integer");
 
   EXPECT_EQ(" -42", fmt::format("{0:{1}}", -42, 4));
@@ -803,53 +809,53 @@ TEST(format_test, precision) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:.%u", UINT_MAX);
   increment(format_str + 4);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
 
   safe_sprintf(format_str, "{0:.%u", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
   safe_sprintf(format_str, "{0:.%u}", INT_MAX + 1u);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "number is too big");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:."), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:."), 0), format_error,
                    "missing precision specifier");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.}"), 0), format_error,
                    "missing precision specifier");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2"), 0), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42u), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42u), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42u), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42u), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42l), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42l), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42l), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42l), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42ul), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ul), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42ul), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ul), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42ll), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ll), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42ll), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ll), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2}"), 42ull), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ull), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.2f}"), 42ull), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ull), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:3.0}"), 'x'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.0}"), 'x'), format_error,
                    "precision not allowed for this argument type");
   EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345));
   EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345l));
@@ -866,6 +872,23 @@ TEST(format_test, precision) {
       "117102665855668676818703956031062493194527159149245532930545654440112748"
       "012970999954193198940908041656332452475714786901472678015935523861155013"
       "480352649347201937902681071074917033322268447533357208324319361e-324");
+  EXPECT_EQ(
+      fmt::format("{:.1074f}", 1.1125369292536e-308),
+      "0.0000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000111253692925360019747947051741965785554081512200979"
+      "355021686109411883779182127659725163430929750364498219730822952552570601"
+      "152163505899912777129583674906301179059298598412303893909188340988729019"
+      "014361467448914817838555156840459458527907308695109202499990850735085304"
+      "478476991912072201449236975063640913461919914396877093174125167509869762"
+      "482369631100360266123742648159508919592746619553246586039571522788247697"
+      "156360766271842991667238355464496455107749716934387136380536472531224398"
+      "559833794807213172371254492216255558078524900147957309382830827524104234"
+      "530961756787819847850302379672357738807808384667004752163416921762619527"
+      "462847642037420991432005657440259928195996762610375541867198059294212446"
+      "81962777939941034720757232455434770912461317493580281734466552734375");
 
   std::string outputs[] = {
       "-0X1.41FE3FFE71C9E000000000000000000000000000000000000000000000000000000"
@@ -903,13 +926,16 @@ TEST(format_test, precision) {
   EXPECT_EQ("1.0e-34", fmt::format("{:.1e}", 1e-34));
 
   EXPECT_THROW_MSG(
-      fmt::format(runtime("{0:.2}"), reinterpret_cast<void*>(0xcafe)),
+      (void)fmt::format(runtime("{0:.2}"), reinterpret_cast<void*>(0xcafe)),
       format_error, "precision not allowed for this argument type");
   EXPECT_THROW_MSG(
-      fmt::format(runtime("{0:.2f}"), reinterpret_cast<void*>(0xcafe)),
+      (void)fmt::format(runtime("{0:.2f}"), reinterpret_cast<void*>(0xcafe)),
       format_error, "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.{}e}"), 42.0,
+                                     fmt::detail::max_value<int>()),
+                   format_error, "number is too big");
   EXPECT_THROW_MSG(
-      fmt::format(runtime("{:.{}e}"), 42.0, fmt::detail::max_value<int>()),
+      (void)fmt::format("{:.2147483646f}", -2.2121295195081227E+304),
       format_error, "number is too big");
 
   EXPECT_EQ("st", fmt::format("{0:.2}", "str"));
@@ -919,86 +945,97 @@ TEST(format_test, runtime_precision) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:.{%u", UINT_MAX);
   increment(format_str + 5);
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "invalid format string");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "argument not found");
   format_str[size + 1] = '}';
   format_str[size + 2] = 0;
-  EXPECT_THROW_MSG(fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{"), 0), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{}"), 0), format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{?}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{?}}"), 0), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}"), 0, 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}"), 0, 0), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{0:}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{0:}}"), 0), format_error,
                    "invalid format string");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, -1), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1), format_error,
                    "negative precision");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1u)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1u)),
                    format_error, "number is too big");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, -1l), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1l), format_error,
                    "negative precision");
   if (fmt::detail::const_check(sizeof(long) > sizeof(int))) {
     long value = INT_MAX;
-    EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, (value + 1)),
+    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (value + 1)),
                      format_error, "number is too big");
   }
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1ul)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1ul)),
                    format_error, "number is too big");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, '0'), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, '0'), format_error,
                    "precision is not integer");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 0, 0.0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, 0.0), format_error,
                    "precision is not integer");
 
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42, 2), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42, 2), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42u, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42u, 2), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42u, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42u, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42l, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42l, 2), format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42l, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42l, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42ul, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ul, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42ul, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ul, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42ll, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ll, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42ll, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ll, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}}"), 42ull, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ull, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:.{1}f}"), 42ull, 2), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ull, 2),
+                   format_error,
                    "precision not allowed for this argument type");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:3.{1}}"), 'x', 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.{1}}"), 'x', 0),
+                   format_error,
                    "precision not allowed for this argument type");
   EXPECT_EQ("1.2", fmt::format("{0:.{1}}", 1.2345, 2));
   EXPECT_EQ("1.2", fmt::format("{1:.{0}}", 2, 1.2345l));
 
-  EXPECT_THROW_MSG(
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"),
-      fmt::format(runtime("{0:.{1}}"), reinterpret_cast<void*>(0xcafe), 2),
+                                     reinterpret_cast<void*>(0xcafe), 2),
-      format_error, "precision not allowed for this argument type");
+                   format_error,
-  EXPECT_THROW_MSG(
+                   "precision not allowed for this argument type");
-      fmt::format(runtime("{0:.{1}f}"), reinterpret_cast<void*>(0xcafe), 2),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"),
-      format_error, "precision not allowed for this argument type");
+                                     reinterpret_cast<void*>(0xcafe), 2),
+                   format_error,
+                   "precision not allowed for this argument type");
 
   EXPECT_EQ("st", fmt::format("{0:.{1}}", "str", 2));
 }
@@ -1029,15 +1066,15 @@ void check_unknown_types(const T& value, const char* types, const char*) {
     if (std::strchr(types, c) || std::strchr(special, c) || !c) continue;
     safe_sprintf(format_str, "{0:10%c}", c);
     const char* message = "invalid type specifier";
-    EXPECT_THROW_MSG(fmt::format(runtime(format_str), value), format_error,
+    EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), value),
-                     message)
+                     format_error, message)
         << format_str << " " << message;
   }
 }
 
 TEST(format_test, format_int) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:v"), 42), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:v"), 42), format_error,
-                   "missing '}' in format string");
+                   "invalid type specifier");
   check_unknown_types(42, "bBdoxXnLc", "integer");
   EXPECT_EQ("x", fmt::format("{:c}", static_cast<int>('x')));
 }
@@ -1345,26 +1382,10 @@ TEST(format_test, format_cstring) {
   char nonconst[] = "nonconst";
   EXPECT_EQ("nonconst", fmt::format("{0}", nonconst));
   EXPECT_THROW_MSG(
-      fmt::format(runtime("{0}"), static_cast<const char*>(nullptr)),
+      (void)fmt::format(runtime("{0}"), static_cast<const char*>(nullptr)),
       format_error, "string pointer is null");
 }
 
-TEST(format_test, format_schar_string) {
-  signed char str[] = "test";
-  EXPECT_EQ("test", fmt::format("{0:s}", str));
-  const signed char* const_str = str;
-  EXPECT_EQ("test", fmt::format("{0:s}", const_str));
-}
-
-TEST(format_test, format_uchar_string) {
-  unsigned char str[] = "test";
-  EXPECT_EQ("test", fmt::format("{0:s}", str));
-  const unsigned char* const_str = str;
-  EXPECT_EQ("test", fmt::format("{0:s}", const_str));
-  unsigned char* ptr = str;
-  EXPECT_EQ("test", fmt::format("{0:s}", ptr));
-}
-
 void function_pointer_test(int, double, std::string) {}
 
 TEST(format_test, format_pointer) {
@@ -1390,6 +1411,8 @@ TEST(format_test, format_pointer) {
 
 TEST(format_test, format_string) {
   EXPECT_EQ("test", fmt::format("{0}", std::string("test")));
+  EXPECT_THROW((void)fmt::format(fmt::runtime("{:x}"), std::string("test")),
+               fmt::format_error);
 }
 
 TEST(format_test, format_string_view) {
@@ -1479,7 +1502,7 @@ template <> struct formatter<Answer> : formatter<int> {
 FMT_END_NAMESPACE
 
 TEST(format_test, format_custom) {
-  EXPECT_THROW_MSG(fmt::format(runtime("{:s}"), date(2012, 12, 9)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:s}"), date(2012, 12, 9)),
                    format_error, "unknown format specifier");
   EXPECT_EQ("42", fmt::format("{0}", Answer()));
   EXPECT_EQ("0042", fmt::format("{:04}", Answer()));
@@ -1556,8 +1579,9 @@ TEST(format_test, format_examples) {
             fmt::format("int: {0:d};  hex: {0:#x};  oct: {0:#o}", 42));
 
   EXPECT_EQ("The answer is 42", fmt::format("The answer is {}", 42));
-  EXPECT_THROW_MSG(fmt::format(runtime("The answer is {:d}"), "forty-two"),
+  EXPECT_THROW_MSG(
-                   format_error, "invalid type specifier");
+      (void)fmt::format(runtime("The answer is {:d}"), "forty-two"),
+      format_error, "invalid type specifier");
 
   EXPECT_WRITE(
       stdout, fmt::print("{}", std::numeric_limits<double>::infinity()), "inf");
@@ -1593,6 +1617,11 @@ TEST(format_test, bytes) {
   EXPECT_EQ(10, s.size());
 }
 
+TEST(format_test, group_digits_view) {
+  EXPECT_EQ(fmt::format("{}", fmt::group_digits(10000000)), "10,000,000");
+  EXPECT_EQ(fmt::format("{:8}", fmt::group_digits(1000)), "   1,000");
+}
+
 enum test_enum { foo, bar };
 
 TEST(format_test, join) {
@@ -1716,6 +1745,21 @@ TEST(format_test, custom_format_compile_time_string) {
 
 using namespace fmt::literals;
 
+#  if FMT_GCC_VERSION
+#    define FMT_CHECK_DEPRECATED_UDL_FORMAT 1
+#  elif FMT_CLANG_VERSION && defined(__has_warning)
+#    if __has_warning("-Wdeprecated-declarations")
+#      define FMT_CHECK_DEPRECATED_UDL_FORMAT 1
+#    endif
+#  endif
+#  ifndef FMT_CHECK_DEPRECATED_UDL_FORMAT
+#    define FMT_CHECK_DEPRECATED_UDL_FORMAT 0
+#  endif
+
+#  if FMT_CHECK_DEPRECATED_UDL_FORMAT
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 TEST(format_test, format_udl) {
   EXPECT_EQ("{}c{}"_format("ab", 1), fmt::format("{}c{}", "ab", 1));
   EXPECT_EQ("foo"_format(), "foo");
@@ -1723,6 +1767,9 @@ TEST(format_test, format_udl) {
   EXPECT_EQ("{}"_format(date(2015, 10, 21)), "2015-10-21");
 }
 
+#    pragma GCC diagnostic pop
+#  endif
+
 TEST(format_test, named_arg_udl) {
   auto udl_a = fmt::format("{first}{second}{first}{third}", "first"_a = "abra",
                            "second"_a = "cad", "third"_a = 99);
@@ -1775,21 +1822,21 @@ TEST(format_test, dynamic_formatter) {
   EXPECT_EQ("42", fmt::format("{:d}", num));
   EXPECT_EQ("foo", fmt::format("{:s}", str));
   EXPECT_EQ(" 42 foo ", fmt::format("{:{}} {:{}}", num, 3, str, 4));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:{}}"), num), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{}}"), num), format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:{0}}"), num), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:{0}}"), num), format_error,
                    "cannot switch from automatic to manual argument indexing");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:+}"), str), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:+}"), str), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:-}"), str), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:-}"), str), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{: }"), str), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{: }"), str), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:#}"), str), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:#}"), str), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:0}"), str), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:0}"), str), format_error,
                    "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{:.2}"), num), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.2}"), num), format_error,
                    "precision not allowed for this argument type");
 }
 
@@ -1813,13 +1860,20 @@ struct formatter<adl_test::fmt::detail::foo> : formatter<std::string> {
 };
 FMT_END_NAMESPACE
 
-TEST(format_test, to_string) {
+struct convertible_to_int {
-  EXPECT_EQ("42", fmt::to_string(42));
+  operator int() const { return value; }
-  EXPECT_EQ("0x1234", fmt::to_string(reinterpret_cast<void*>(0x1234)));
-  EXPECT_EQ("foo", fmt::to_string(adl_test::fmt::detail::foo()));
 
-  enum test_enum2 : unsigned char { test_value };
+  int value = 42;
-  EXPECT_EQ("0", fmt::to_string(test_value));
+};
+
+TEST(format_test, to_string) {
+  EXPECT_EQ(fmt::to_string(42), "42");
+  EXPECT_EQ(fmt::to_string(reinterpret_cast<void*>(0x1234)), "0x1234");
+  EXPECT_EQ(fmt::to_string(adl_test::fmt::detail::foo()), "foo");
+  EXPECT_EQ(fmt::to_string(convertible_to_int()), "42");
+
+  enum foo : unsigned char { zero };
+  EXPECT_EQ(fmt::to_string(zero), "0");
 }
 
 TEST(format_test, output_iterators) {

test/fuzzing/CMakeLists.txt

@@ -25,6 +25,6 @@ function(add_fuzzer source)
   target_compile_features(${name} PRIVATE cxx_generic_lambdas)
 endfunction()
 
-foreach (source chrono-duration.cc float.cc named-arg.cc one-arg.cc two-args.cc)
+foreach (source chrono-duration.cc chrono-timepoint.cc float.cc named-arg.cc one-arg.cc two-args.cc)
   add_fuzzer(${source})
 endforeach ()

test/fuzzing/build.sh

@@ -22,6 +22,8 @@ here=$(pwd)
 CXXFLAGSALL="-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION= -g"
 CMAKEFLAGSALL="$root -GNinja -DCMAKE_BUILD_TYPE=Debug -DFMT_DOC=Off -DFMT_TEST=Off -DFMT_FUZZ=On -DCMAKE_CXX_STANDARD=17"
 
+CLANG=clang++-11
+
 # For performance analysis of the fuzzers.
 builddir=$here/build-fuzzers-perfanalysis
 mkdir -p $builddir
@@ -37,7 +39,7 @@ cmake --build $builddir
 builddir=$here/build-fuzzers-ossfuzz
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \
@@ -50,7 +52,7 @@ cmake --build $builddir
 builddir=$here/build-fuzzers-libfuzzer
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link,address,undefined" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \
@@ -62,7 +64,7 @@ cmake --build $builddir
 builddir=$here/build-fuzzers-fast
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link -O3" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \

test/fuzzing/chrono-duration.cc

@@ -1,9 +1,10 @@
 // Copyright (c) 2019, Paul Dreik
 // For the license information refer to format.h.
 
-#include <cstdint>
 #include <fmt/chrono.h>
 
+#include <cstdint>
+
 #include "fuzzer-common.h"
 
 template <typename Period, typename Rep>
@@ -13,8 +14,8 @@ void invoke_inner(fmt::string_view format_str, Rep rep) {
 #if FMT_FUZZ_FORMAT_TO_STRING
     std::string message = fmt::format(format_str, value);
 #else
-    fmt::memory_buffer buf;
+    auto buf = fmt::memory_buffer();
-    fmt::format_to(buf, format_str, value);
+    fmt::format_to(std::back_inserter(buf), format_str, value);
 #endif
   } catch (std::exception&) {
   }
@@ -86,7 +87,7 @@ void invoke_outer(const uint8_t* data, size_t size, int period) {
 }
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  if (size <= 4)  return 0;
+  if (size <= 4) return 0;
 
   const auto representation = data[0];
   const auto period = data[1];

test/fuzzing/chrono-timepoint.cc

@@ -0,0 +1,32 @@
+// Copyright (c) 2021, Paul Dreik
+// For license information refer to format.h.
+#include <fmt/chrono.h>
+
+#include "fuzzer-common.h"
+
+/*
+ * a fuzzer for the chrono timepoints formatters
+ * C is a clock (std::chrono::system_clock etc)
+ */
+template <typename C> void doit(const uint8_t* data, size_t size) {
+  using Rep = typename C::time_point::rep;
+  constexpr auto N = sizeof(Rep);
+  if (size < N) return;
+
+  const auto x = assign_from_buf<Rep>(data);
+  typename C::duration dur{x};
+  typename C::time_point timepoint{dur};
+  data += N;
+  size -= N;
+  data_to_string format_str(data, size);
+
+  std::string message = fmt::format(format_str.get(), timepoint);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  try {
+    doit<std::chrono::system_clock>(data, size);
+  } catch (...) {
+  }
+  return 0;
+}

test/fuzzing/float.cc

@@ -1,17 +1,18 @@
 // A fuzzer for floating-point formatter.
 // For the license information refer to format.h.
 
+#include <fmt/format.h>
+
 #include <cstdint>
 #include <cstdlib>
-#include <stdexcept>
 #include <limits>
-#include <fmt/format.h>
+#include <stdexcept>
 
 #include "fuzzer-common.h"
 
 void check_round_trip(fmt::string_view format_str, double value) {
   auto buffer = fmt::memory_buffer();
-  fmt::format_to(buffer, format_str, value);
+  fmt::format_to(std::back_inserter(buffer), format_str, value);
 
   if (std::isnan(value)) {
     auto nan = std::signbit(value) ? "-nan" : "nan";
@@ -24,8 +25,7 @@ void check_round_trip(fmt::string_view format_str, double value) {
   char* ptr = nullptr;
   if (std::strtod(buffer.data(), &ptr) != value)
     throw std::runtime_error("round trip failure");
-  if (ptr + 1 != buffer.end())
+  if (ptr + 1 != buffer.end()) throw std::runtime_error("unparsed output");
-    throw std::runtime_error("unparsed output");
 }
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {

test/fuzzing/fuzzer-common.h

@@ -4,12 +4,12 @@
 #ifndef FUZZER_COMMON_H
 #define FUZZER_COMMON_H
 
-#include <cstdint>      // std::uint8_t
-#include <cstring>      // memcpy
-#include <vector>
-
 #include <fmt/core.h>
 
+#include <cstdint>  // std::uint8_t
+#include <cstring>  // memcpy
+#include <vector>
+
 // One can format to either a string, or a buffer. The latter is faster, but
 // one may be interested in formatting to a string instead to verify it works
 // as intended. To avoid a combinatoric explosion, select this at compile time
@@ -56,7 +56,9 @@ struct data_to_string {
 
   data_to_string(const uint8_t* data, size_t size, bool add_terminator = false)
       : buffer(size + (add_terminator ? 1 : 0)) {
-    std::memcpy(buffer.data(), data, size);
+    if (size) {
+      std::memcpy(buffer.data(), data, size);
+    }
   }
 
   fmt::string_view get() const { return {buffer.data(), buffer.size()}; }

test/fuzzing/named-arg.cc

@@ -1,10 +1,11 @@
 // Copyright (c) 2019, Paul Dreik
 // For the license information refer to format.h.
 
+#include <fmt/chrono.h>
+
 #include <cstdint>
 #include <type_traits>
 #include <vector>
-#include <fmt/chrono.h>
 
 #include "fuzzer-common.h"
 
@@ -25,10 +26,11 @@ void invoke_fmt(const uint8_t* data, size_t size, unsigned arg_name_size) {
   try {
 #if FMT_FUZZ_FORMAT_TO_STRING
     std::string message =
-      fmt::format(format_str.get(), fmt::arg(arg_name.data(), value));
+        fmt::format(format_str.get(), fmt::arg(arg_name.data(), value));
 #else
     fmt::memory_buffer out;
-    fmt::format_to(out, format_str.get(), fmt::arg(arg_name.data(), value));
+    fmt::format_to(std::back_inserter(out), format_str.get(),
+                   fmt::arg(arg_name.data(), value));
 #endif
   } catch (std::exception&) {
   }

test/fuzzing/one-arg.cc

@@ -1,17 +1,18 @@
 // Copyright (c) 2019, Paul Dreik
 // For the license information refer to format.h.
 
+#include <fmt/chrono.h>
+
 #include <cstdint>
 #include <exception>
-#include <fmt/chrono.h>
 
 #include "fuzzer-common.h"
 
-template <typename T, typename Repr>
+template <typename T, typename Repr> const T* from_repr(const Repr& r) {
-const T* from_repr(const Repr& r) { return &r; }
+  return &r;
+}
 
-template <>
+template <> const std::tm* from_repr<std::tm>(const std::time_t& t) {
-const std::tm* from_repr<std::tm>(const std::time_t& t) {
   return std::localtime(&t);
 }
 

test/fuzzing/two-args.cc

@@ -1,10 +1,11 @@
 // Copyright (c) 2019, Paul Dreik
 // For the license information refer to format.h.
 
+#include <fmt/format.h>
+
 #include <cstdint>
 #include <exception>
 #include <string>
-#include <fmt/format.h>
 
 #include "fuzzer-common.h"
 

test/gtest-extra.cc

@@ -32,11 +32,10 @@ output_redirect::~output_redirect() FMT_NOEXCEPT {
 }
 
 void output_redirect::flush() {
-#  if EOF != -1
-#    error "FMT_RETRY assumes return value of -1 indicating failure"
-#  endif
   int result = 0;
-  FMT_RETRY(result, fflush(file_));
+  do {
+    result = fflush(file_);
+  } while (result == EOF && errno == EINTR);
   if (result != 0) throw fmt::system_error(errno, "cannot flush stream");
 }
 

test/gtest-extra.h

@@ -12,7 +12,12 @@
 
 #include <string>
 
-#include "fmt/os.h"
+#ifdef FMT_MODULE_TEST
+import fmt;
+#else
+#  include "fmt/os.h"
+#endif  // FMG_MODULE_TEST
+
 #include "gmock/gmock.h"
 
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
@@ -129,6 +134,7 @@ class suppress_assert {
   ~suppress_assert() {
     _set_invalid_parameter_handler(original_handler_);
     _CrtSetReportMode(_CRT_ASSERT, original_report_mode_);
+    (void)original_report_mode_;
   }
 };
 

test/gtest/CMakeLists.txt

@@ -17,6 +17,13 @@ else ()
   target_compile_definitions(gtest PUBLIC GTEST_HAS_PTHREAD=0)
 endif ()
 
+# Workaround GTest bug https://github.com/google/googletest/issues/705.
+check_cxx_compiler_flag(
+  -fno-delete-null-pointer-checks HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
+if (HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
+  target_compile_options(gtest PUBLIC -fno-delete-null-pointer-checks)
+endif ()
+
 if (MSVC)
   # Disable MSVC warnings of _CRT_INSECURE_DEPRECATE functions.
   target_compile_definitions(gtest PRIVATE _CRT_SECURE_NO_WARNINGS)

test/header-only-test.cc

@@ -1,7 +1,11 @@
 // Header-only configuration test
 
 #include "fmt/core.h"
+#include "fmt/ostream.h"
+#include "gtest/gtest.h"
 
 #ifndef FMT_HEADER_ONLY
 #  error "Not in the header-only mode."
 #endif
+
+TEST(header_only_test, format) { EXPECT_EQ(fmt::format("foo"), "foo"); }

test/module-test.cc

@@ -15,6 +15,8 @@
 #  define FMT_HIDE_MODULE_BUGS
 #endif
 
+#define FMT_MODULE_TEST
+
 #include <bit>
 #include <chrono>
 #include <exception>
@@ -35,18 +37,30 @@
 #  define FMT_USE_FCNTL 0
 #endif
 #define FMT_NOEXCEPT noexcept
+#if defined(_WIN32) && !defined(__MINGW32__)
+#  define FMT_POSIX(call) _##call
+#else
+#  define FMT_POSIX(call) call
+#endif
+#define FMT_OS_H_  // don't pull in os.h directly or indirectly
 
 import fmt;
 
 // check for macros leaking from BMI
 static bool macro_leaked =
-#if defined(FMT_CORE_H_) || defined(FMT_FORMAT_H)
+#if defined(FMT_CORE_H_) || defined(FMT_FORMAT_H_)
     true;
 #else
     false;
 #endif
 
-#include "gtest-extra.h"
+// Include sources to pick up functions and classes from the module rather than
+// from the non-modular library which is baked into the 'test-main' library.
+// This averts linker problems:
+// - strong ownership model: missing linker symbols
+// - weak ownership model: duplicate linker symbols
+#include "gtest-extra.cc"
+#include "util.cc"
 
 // an implicitly exported namespace must be visible [module.interface]/2.2
 TEST(module_test, namespace) {
@@ -62,8 +76,10 @@ bool oops_detail_namespace_is_visible;
 namespace fmt {
 bool namespace_detail_invisible() {
 #if defined(FMT_HIDE_MODULE_BUGS) && defined(_MSC_FULL_VER) && \
-    _MSC_FULL_VER <= 192930129
+    ((_MSC_VER == 1929 && _MSC_FULL_VER <= 192930136) ||       \
-  // bug in msvc up to 16.11-pre1:
+     (_MSC_VER == 1930 && _MSC_FULL_VER <= 193030704))
+  // bug in msvc up to 16.11.5 / 17.0-pre5:
+
   // the namespace is visible even when it is neither
   // implicitly nor explicitly exported
   return true;
@@ -83,8 +99,8 @@ TEST(module_test, detail_namespace) {
 // macros must not be imported from a *named* module  [cpp.import]/5.1
 TEST(module_test, macros) {
 #if defined(FMT_HIDE_MODULE_BUGS) && defined(_MSC_FULL_VER) && \
-    _MSC_FULL_VER <= 192930129
+    _MSC_FULL_VER <= 192930130
-  // bug in msvc up to 16.11-pre1:
+  // bug in msvc up to 16.11-pre2:
   // include-guard macros leak from BMI
   // and even worse: they cannot be #undef-ined
   macro_leaked = false;
@@ -442,8 +458,7 @@ TEST(module_test, time_duration) {
 }
 
 TEST(module_test, weekday) {
-  EXPECT_EQ("Monday",
+  EXPECT_EQ("Mon", fmt::format(std::locale::classic(), "{}", fmt::weekday(1)));
-            std::format(std::locale::classic(), "{:%A}", fmt::weekday(1)));
 }
 
 TEST(module_test, to_string_view) {

test/noexception-test.cc

@@ -0,0 +1,18 @@
+// Formatting library for C++ - Noexception tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/args.h"
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/compile.h"
+#include "fmt/core.h"
+#include "fmt/format.h"
+#include "fmt/os.h"
+#include "fmt/ostream.h"
+#include "fmt/printf.h"
+#include "fmt/ranges.h"
+#include "fmt/xchar.h"

test/os-test.cc

@@ -41,9 +41,9 @@ TEST(util_test, utf16_to_utf8_empty_string) {
 }
 
 template <typename Converter, typename Char>
-void check_utf_conversion_error(
+void check_utf_conversion_error(const char* message,
-    const char* message,
+                                fmt::basic_string_view<Char> str =
-    fmt::basic_string_view<Char> str = fmt::basic_string_view<Char>(0, 1)) {
+                                    fmt::basic_string_view<Char>(nullptr, 1)) {
   fmt::memory_buffer out;
   fmt::detail::format_windows_error(out, ERROR_INVALID_PARAMETER, message);
   auto error = std::system_error(std::error_code());
@@ -63,7 +63,7 @@ TEST(util_test, utf16_to_utf8_error) {
 
 TEST(util_test, utf16_to_utf8_convert) {
   fmt::detail::utf16_to_utf8 u;
-  EXPECT_EQ(ERROR_INVALID_PARAMETER, u.convert(wstring_view(0, 1)));
+  EXPECT_EQ(ERROR_INVALID_PARAMETER, u.convert(wstring_view(nullptr, 1)));
   EXPECT_EQ(ERROR_INVALID_PARAMETER,
             u.convert(wstring_view(L"foo", INT_MAX + 1u)));
 }
@@ -81,12 +81,12 @@ TEST(os_test, format_std_error_code) {
 }
 
 TEST(os_test, format_windows_error) {
-  LPWSTR message = 0;
+  LPWSTR message = nullptr;
   auto result = FormatMessageW(
       FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
           FORMAT_MESSAGE_IGNORE_INSERTS,
-      0, ERROR_FILE_EXISTS, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+      nullptr, ERROR_FILE_EXISTS, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-      reinterpret_cast<LPWSTR>(&message), 0, 0);
+      reinterpret_cast<LPWSTR>(&message), 0, nullptr);
   fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
   LocalFree(message);
   fmt::memory_buffer actual_message;
@@ -97,17 +97,17 @@ TEST(os_test, format_windows_error) {
 }
 
 TEST(os_test, format_long_windows_error) {
-  LPWSTR message = 0;
+  LPWSTR message = nullptr;
   // this error code is not available on all Windows platforms and
   // Windows SDKs, so do not fail the test if the error string cannot
   // be retrieved.
   int provisioning_not_allowed = 0x80284013L;  // TBS_E_PROVISIONING_NOT_ALLOWED
-  auto result = FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+  auto result = FormatMessageW(
-                                   FORMAT_MESSAGE_FROM_SYSTEM |
+      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
-                                   FORMAT_MESSAGE_IGNORE_INSERTS,
+          FORMAT_MESSAGE_IGNORE_INSERTS,
-                               0, static_cast<DWORD>(provisioning_not_allowed),
+      nullptr, static_cast<DWORD>(provisioning_not_allowed),
-                               MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-                               reinterpret_cast<LPWSTR>(&message), 0, 0);
+      reinterpret_cast<LPWSTR>(&message), 0, nullptr);
   if (result == 0) {
     LocalFree(message);
     return;
@@ -336,6 +336,14 @@ TEST(ostream_test, truncate) {
   EXPECT_EQ("foo", read(in, 4));
 }
 
+TEST(ostream_test, flush) {
+  auto out = fmt::output_file("test-file");
+  out.print("x");
+  out.flush();
+  auto in = fmt::file("test-file", file::RDONLY);
+  EXPECT_READ(in, "x");
+}
+
 TEST(file_test, default_ctor) {
   file f;
   EXPECT_EQ(-1, f.descriptor());
@@ -540,13 +548,4 @@ TEST(file_test, fdopen) {
   int read_fd = read_end.descriptor();
   EXPECT_EQ(read_fd, FMT_POSIX(fileno(read_end.fdopen("r").get())));
 }
-
-#  ifdef FMT_LOCALE
-TEST(locale_test, strtod) {
-  fmt::locale loc;
-  const char *start = "4.2", *ptr = start;
-  EXPECT_EQ(4.2, loc.strtod(ptr));
-  EXPECT_EQ(start + 3, ptr);
-}
-#  endif
 #endif  // FMT_USE_FCNTL

test/ostream-test.cc

@@ -23,6 +23,7 @@ template <> struct formatter<test> : formatter<int> {
 
 #include <sstream>
 
+#include "fmt/compile.h"
 #include "fmt/ostream.h"
 #include "fmt/ranges.h"
 #include "gmock/gmock.h"
@@ -69,16 +70,16 @@ TEST(ostream_test, format_specs) {
   EXPECT_EQ("  def", fmt::format("{0:>5}", test_string("def")));
   EXPECT_EQ(" def ", fmt::format("{0:^5}", test_string("def")));
   EXPECT_EQ("def**", fmt::format("{0:*<5}", test_string("def")));
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:+}"), test_string()), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), test_string()),
-                   "format specifier requires numeric argument");
+                   format_error, "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:-}"), test_string()), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), test_string()),
-                   "format specifier requires numeric argument");
+                   format_error, "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0: }"), test_string()), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), test_string()),
-                   "format specifier requires numeric argument");
+                   format_error, "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:#}"), test_string()), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), test_string()),
-                   "format specifier requires numeric argument");
+                   format_error, "format specifier requires numeric argument");
-  EXPECT_THROW_MSG(fmt::format(runtime("{0:05}"), test_string()), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), test_string()),
-                   "format specifier requires numeric argument");
+                   format_error, "format specifier requires numeric argument");
   EXPECT_EQ("test         ", fmt::format("{0:13}", test_string("test")));
   EXPECT_EQ("test         ", fmt::format("{0:{1}}", test_string("test"), 13));
   EXPECT_EQ("te", fmt::format("{0:.2}", test_string("test")));
@@ -115,12 +116,12 @@ TEST(ostream_test, write_to_ostream_max_size) {
   struct test_buffer final : fmt::detail::buffer<char> {
     explicit test_buffer(size_t size)
         : fmt::detail::buffer<char>(nullptr, size, size) {}
-    void grow(size_t) {}
+    void grow(size_t) override {}
   } buffer(max_size);
 
   struct mock_streambuf : std::streambuf {
     MOCK_METHOD2(xsputn, std::streamsize(const void* s, std::streamsize n));
-    std::streamsize xsputn(const char* s, std::streamsize n) {
+    std::streamsize xsputn(const char* s, std::streamsize n) override {
       const void* v = s;
       return xsputn(v, n);
     }
@@ -257,7 +258,8 @@ std::ostream& operator<<(std::ostream& os, streamable_and_convertible_to_bool) {
 }
 
 TEST(ostream_test, format_convertible_to_bool) {
-  EXPECT_EQ("foo", fmt::format("{}", streamable_and_convertible_to_bool()));
+  // operator<< is intentionally not used because of potential ODR violations.
+  EXPECT_EQ(fmt::format("{}", streamable_and_convertible_to_bool()), "true");
 }
 
 struct copyfmt_test {};
@@ -280,3 +282,20 @@ TEST(ostream_test, range) {
   auto strs = std::vector<test_string>{test_string("foo"), test_string("bar")};
   EXPECT_EQ("[foo, bar]", fmt::format("{}", strs));
 }
+
+struct abstract {
+  virtual ~abstract() = default;
+  virtual void f() = 0;
+  friend std::ostream& operator<<(std::ostream& os, const abstract&) {
+    return os;
+  }
+};
+
+void format_abstract_compiles(const abstract& a) {
+  fmt::format(FMT_COMPILE("{}"), a);
+}
+
+TEST(ostream_test, is_formattable) {
+  EXPECT_TRUE(fmt::is_formattable<std::string>());
+  EXPECT_TRUE(fmt::is_formattable<fmt::detail::std_string_view<char>>());
+}

test/posix-mock-test.cc

@@ -467,9 +467,6 @@ struct locale_mock {
   MOCK_METHOD3(newlocale, locale_type(int category_mask, const char* locale,
                                       locale_type base));
   MOCK_METHOD1(freelocale, void(locale_type locale));
-
-  MOCK_METHOD3(strtod_l,
-               double(const char* nptr, char** endptr, locale_type locale));
 } * locale_mock::instance;
 
 #  ifdef _MSC_VER
@@ -487,10 +484,6 @@ _locale_t _create_locale(int category, const char* locale) {
 void _free_locale(_locale_t locale) {
   locale_mock::instance->freelocale(locale);
 }
-
-double _strtod_l(const char* nptr, char** endptr, _locale_t locale) {
-  return locale_mock::instance->strtod_l(nptr, endptr, locale);
-}
 #    ifdef __clang__
 #      pragma clang diagnostic pop
 #    endif
@@ -516,11 +509,6 @@ FreeLocaleResult freelocale(locale_type locale) FMT_LOCALE_THROW {
   return FreeLocaleResult();
 }
 
-double strtod_l(const char* nptr, char** endptr,
-                locale_type locale) FMT_LOCALE_THROW {
-  return locale_mock::instance->strtod_l(nptr, endptr, locale);
-}
-
 #  undef FMT_LOCALE_THROW
 
 #  ifndef _WIN32
@@ -549,18 +537,4 @@ TEST(locale_test, locale) {
   EXPECT_EQ(impl, loc.get());
 }
 
-TEST(locale_test, strtod) {
-  scoped_mock<locale_mock> mock;
-  EXPECT_CALL(mock, newlocale(_, _, _))
-      .WillOnce(Return(reinterpret_cast<locale_type>(42)));
-  EXPECT_CALL(mock, freelocale(_));
-  fmt::locale loc;
-  const char* str = "4.2";
-  char end = 'x';
-  EXPECT_CALL(mock, strtod_l(str, _, loc.get()))
-      .WillOnce(testing::DoAll(testing::SetArgPointee<1>(&end), Return(777)));
-  EXPECT_EQ(777, loc.strtod(str));
-  EXPECT_EQ(&end, str);
-}
-
 #endif  // FMT_LOCALE

test/printf-test.cc

@@ -481,12 +481,6 @@ TEST(printf_test, string) {
   EXPECT_PRINTF(L"    (null)", L"%10s", null_wstr);
 }
 
-TEST(printf_test, uchar_string) {
-  unsigned char str[] = "test";
-  unsigned char* pstr = str;
-  EXPECT_EQ("test", fmt::sprintf("%s", pstr));
-}
-
 TEST(printf_test, pointer) {
   int n;
   void* p = &n;

test/ranges-odr-test.cc

@@ -0,0 +1,17 @@
+// Formatting library for C++ - the core API
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <vector>
+
+#include "fmt/ranges.h"
+#include "gtest/gtest.h"
+
+// call fmt::format from another translation unit to test ODR
+TEST(ranges_odr_test, format_vector) {
+  auto v = std::vector<int>{1, 2, 3, 5, 7, 11};
+  EXPECT_EQ(fmt::format("{}", v), "[1, 2, 3, 5, 7, 11]");
+}

test/ranges-test.cc

@@ -55,7 +55,12 @@ TEST(ranges_test, format_vector2) {
 
 TEST(ranges_test, format_map) {
   auto m = std::map<std::string, int>{{"one", 1}, {"two", 2}};
-  EXPECT_EQ(fmt::format("{}", m), "[(\"one\", 1), (\"two\", 2)]");
+  EXPECT_EQ(fmt::format("{}", m), "{\"one\": 1, \"two\": 2}");
+}
+
+TEST(ranges_test, format_set) {
+  EXPECT_EQ(fmt::format("{}", std::set<std::string>{"one", "two"}),
+            "{\"one\", \"two\"}");
 }
 
 TEST(ranges_test, format_pair) {
@@ -190,7 +195,14 @@ TEST(ranges_test, range) {
   EXPECT_EQ(fmt::format("{}", z), "[0, 0, 0]");
 }
 
-#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
+enum test_enum { foo };
+
+TEST(ranges_test, enum_range) {
+  auto v = std::vector<test_enum>{test_enum::foo};
+  EXPECT_EQ(fmt::format("{}", v), "[0]");
+}
+
+#if !FMT_MSC_VER
 struct unformattable {};
 
 TEST(ranges_test, unformattable_range) {
@@ -217,6 +229,21 @@ TEST(ranges_test, join_tuple) {
   // Single element tuple.
   auto t4 = std::tuple<float>(4.0f);
   EXPECT_EQ(fmt::format("{}", fmt::join(t4, "/")), "4");
+
+#  if FMT_TUPLE_JOIN_SPECIFIERS
+  // Specs applied to each element.
+  auto t5 = std::tuple<int, int, long>(-3, 100, 1);
+  EXPECT_EQ(fmt::format("{:+03}", fmt::join(t5, ", ")), "-03, +100, +01");
+
+  auto t6 = std::tuple<float, double, long double>(3, 3.14, 3.1415);
+  EXPECT_EQ(fmt::format("{:5.5f}", fmt::join(t6, ", ")),
+            "3.00000, 3.14000, 3.14150");
+
+  // Testing lvalue tuple args.
+  int y = -1;
+  auto t7 = std::tuple<int, int&, const int&>(3, y, y);
+  EXPECT_EQ(fmt::format("{:03}", fmt::join(t7, ", ")), "003, -01, -01");
+#  endif
 }
 
 TEST(ranges_test, join_initializer_list) {
@@ -236,6 +263,36 @@ struct zstring {
   zstring_sentinel end() const { return {}; }
 };
 
+#  ifdef __cpp_lib_ranges
+struct cpp20_only_range {
+  struct iterator {
+    int val = 0;
+
+    using value_type = int;
+    using difference_type = std::ptrdiff_t;
+    using iterator_concept = std::input_iterator_tag;
+
+    iterator() = default;
+    iterator(int i) : val(i) {}
+    int operator*() const { return val; }
+    iterator& operator++() {
+      ++val;
+      return *this;
+    }
+    void operator++(int) { ++*this; }
+    bool operator==(const iterator& rhs) const { return val == rhs.val; }
+  };
+
+  int lo;
+  int hi;
+
+  iterator begin() const { return iterator(lo); }
+  iterator end() const { return iterator(hi); }
+};
+
+static_assert(std::input_iterator<cpp20_only_range::iterator>);
+#  endif
+
 TEST(ranges_test, join_sentinel) {
   auto hello = zstring{"hello"};
   EXPECT_EQ(fmt::format("{}", hello), "['h', 'e', 'l', 'l', 'o']");
@@ -260,5 +317,47 @@ TEST(ranges_test, join_range) {
 
   const auto z = std::vector<int>(3u, 0);
   EXPECT_EQ(fmt::format("{}", fmt::join(z, ",")), "0,0,0");
+
+#  ifdef __cpp_lib_ranges
+  EXPECT_EQ(fmt::format("{}", cpp20_only_range{.lo = 0, .hi = 5}),
+            "[0, 1, 2, 3, 4]");
+  EXPECT_EQ(
+      fmt::format("{}", fmt::join(cpp20_only_range{.lo = 0, .hi = 5}, ",")),
+      "0,1,2,3,4");
+#  endif
 }
 #endif  // FMT_RANGES_TEST_ENABLE_JOIN
+
+TEST(ranges_test, is_printable) {
+  using fmt::detail::is_printable;
+  EXPECT_TRUE(is_printable(0x0323));
+  EXPECT_FALSE(is_printable(0x0378));
+  EXPECT_FALSE(is_printable(0x110000));
+}
+
+TEST(ranges_test, escape_string) {
+  using vec = std::vector<std::string>;
+  EXPECT_EQ(fmt::format("{}", vec{"\n\r\t\"\\"}), "[\"\\n\\r\\t\\\"\\\\\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"\x07"}), "[\"\\x07\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"\x7f"}), "[\"\\x7f\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"n\xcc\x83"}), "[\"n\xcc\x83\"]");
+
+  if (fmt::detail::is_utf8()) {
+    EXPECT_EQ(fmt::format("{}", vec{"\xcd\xb8"}), "[\"\\u0378\"]");
+    // Unassigned Unicode code points.
+    EXPECT_EQ(fmt::format("{}", vec{"\xf0\xaa\x9b\x9e"}), "[\"\\U0002a6de\"]");
+    EXPECT_EQ(fmt::format("{}", vec{"\xf4\x8f\xbf\xc0"}),
+              "[\"\\xf4\\x8f\\xbf\\xc0\"]");
+  }
+}
+
+#ifdef FMT_USE_STRING_VIEW
+struct convertible_to_string_view {
+  operator std::string_view() const { return "foo"; }
+};
+
+TEST(ranges_test, escape_convertible_to_string_view) {
+  EXPECT_EQ(fmt::format("{}", std::vector<convertible_to_string_view>(1)),
+            "[\"foo\"]");
+}
+#endif  // FMT_USE_STRING_VIEW

test/std-format-test.cc

@@ -1,161 +0,0 @@
-#include <format>
-
-#include "gtest/gtest.h"
-
-TEST(std_format_test, escaping) {
-  using namespace std;
-  string s = format("{0}-{{", 8);  // s == "8-{"
-  EXPECT_EQ(s, "8-{");
-}
-
-TEST(std_format_test, indexing) {
-  using namespace std;
-  string s0 = format("{} to {}", "a", "b");    // OK: automatic indexing
-  string s1 = format("{1} to {0}", "a", "b");  // OK: manual indexing
-  EXPECT_EQ(s0, "a to b");
-  EXPECT_EQ(s1, "b to a");
-  // Error: mixing automatic and manual indexing
-  EXPECT_THROW(string s2 = format("{0} to {}", "a", "b"), std::format_error);
-  // Error: mixing automatic and manual indexing
-  EXPECT_THROW(string s3 = format("{} to {1}", "a", "b"), std::format_error);
-}
-
-TEST(std_format_test, alignment) {
-  using namespace std;
-  char c = 120;
-  string s0 = format("{:6}", 42);     // s0 == "    42"
-  string s1 = format("{:6}", 'x');    // s1 == "x     "
-  string s2 = format("{:*<6}", 'x');  // s2 == "x*****"
-  string s3 = format("{:*>6}", 'x');  // s3 == "*****x"
-  string s4 = format("{:*^6}", 'x');  // s4 == "**x***"
-  // Error: '=' with charT and no integer presentation type
-  EXPECT_THROW(string s5 = format("{:=6}", 'x'), std::format_error);
-  string s6 = format("{:6d}", c);    // s6 == "   120"
-  string s7 = format("{:6}", true);  // s9 == "true  "
-  EXPECT_EQ(s0, "    42");
-  EXPECT_EQ(s1, "x     ");
-  EXPECT_EQ(s2, "x*****");
-  EXPECT_EQ(s3, "*****x");
-  EXPECT_EQ(s4, "**x***");
-  EXPECT_EQ(s6, "   120");
-  EXPECT_EQ(s7, "true  ");
-}
-
-TEST(std_format_test, float) {
-  using namespace std;
-  double inf = numeric_limits<double>::infinity();
-  double nan = numeric_limits<double>::quiet_NaN();
-  string s0 = format("{0:} {0:+} {0:-} {0: }", 1);   // s0 == "1 +1 1  1"
-  string s1 = format("{0:} {0:+} {0:-} {0: }", -1);  // s1 == "-1 -1 -1 -1"
-  string s2 =
-      format("{0:} {0:+} {0:-} {0: }", inf);  // s2 == "inf +inf inf  inf"
-  string s3 =
-      format("{0:} {0:+} {0:-} {0: }", nan);  // s3 == "nan +nan nan  nan"
-  EXPECT_EQ(s0, "1 +1 1  1");
-  EXPECT_EQ(s1, "-1 -1 -1 -1");
-  EXPECT_EQ(s2, "inf +inf inf  inf");
-  EXPECT_EQ(s3, "nan +nan nan  nan");
-}
-
-TEST(std_format_test, int) {
-  using namespace std;
-  string s0 = format("{}", 42);                       // s0 == "42"
-  string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);  // s1 == "101010 42 52 2a"
-  string s2 = format("{0:#x} {0:#X}", 42);            // s2 == "0x2a 0X2A"
-  string s3 = format("{:L}", 1234);  // s3 == "1234" (depends on the locale)
-  EXPECT_EQ(s0, "42");
-  EXPECT_EQ(s1, "101010 42 52 2a");
-  EXPECT_EQ(s2, "0x2a 0X2A");
-  EXPECT_EQ(s3, "1234");
-}
-
-#include <format>
-
-enum color { red, green, blue };
-
-const char* color_names[] = {"red", "green", "blue"};
-
-template <> struct std::formatter<color> : std::formatter<const char*> {
-  auto format(color c, format_context& ctx) {
-    return formatter<const char*>::format(color_names[c], ctx);
-  }
-};
-
-struct err {};
-
-TEST(std_format_test, formatter) {
-  std::string s0 = std::format("{}", 42);  // OK: library-provided formatter
-  // std::string s1 = std::format("{}", L"foo"); // Ill-formed: disabled
-  // formatter
-  std::string s2 = std::format("{}", red);  // OK: user-provided formatter
-  // std::string s3 = std::format("{}", err{});  // Ill-formed: disabled
-  // formatter
-  EXPECT_EQ(s0, "42");
-  EXPECT_EQ(s2, "red");
-}
-
-struct S {
-  int value;
-};
-
-template <> struct std::formatter<S> {
-  size_t width_arg_id = 0;
-
-  // Parses a width argument id in the format { <digit> }.
-  constexpr auto parse(format_parse_context& ctx) {
-    constexpr auto is_ascii_digit = [](const char c) {
-      return c >= '0' && c <= '9';
-    };
-
-    auto iter = ctx.begin();
-    // auto get_char = [&]() { return iter != ctx.end() ? *iter : 0; };
-    auto get_char = [&]() { return iter != ctx.end() ? *iter : '\0'; };
-    if (get_char() != '{') return iter;
-    ++iter;
-    char c = get_char();
-    if (!is_ascii_digit(c) || (++iter, get_char()) != '}')
-      throw format_error("invalid format");
-    width_arg_id = fmt::detail::to_unsigned(c - '0');
-    ctx.check_arg_id(width_arg_id);
-    return ++iter;
-  }
-
-  // Formats S with width given by the argument width_arg_id.
-  auto format(S s, format_context& ctx) {
-    int width = visit_format_arg(
-        [](auto value) -> int {
-          using type = decltype(value);
-          if constexpr (!is_integral_v<type> || is_same_v<type, bool>)
-            throw format_error("width is not integral");
-          // else if (value < 0 || value > numeric_limits<int>::max())
-          else if (fmt::detail::is_negative(value) ||
-                   value > numeric_limits<int>::max())
-            throw format_error("invalid width");
-          else
-            return static_cast<int>(value);
-        },
-        ctx.arg(width_arg_id));
-    return format_to(ctx.out(), "{0:{1}}", s.value, width);
-  }
-};
-
-TEST(std_format_test, parsing) {
-  std::string s = std::format("{0:{1}}", S{42}, 10);  // s == "        42"
-  EXPECT_EQ(s, "        42");
-}
-
-#if FMT_USE_INT128
-template <> struct std::formatter<__int128_t> : std::formatter<long long> {
-  auto format(__int128_t n, format_context& ctx) {
-    // Format as a long long since we only want to check if it is possible to
-    // specialize formatter for __int128_t.
-    return formatter<long long>::format(static_cast<long long>(n), ctx);
-  }
-};
-
-TEST(std_format_test, int128) {
-  __int128_t n = 42;
-  auto s = std::format("{}", n);
-  EXPECT_EQ(s, "42");
-}
-#endif  // FMT_USE_INT128

test/test-main.cc

@@ -35,6 +35,7 @@ int main(int argc, char** argv) {
   _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
   try {
     testing::InitGoogleTest(&argc, argv);
+    testing::FLAGS_gtest_death_test_style = "threadsafe";
     return RUN_ALL_TESTS();
   } catch (...) {
     // Catch all exceptions to make Coverity happy.

test/unicode-test.cc

@@ -18,7 +18,7 @@ using testing::Contains;
 TEST(unicode_test, is_utf8) { EXPECT_TRUE(fmt::detail::is_utf8()); }
 
 TEST(unicode_test, legacy_locale) {
-  auto loc = get_locale("ru_RU.CP1251", "Russian.1251");
+  auto loc = get_locale("ru_RU.CP1251", "Russian_Russia.1251");
   if (loc == std::locale::classic()) return;
 
   auto s = std::string();

test/util.h

@@ -10,7 +10,11 @@
 #include <locale>
 #include <string>
 
-#include "fmt/os.h"
+#ifdef FMT_MODULE_TEST
+import fmt;
+#else
+#  include "fmt/os.h"
+#endif  // FMT_MODULE_TEST
 
 #ifdef _MSC_VER
 #  define FMT_VSNPRINTF vsprintf_s
@@ -34,7 +38,7 @@ fmt::buffered_file open_buffered_file(FILE** fp = nullptr);
 inline FILE* safe_fopen(const char* filename, const char* mode) {
 #if defined(_WIN32) && !defined(__MINGW32__)
   // Fix MSVC warning about "unsafe" fopen.
-  FILE* f = 0;
+  FILE* f = nullptr;
   errno = fopen_s(&f, filename, mode);
   return f;
 #else

test/xchar-test.cc

@@ -8,14 +8,18 @@
 #include "fmt/xchar.h"
 
 #include <complex>
+#include <cwchar>
+#include <vector>
 
 #include "fmt/chrono.h"
 #include "fmt/color.h"
 #include "fmt/ostream.h"
 #include "fmt/ranges.h"
-#include "gtest/gtest.h"
+#include "gtest-extra.h"  // Contains
+#include "util.h"         // get_locale
 
 using fmt::detail::max_value;
+using testing::Contains;
 
 namespace test_ns {
 template <typename Char> class test_string {
@@ -87,6 +91,10 @@ TEST(xchar_test, format) {
   EXPECT_EQ(L"abc1", fmt::format(L"{}c{}", L"ab", 1));
 }
 
+TEST(xchar_test, is_formattable) {
+  static_assert(!fmt::is_formattable<const wchar_t*>::value, "");
+}
+
 TEST(xchar_test, compile_time_string) {
 #if defined(FMT_USE_STRING_VIEW) && __cplusplus >= 201703L
   EXPECT_EQ(L"42", fmt::format(FMT_STRING(std::wstring_view(L"{}")), 42));
@@ -257,6 +265,55 @@ TEST(xchar_test, chrono) {
   EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
             "The date is 2016-04-25 11:22:33.");
   EXPECT_EQ(L"42s", fmt::format(L"{}", std::chrono::seconds(42)));
+  EXPECT_EQ(fmt::format(L"{:%F}", tm), L"2016-04-25");
+  EXPECT_EQ(fmt::format(L"{:%T}", tm), L"11:22:33");
+}
+
+std::wstring system_wcsftime(const std::wstring& format, const std::tm* timeptr,
+                             std::locale* locptr = nullptr) {
+  auto loc = locptr ? *locptr : std::locale::classic();
+  auto& facet = std::use_facet<std::time_put<wchar_t>>(loc);
+  std::wostringstream os;
+  os.imbue(loc);
+  facet.put(os, os, L' ', timeptr, format.c_str(),
+            format.c_str() + format.size());
+#ifdef _WIN32
+  // Workaround a bug in older versions of Universal CRT.
+  auto str = os.str();
+  if (str == L"-0000") str = L"+0000";
+  return str;
+#else
+  return os.str();
+#endif
+}
+
+TEST(chrono_test, time_point) {
+  auto t1 = std::chrono::system_clock::now();
+
+  std::vector<std::wstring> spec_list = {
+      L"%%",  L"%n",  L"%t",  L"%Y",  L"%EY", L"%y",  L"%Oy", L"%Ey", L"%C",
+      L"%EC", L"%G",  L"%g",  L"%b",  L"%h",  L"%B",  L"%m",  L"%Om", L"%U",
+      L"%OU", L"%W",  L"%OW", L"%V",  L"%OV", L"%j",  L"%d",  L"%Od", L"%e",
+      L"%Oe", L"%a",  L"%A",  L"%w",  L"%Ow", L"%u",  L"%Ou", L"%H",  L"%OH",
+      L"%I",  L"%OI", L"%M",  L"%OM", L"%S",  L"%OS", L"%x",  L"%Ex", L"%X",
+      L"%EX", L"%D",  L"%F",  L"%R",  L"%T",  L"%p",  L"%z",  L"%Z"};
+  spec_list.push_back(L"%Y-%m-%d %H:%M:%S");
+#ifndef _WIN32
+  // Disabled on Windows, because these formats is not consistent among
+  // platforms.
+  spec_list.insert(spec_list.end(), {L"%c", L"%Ec", L"%r"});
+#endif
+
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::localtime(&t);
+
+    auto sys_output = system_wcsftime(spec, &tm);
+
+    auto fmt_spec = fmt::format(L"{{:{}}}", spec);
+    EXPECT_EQ(sys_output, fmt::format(fmt_spec, t1));
+    EXPECT_EQ(sys_output, fmt::format(fmt_spec, tm));
+  }
 }
 
 TEST(xchar_test, color) {
@@ -301,10 +358,12 @@ template <typename Char> struct small_grouping : std::numpunct<Char> {
   Char do_thousands_sep() const override { return ','; }
 };
 
-TEST(locale_test, double_decimal_point) {
+TEST(locale_test, localized_double) {
   auto loc = std::locale(std::locale(), new numpunct<char>());
   EXPECT_EQ("1?23", fmt::format(loc, "{:L}", 1.23));
   EXPECT_EQ("1?230000", fmt::format(loc, "{:Lf}", 1.23));
+  EXPECT_EQ("1~234?5", fmt::format(loc, "{:L}", 1234.5));
+  EXPECT_EQ("12~000", fmt::format(loc, "{:L}", 12000.0));
 }
 
 TEST(locale_test, format) {
@@ -403,7 +462,7 @@ template <class charT> struct formatter<std::complex<double>, charT> {
         specs_.precision, specs_.precision_ref, ctx);
     auto specs = std::string();
     if (specs_.precision > 0) specs = fmt::format(".{}", specs_.precision);
-    if (specs_.type) specs += specs_.type;
+    if (specs_.type == presentation_type::fixed_lower) specs += 'f';
     auto real = fmt::format(ctx.locale().template get<std::locale>(),
                             fmt::runtime("{:" + specs + "}"), c.real());
     auto imag = fmt::format(ctx.locale().template get<std::locale>(),
@@ -424,4 +483,20 @@ TEST(locale_test, complex) {
   EXPECT_EQ(fmt::format("{:8}", std::complex<double>(1, 2)), "  (1+2i)");
 }
 
+TEST(locale_test, chrono_weekday) {
+  auto loc = get_locale("ru_RU.UTF-8", "Russian_Russia.1251");
+  auto loc_old = std::locale::global(loc);
+  auto mon = fmt::weekday(1);
+  EXPECT_EQ(fmt::format(L"{}", mon), L"Mon");
+  if (loc != std::locale::classic()) {
+    // {L"\x43F\x43D", L"\x41F\x43D", L"\x43F\x43D\x434", L"\x41F\x43D\x434"}
+    // {L"пн", L"Пн", L"пнд", L"Пнд"}
+    EXPECT_THAT(
+        (std::vector<std::wstring>{L"\x43F\x43D", L"\x41F\x43D",
+                                   L"\x43F\x43D\x434", L"\x41F\x43D\x434"}),
+        Contains(fmt::format(loc, L"{:L}", mon)));
+  }
+  std::locale::global(loc_old);
+}
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR