Update version

Signed-off-by: Vladislav Shchapov <vladislav@shchapov.ru>

.github/pull_request_template.md

@@ -1,6 +1,7 @@
 <!--
 Please read the contribution guidelines before submitting a pull request:
 https://github.com/fmtlib/fmt/blob/master/CONTRIBUTING.md.
-By submitting this pull request, you agree that your contributions are licensed
-under the {fmt} license, and agree to future changes to the licensing.
+By submitting this pull request, you agree to license your contribution(s)
+under the terms outlined in LICENSE.rst and represent that you have the right
+to do so.
 -->

.github/workflows/cifuzz.yml

@@ -0,0 +1,30 @@
+name: CIFuzz
+on: [pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  Fuzzing:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Build Fuzzers
+      id: build
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'fmt'
+        dry-run: false
+        language: c++
+    - name: Run Fuzzers
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'fmt'
+        fuzz-seconds: 300
+        dry-run: false
+        language: c++
+    - name: Upload Crash
+      uses: actions/upload-artifact@v3
+      if: failure() && steps.build.outcome == 'success'
+      with:
+        name: artifacts
+        path: ./out/artifacts

.github/workflows/doc.yml

@@ -11,7 +11,15 @@ jobs:
     runs-on: ubuntu-20.04
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+
+    - name: Add ubuntu mirrors
+      run: |
+        # Github Actions caching proxy is at times unreliable
+        # see https://github.com/actions/runner-images/issues/7048
+        printf 'http://azure.archive.ubuntu.com/ubuntu\tpriority:1\n' | sudo tee /etc/apt/mirrors.txt
+        curl http://mirrors.ubuntu.com/mirrors.txt | sudo tee --append /etc/apt/mirrors.txt
+        sudo sed -i 's~http://azure.archive.ubuntu.com/ubuntu/~mirror+file:/etc/apt/mirrors.txt~' /etc/apt/sources.list
 
     - name: Create Build Environment
       run: |

.github/workflows/linux.yml

@@ -7,66 +7,83 @@ permissions:
 
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         cxx: [g++-4.8, g++-10, clang++-9]
         build_type: [Debug, Release]
         std: [11]
-        os: [ubuntu-18.04]
         include:
           - cxx: g++-4.8
             install: sudo apt install g++-4.8
-            os: ubuntu-18.04
           - cxx: g++-8
             build_type: Debug
             std: 14
             install: sudo apt install g++-8
-            os: ubuntu-18.04
           - cxx: g++-8
             build_type: Debug
             std: 17
             install: sudo apt install g++-8
-            os: ubuntu-18.04
+          - cxx: g++-9
+            build_type: Debug
+            std: 17
           - cxx: g++-10
             build_type: Debug
             std: 17
-            os: ubuntu-18.04
           - cxx: g++-11
             build_type: Debug
             std: 20
-            os: ubuntu-20.04
             install: sudo apt install g++-11
           - cxx: clang++-8
             build_type: Debug
             std: 17
             cxxflags: -stdlib=libc++
-            os: ubuntu-18.04
             install: sudo apt install clang-8 libc++-8-dev libc++abi-8-dev
+          - cxx: clang++-9
+            install: sudo apt install clang-9
           - cxx: clang++-9
             build_type: Debug
             fuzz: -DFMT_FUZZ=ON -DFMT_FUZZ_LINKMAIN=ON
             std: 17
-            os: ubuntu-18.04
+            install: sudo apt install clang-9
           - cxx: clang++-11
             build_type: Debug
             std: 20
-            os: ubuntu-20.04
           - cxx: clang++-11
             build_type: Debug
             std: 20
             cxxflags: -stdlib=libc++
-            os: ubuntu-20.04
             install: sudo apt install libc++-11-dev libc++abi-11-dev
           - shared: -DBUILD_SHARED_LIBS=ON
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+
+    - name: Set timezone
+      run: sudo timedatectl set-timezone 'Asia/Yekaterinburg'
+
+    - name: Add repositories for older GCC
+      run: |
+        # Below two repos provide GCC 4.8, 5.5 and 6.4
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic main'
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic universe'
+        # Below two repos additionally update GCC 6 to 6.5
+        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates main'
+        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates universe'
+      if: ${{ matrix.cxx == 'g++-4.8' }}
+
+    - name: Add ubuntu mirrors
+      run: |
+        # Github Actions caching proxy is at times unreliable
+        # see https://github.com/actions/runner-images/issues/7048
+        printf 'http://azure.archive.ubuntu.com/ubuntu\tpriority:1\n' | sudo tee /etc/apt/mirrors.txt
+        curl http://mirrors.ubuntu.com/mirrors.txt | sudo tee --append /etc/apt/mirrors.txt
+        sudo sed -i 's~http://azure.archive.ubuntu.com/ubuntu/~mirror+file:/etc/apt/mirrors.txt~' /etc/apt/sources.list
 
     - name: Create Build Environment
       run: |
-        ${{matrix.install}}
         sudo apt update
+        ${{matrix.install}}
         sudo apt install locales-all
         cmake -E make_directory ${{runner.workspace}}/build
 

.github/workflows/macos.yml

@@ -7,15 +7,19 @@ permissions:
 
 jobs:
   build:
-    runs-on: macos-10.15
+    runs-on: macos-11
     strategy:
       matrix:
         build_type: [Debug, Release]
+        std: [11, 17]
         include:
           - shared: -DBUILD_SHARED_LIBS=ON
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+
+    - name: Set timezone
+      run: sudo systemsetup -settimezone 'Asia/Yekaterinburg'
 
     - name: Create Build Environment
       run: cmake -E make_directory ${{runner.workspace}}/build
@@ -24,6 +28,7 @@ jobs:
       working-directory: ${{runner.workspace}}/build
       run: |
         cmake -DCMAKE_BUILD_TYPE=${{matrix.build_type}} ${{matrix.shared}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
               -DCMAKE_CXX_VISIBILITY_PRESET=hidden -DCMAKE_VISIBILITY_INLINES_HIDDEN=ON \
               -DFMT_DOC=OFF -DFMT_PEDANTIC=ON -DFMT_WERROR=ON $GITHUB_WORKSPACE
 

.github/workflows/windows.yml

@@ -41,7 +41,10 @@ jobs:
             standard: 20
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+
+    - name: Set timezone
+      run: tzutil /s "Ekaterinburg Standard Time"
 
     - name: Create Build Environment
       run: cmake -E make_directory ${{runner.workspace}}/build
@@ -75,14 +78,17 @@ jobs:
         shell: msys2 {0}
     strategy:
       matrix:
-        sys: [ mingw64, mingw32, ucrt64 ]
+        sys: [ mingw64, ucrt64 ]
     steps:
+    - name: Set timezone
+      run: tzutil /s "Ekaterinburg Standard Time"
+      shell: cmd
     - uses: msys2/setup-msys2@v2
       with:
         release: false
         msystem: ${{matrix.sys}}
         pacboy: cc:p cmake:p ninja:p lld:p
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Configure
       run: cmake -B ../build -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Debug
       env: { LDFLAGS: -fuse-ld=lld }
@@ -90,3 +96,5 @@ jobs:
       run: cmake --build ../build
     - name: Test
       run: ctest -j `nproc` --test-dir ../build
+      env:
+        CTEST_OUTPUT_ON_FAILURE: True

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.18)
+cmake_minimum_required(VERSION 3.8...3.26)
 
 # Fallback for using newer policies on CMake <3.12.
 if(${CMAKE_VERSION} VERSION_LESS 3.12)
@@ -24,15 +24,86 @@ function(join result_var)
   set(${result_var} "${result}" PARENT_SCOPE)
 endfunction()
 
+# DEPRECATED! Should be merged into add_module_library.
 function(enable_module target)
   if (MSVC)
     set(BMI ${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc)
     target_compile_options(${target}
       PRIVATE /interface /ifcOutput ${BMI}
       INTERFACE /reference fmt=${BMI})
+    set_target_properties(${target} PROPERTIES ADDITIONAL_CLEAN_FILES ${BMI})
+    set_source_files_properties(${BMI} PROPERTIES GENERATED ON)
   endif ()
-  set_target_properties(${target} PROPERTIES ADDITIONAL_CLEAN_FILES ${BMI})
-  set_source_files_properties(${BMI} PROPERTIES GENERATED ON)
+endfunction()
+
+# Adds a library compiled with C++20 module support.
+# `enabled` is a CMake variables that specifies if modules are enabled.
+# If modules are disabled `add_module_library` falls back to creating a
+# non-modular library.
+#
+# Usage:
+#   add_module_library(<name> [sources...] FALLBACK [sources...] [IF enabled])
+function(add_module_library name)
+  cmake_parse_arguments(AML "" "IF" "FALLBACK" ${ARGN})
+  set(sources ${AML_UNPARSED_ARGUMENTS})
+
+  add_library(${name})
+  set_target_properties(${name} PROPERTIES LINKER_LANGUAGE CXX)
+
+  if (NOT ${${AML_IF}})
+    # Create a non-modular library.
+    target_sources(${name} PRIVATE ${AML_FALLBACK})
+    return()
+  endif ()
+
+  # Modules require C++20.
+  target_compile_features(${name} PUBLIC cxx_std_20)
+  if (CMAKE_COMPILER_IS_GNUCXX)
+    target_compile_options(${name} PUBLIC -fmodules-ts)
+  endif ()
+
+  # `std` is affected by CMake options and may be higher than C++20.
+  get_target_property(std ${name} CXX_STANDARD)
+
+  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    set(pcms)
+    foreach (src ${sources})
+      get_filename_component(pcm ${src} NAME_WE)
+      set(pcm ${pcm}.pcm)
+
+      # Propagate -fmodule-file=*.pcm to targets that link with this library.
+      target_compile_options(
+        ${name} PUBLIC -fmodule-file=${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+
+      # Use an absolute path to prevent target_link_libraries prepending -l
+      # to it.
+      set(pcms ${pcms} ${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+      add_custom_command(
+        OUTPUT ${pcm}
+        COMMAND ${CMAKE_CXX_COMPILER}
+                -std=c++${std} -x c++-module --precompile -c
+                -o ${pcm} ${CMAKE_CURRENT_SOURCE_DIR}/${src}
+                "-I$<JOIN:$<TARGET_PROPERTY:${name},INCLUDE_DIRECTORIES>,;-I>"
+        # Required by the -I generator expression above.
+        COMMAND_EXPAND_LISTS
+        DEPENDS ${src})
+    endforeach ()
+
+    # Add .pcm files as sources to make sure they are built before the library.
+    set(sources)
+    foreach (pcm ${pcms})
+      get_filename_component(pcm_we ${pcm} NAME_WE)
+      set(obj ${pcm_we}.o)
+      # Use an absolute path to prevent target_link_libraries prepending -l.
+      set(sources ${sources} ${pcm} ${CMAKE_CURRENT_BINARY_DIR}/${obj})
+      add_custom_command(
+        OUTPUT ${obj}
+        COMMAND ${CMAKE_CXX_COMPILER} $<TARGET_PROPERTY:${name},COMPILE_OPTIONS>
+                -c -o ${obj} ${pcm}
+        DEPENDS ${pcm})
+    endforeach ()
+  endif ()
+  target_sources(${name} PRIVATE ${sources})
 endfunction()
 
 include(CMakeParseArguments)
@@ -75,7 +146,7 @@ option(FMT_WERROR "Halt the compilation with an error on compiler warnings."
 
 # Options that control generation of various targets.
 option(FMT_DOC "Generate the doc target." ${FMT_MASTER_PROJECT})
-option(FMT_INSTALL "Generate the install target." ${FMT_MASTER_PROJECT})
+option(FMT_INSTALL "Generate the install target." ON)
 option(FMT_TEST "Generate the test target." ${FMT_MASTER_PROJECT})
 option(FMT_FUZZ "Generate the fuzz target." OFF)
 option(FMT_CUDA_TEST "Generate the cuda-test target." OFF)
@@ -83,16 +154,6 @@ 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 OFF)
-endif ()
-if (NOT FMT_CAN_MODULE)
-  set(FMT_MODULE OFF)
-  message(STATUS "Module support is disabled.")
-endif ()
 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'.")
@@ -101,6 +162,10 @@ set(FMT_SYSTEM_HEADERS_ATTRIBUTE "")
 if (FMT_SYSTEM_HEADERS)
   set(FMT_SYSTEM_HEADERS_ATTRIBUTE SYSTEM)
 endif ()
+if(CMAKE_SYSTEM_NAME STREQUAL "MSDOS")
+  set(FMT_TEST OFF)
+  message(STATUS "MSDOS is incompatible with gtest")
+endif()
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)
@@ -118,23 +183,15 @@ message(STATUS "Version: ${FMT_VERSION}")
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 
 if (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
-  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/bin)
 endif ()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
   "${CMAKE_CURRENT_SOURCE_DIR}/support/cmake")
 
-include(cxx14)
+include(CheckCXXCompilerFlag)
 include(JoinPaths)
 
-list(FIND CMAKE_CXX_COMPILE_FEATURES "cxx_variadic_templates" index)
-if (${index} GREATER -1)
-  # Use cxx_variadic_templates instead of more appropriate cxx_std_11 for
-  # compatibility with older CMake versions.
-  set(FMT_REQUIRED_FEATURES cxx_variadic_templates)
-endif ()
-message(STATUS "Required features: ${FMT_REQUIRED_FEATURES}")
-
 if (FMT_MASTER_PROJECT AND NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
   set_verbose(CMAKE_CXX_VISIBILITY_PRESET hidden CACHE STRING
               "Preset for the export of private symbols")
@@ -220,16 +277,18 @@ endfunction()
 add_headers(FMT_HEADERS args.h chrono.h color.h compile.h core.h format.h
                         format-inl.h os.h ostream.h printf.h ranges.h std.h
                         xchar.h)
-if (FMT_MODULE)
-  set(FMT_SOURCES src/fmt.cc)
-elseif (FMT_OS)
-  set(FMT_SOURCES src/format.cc src/os.cc)
-else()
-  set(FMT_SOURCES src/format.cc)
+set(FMT_SOURCES src/format.cc)
+if (FMT_OS)
+  set(FMT_SOURCES ${FMT_SOURCES} src/os.cc)
 endif ()
 
-add_library(fmt ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst)
+add_module_library(fmt src/fmt.cc FALLBACK
+                   ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst
+                   IF FMT_MODULE)
 add_library(fmt::fmt ALIAS fmt)
+if (FMT_MODULE)
+  enable_module(fmt)
+endif ()
 
 if (FMT_WERROR)
   target_compile_options(fmt PRIVATE ${WERROR_FLAG})
@@ -237,11 +296,8 @@ endif ()
 if (FMT_PEDANTIC)
   target_compile_options(fmt PRIVATE ${PEDANTIC_COMPILE_FLAGS})
 endif ()
-if (FMT_MODULE)
-  enable_module(fmt)
-endif ()
 
-target_compile_features(fmt INTERFACE ${FMT_REQUIRED_FEATURES})
+target_compile_features(fmt PUBLIC cxx_std_11)
 
 target_include_directories(fmt ${FMT_SYSTEM_HEADERS_ATTRIBUTE} PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
@@ -262,7 +318,7 @@ if (CMAKE_BUILD_TYPE STREQUAL "Debug")
 endif ()
 
 if (BUILD_SHARED_LIBS)
-  target_compile_definitions(fmt PRIVATE FMT_EXPORT INTERFACE FMT_SHARED)
+  target_compile_definitions(fmt PRIVATE FMT_LIB_EXPORT INTERFACE FMT_SHARED)
 endif ()
 if (FMT_SAFE_DURATION_CAST)
   target_compile_definitions(fmt PUBLIC FMT_SAFE_DURATION_CAST)
@@ -272,7 +328,7 @@ add_library(fmt-header-only INTERFACE)
 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_compile_features(fmt-header-only INTERFACE cxx_std_11)
 
 target_include_directories(fmt-header-only ${FMT_SYSTEM_HEADERS_ATTRIBUTE} INTERFACE
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
@@ -339,8 +395,6 @@ if (FMT_INSTALL)
   install(EXPORT ${targets_export_name} DESTINATION ${FMT_CMAKE_DIR}
           NAMESPACE fmt::)
 
-  install(FILES $<TARGET_PDB_FILE:${INSTALL_TARGETS}>
-          DESTINATION ${FMT_LIB_DIR} OPTIONAL)
   install(FILES "${pkgconfig}" DESTINATION "${FMT_PKGCONFIG_DIR}")
 endif ()
 

ChangeLog.rst

@@ -1,3 +1,434 @@
+10.0.0 - 2023-05-09
+-------------------
+
+* Replaced Grisu with a new floating-point formatting algorithm for given
+  precision (`#3262 <https://github.com/fmtlib/fmt/issues/3262>`_,
+  `#2750 <https://github.com/fmtlib/fmt/issues/2750>`_,
+  `#3269 <https://github.com/fmtlib/fmt/pull/3269>`_,
+  `#3276 <https://github.com/fmtlib/fmt/pull/3276>`_).
+  The new algorithm is based on Dragonbox already used for the
+  shortest representation and gives substantial performance improvement:
+
+  .. image:: https://user-images.githubusercontent.com/33922675/
+             211956670-84891a09-6867-47d9-82fc-3230da7abe0f.png
+
+  * Red: new algorithm
+  * Green: new algorithm with ``FMT_USE_FULL_CACHE_DRAGONBOX`` defined to 1
+  * Blue: old algorithm
+
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Replaced ``snprintf``-based hex float formatter with an internal
+  implementation (`#3179 <https://github.com/fmtlib/fmt/pull/3179>`_,
+  `#3203 <https://github.com/fmtlib/fmt/pull/3203>`_).
+  This removes the last usage of ``s(n)printf`` in {fmt}.
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Fixed alignment of floating-point numbers with localization
+  (`#3263 <https://github.com/fmtlib/fmt/issues/3263>`_,
+  `#3272 <https://github.com/fmtlib/fmt/pull/3272>`_).
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Improved C++20 module support
+  (`#3134 <https://github.com/fmtlib/fmt/pull/3134>`_,
+  `#3254 <https://github.com/fmtlib/fmt/pull/3254>`_,
+  `#3386 <https://github.com/fmtlib/fmt/pull/3386>`_,
+  `#3387 <https://github.com/fmtlib/fmt/pull/3387>`_,
+  `#3388 <https://github.com/fmtlib/fmt/pull/3388>`_,
+  `#3392 <https://github.com/fmtlib/fmt/pull/3392>`_,
+  `#3397 <https://github.com/fmtlib/fmt/pull/3397>`_,
+  `#3399 <https://github.com/fmtlib/fmt/pull/3399>`_,
+  `#3400 <https://github.com/fmtlib/fmt/pull/3400>`_).
+  Thanks `@laitingsheng (Tinson Lai) <https://github.com/laitingsheng>`_,
+  `@Orvid (Orvid King) <https://github.com/Orvid>`_,
+  `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_.
+  Switched to the `modules CMake library <https://github.com/vitaut/modules>`_
+  which allows building {fmt} as a C++20 module with clang::
+
+    CXX=clang++ cmake -DFMT_MODULE=ON .
+    make
+
+* Made ``format_as`` work with any user-defined type and not just enums.
+  For example (`godbolt <https://godbolt.org/z/b7rqhq5Kh>`__):
+
+  .. code:: c++
+
+     #include <fmt/format.h>
+
+     struct floaty_mc_floatface {
+       double value;
+     };
+
+     auto format_as(floaty_mc_floatface f) { return f.value; }
+
+     int main() {
+       fmt::print("{:8}\n", floaty_mc_floatface{0.42}); // prints "    0.42"
+     }
+
+* Removed deprecated implicit conversions for enums and conversions to primitive
+  types for compatibility with ``std::format`` and to prevent potential ODR
+  violations. Use ``format_as`` instead.
+
+* Added support for fill, align and width to the time point formatter
+  (`#3237 <https://github.com/fmtlib/fmt/issues/3237>`_,
+  `#3260 <https://github.com/fmtlib/fmt/pull/3260>`_,
+  `#3275 <https://github.com/fmtlib/fmt/pull/3275>`_).
+  For example (`godbolt <https://godbolt.org/z/rKP6MGz6c>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       // prints "    2023"
+       fmt::print("{:>8%Y}\n", std::chrono::system_clock::now());
+     }
+
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Implemented formatting of subseconds
+  (`#2207 <https://github.com/fmtlib/fmt/issues/2207>`_,
+  `#3117 <https://github.com/fmtlib/fmt/issues/3117>`_,
+  `#3115 <https://github.com/fmtlib/fmt/pull/3115>`_,
+  `#3143 <https://github.com/fmtlib/fmt/pull/3143>`_,
+  `#3144 <https://github.com/fmtlib/fmt/pull/3144>`_,
+  `#3349 <https://github.com/fmtlib/fmt/pull/3349>`_).
+  For example (`godbolt <https://godbolt.org/z/45738oGEo>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       // prints 01.234567
+       fmt::print("{:%S}\n", std::chrono::microseconds(1234567));
+     }
+
+  Thanks `@patrickroocks (Patrick Roocks) <https://github.com/patrickroocks>`_
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_,
+  `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Added precision support to ``%S``
+  (`#3148 <https://github.com/fmtlib/fmt/pull/3148>`_).
+  Thanks `@SappyJoy (Stepan Ponomaryov) <https://github.com/SappyJoy>`_
+
+* Added support for ``std::utc_time``
+  (`#3098 <https://github.com/fmtlib/fmt/issues/3098>`_,
+  `#3110 <https://github.com/fmtlib/fmt/pull/3110>`_).
+  Thanks `@patrickroocks (Patrick Roocks) <https://github.com/patrickroocks>`_.
+
+* Switched formatting of ``std::chrono::system_clock`` from local time to UTC
+  for compatibility with the standard
+  (`#3199 <https://github.com/fmtlib/fmt/issues/3199>`_,
+  `#3230 <https://github.com/fmtlib/fmt/pull/3230>`_).
+  Thanks `@ned14 (Niall Douglas) <https://github.com/ned14>`_.
+
+* Added support for ``%Ez`` and ``%Oz`` to chrono formatters.
+  (`#3220 <https://github.com/fmtlib/fmt/issues/3220>`_,
+  `#3222 <https://github.com/fmtlib/fmt/pull/3222>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Improved validation of format specifiers for ``std::chrono::duration``
+  (`#3219 <https://github.com/fmtlib/fmt/issues/3219>`_,
+  `#3232 <https://github.com/fmtlib/fmt/pull/3232>`_).
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Fixed formatting of time points before the epoch
+  (`#3117 <https://github.com/fmtlib/fmt/issues/3117>`_,
+  `#3261 <https://github.com/fmtlib/fmt/pull/3261>`_).
+  For example (`godbolt <https://godbolt.org/z/f7bcznb3W>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       auto t = std::chrono::system_clock::from_time_t(0) -
+                std::chrono::milliseconds(250);
+       fmt::print("{:%S}\n", t); // prints 59.750000000
+     }
+
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Experimental: implemented glibc extension for padding seconds, minutes and
+  hours (`#2959 <https://github.com/fmtlib/fmt/issues/2959>`_,
+  `#3271 <https://github.com/fmtlib/fmt/pull/3271>`_).
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Added a formatter for ``std::exception``
+  (`#2977 <https://github.com/fmtlib/fmt/issues/2977>`_,
+  `#3012 <https://github.com/fmtlib/fmt/issues/3012>`_,
+  `#3062 <https://github.com/fmtlib/fmt/pull/3062>`_,
+  `#3076 <https://github.com/fmtlib/fmt/pull/3076>`_,
+  `#3119 <https://github.com/fmtlib/fmt/pull/3119>`_).
+  For example (`godbolt <https://godbolt.org/z/8xoWGs9e4>`__):
+
+  .. code:: c++
+
+     #include <fmt/std.h>
+     #include <vector>
+
+     int main() {
+       try {
+         std::vector<bool>().at(0);
+       } catch(const std::exception& e) {
+         fmt::print("{}", e);
+       }
+     }
+
+  prints::
+
+    vector<bool>::_M_range_check: __n (which is 0) >= this->size() (which is 0)
+
+  on libstdc++.
+  Thanks `@zach2good (Zach Toogood) <https://github.com/zach2good>`_ and
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Moved ``std::error_code`` formatter from ``fmt/os.h`` to ``fmt/std.h``.
+  (`#3125 <https://github.com/fmtlib/fmt/pull/3125>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Added formatters for standard container adapters: ``std::priority_queue``,
+  ``std::queue`` and ``std::stack``
+  (`#3215 <https://github.com/fmtlib/fmt/issues/3215>`_,
+  `#3279 <https://github.com/fmtlib/fmt/pull/3279>`_).
+  For example (`godbolt <https://godbolt.org/z/74h1xY9qK>`__):
+
+  .. code:: c++
+
+     #include <fmt/ranges.h>
+     #include <stack>
+     #include <vector>
+
+     int main() {
+       auto s = std::stack<bool, std::vector<bool>>();
+       for (auto b: {true, false, true}) s.push(b);
+       fmt::print("{}\n", s); // prints [true, false, true]
+     }
+
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Added a formatter for ``std::optional`` to ``fmt/std.h``.
+  Thanks `@tom-huntington <https://github.com/tom-huntington>`_.
+
+* Fixed formatting of valueless by exception variants
+  (`#3347 <https://github.com/fmtlib/fmt/pull/3347>`_).
+  Thanks `@TheOmegaCarrot <https://github.com/TheOmegaCarrot>`_.
+
+* Made ``fmt::ptr`` accept ``unique_ptr`` with a custom deleter
+  (`#3177 <https://github.com/fmtlib/fmt/pull/3177>`_).
+  Thanks `@hmbj (Hans-Martin B. Jensen) <https://github.com/hmbj>`_.
+
+* Fixed formatting of noncopyable ranges and nested ranges of chars
+  (`#3158 <https://github.com/fmtlib/fmt/pull/3158>`_
+  `#3286 <https://github.com/fmtlib/fmt/issues/3286>`_,
+  `#3290 <https://github.com/fmtlib/fmt/pull/3290>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Fixed issues with formatting of paths and ranges of paths
+  (`#3319 <https://github.com/fmtlib/fmt/issues/3319>`_,
+  `#3321 <https://github.com/fmtlib/fmt/pull/3321>`_
+  `#3322 <https://github.com/fmtlib/fmt/issues/3322>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Improved handling of invalid Unicode in paths.
+
+* Enabled compile-time checks on Apple clang 14 and later
+  (`#3331 <https://github.com/fmtlib/fmt/pull/3331>`_).
+  Thanks `@cloyce (Cloyce D. Spradling) <https://github.com/cloyce>`_.
+
+* Improved compile-time checks of named arguments
+  (`#3105 <https://github.com/fmtlib/fmt/issues/3105>`_,
+  `#3214 <https://github.com/fmtlib/fmt/pull/3214>`_).
+  Thanks `@rbrich (Radek Brich) <https://github.com/rbrich>`_.
+
+* Fixed formatting when both alignment and ``0`` are given
+  (`#3236 <https://github.com/fmtlib/fmt/issues/3236>`_,
+  `#3248 <https://github.com/fmtlib/fmt/pull/3248>`_).
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Improved Unicode support in the experimental file API on Windows
+  (`#3234 <https://github.com/fmtlib/fmt/issues/3234>`_,
+  `#3293 <https://github.com/fmtlib/fmt/pull/3293>`_).
+  Thanks `@Fros1er (Froster) <https://github.com/Fros1er>`_.
+
+* Unified UTF transcoding
+  (`#3416 <https://github.com/fmtlib/fmt/pull/3416>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Added support for UTF-8 digit separators via an experimental locale facet
+  (`#1861 <https://github.com/fmtlib/fmt/issues/1861>`_).
+  For example (`godbolt <https://godbolt.org/z/f7bcznb3W>`__):
+
+  .. code:: c++
+
+     auto loc = std::locale(
+       std::locale(), new fmt::format_facet<std::locale>("’"));
+     auto s = fmt::format(loc, "{:L}", 1000);
+
+  where ``’`` is U+2019 used as a digit separator in the de_CH locale.
+
+* Added an overload of ``formatted_size`` that takes a locale
+  (`#3084 <https://github.com/fmtlib/fmt/issues/3084>`_,
+  `#3087 <https://github.com/fmtlib/fmt/pull/3087>`_).
+  Thanks `@gerboengels <https://github.com/gerboengels>`_.
+
+* Removed the deprecated ``FMT_DEPRECATED_OSTREAM``.
+
+* Fixed a UB when using a null ``std::string_view`` with ``fmt::to_string``
+  or format string compilation
+  (`#3241 <https://github.com/fmtlib/fmt/issues/3241>`_,
+  `#3244 <https://github.com/fmtlib/fmt/pull/3244>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Added ``starts_with`` to the fallback ``string_view`` implementation
+  (`#3080 <https://github.com/fmtlib/fmt/pull/3080>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Added ``fmt::basic_format_string::get()`` for compatibility with
+  ``basic_format_string`` (`#3111 <https://github.com/fmtlib/fmt/pull/3111>`_).
+  Thanks `@huangqinjin <https://github.com/huangqinjin>`_.
+
+* Added ``println`` for compatibility with C++23
+  (`#3267 <https://github.com/fmtlib/fmt/pull/3267>`_).
+  Thanks `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_.
+
+* Improved documentation
+  (`#3108 <https://github.com/fmtlib/fmt/issues/3108>`_,
+  `#3169 <https://github.com/fmtlib/fmt/issues/3169>`_,
+  `#3243 <https://github.com/fmtlib/fmt/pull/3243>`_).
+  `#3404 <https://github.com/fmtlib/fmt/pull/3404>`_).
+  Thanks `@Cleroth <https://github.com/Cleroth>`_ and
+  `@Vertexwahn <https://github.com/Vertexwahn>`_.
+
+* Improved build configuration and tests
+  (`#3118 <https://github.com/fmtlib/fmt/pull/3118>`_,
+  `#3120 <https://github.com/fmtlib/fmt/pull/3120>`_,
+  `#3188 <https://github.com/fmtlib/fmt/pull/3188>`_,
+  `#3189 <https://github.com/fmtlib/fmt/issues/3189>`_,
+  `#3198 <https://github.com/fmtlib/fmt/pull/3198>`_,
+  `#3205 <https://github.com/fmtlib/fmt/pull/3205>`_,
+  `#3207 <https://github.com/fmtlib/fmt/pull/3207>`_,
+  `#3210 <https://github.com/fmtlib/fmt/pull/3210>`_,
+  `#3240 <https://github.com/fmtlib/fmt/pull/3240>`_,
+  `#3256 <https://github.com/fmtlib/fmt/pull/3256>`_,
+  `#3264 <https://github.com/fmtlib/fmt/pull/3264>`_,
+  `#3299 <https://github.com/fmtlib/fmt/issues/3299>`_,
+  `#3302 <https://github.com/fmtlib/fmt/pull/3302>`_,
+  `#3312 <https://github.com/fmtlib/fmt/pull/3312>`_,
+  `#3317 <https://github.com/fmtlib/fmt/issues/3317>`_,
+  `#3328 <https://github.com/fmtlib/fmt/pull/3328>`_,
+  `#3333 <https://github.com/fmtlib/fmt/pull/3333>`_,
+  `#3369 <https://github.com/fmtlib/fmt/pull/3369>`_,
+  `#3373 <https://github.com/fmtlib/fmt/issues/3373>`_,
+  `#3395 <https://github.com/fmtlib/fmt/pull/3395>`_,
+  `#3406 <https://github.com/fmtlib/fmt/pull/3406>`_,
+  `#3411 <https://github.com/fmtlib/fmt/pull/3411>`_).
+  Thanks `@dimztimz (Dimitrij Mijoski) <https://github.com/dimztimz>`_,
+  `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_,
+  `@DavidKorczynski <https://github.com/DavidKorczynski>`_,
+  `@ChrisThrasher (Chris Thrasher) <https://github.com/ChrisThrasher>`_,
+  `@FrancoisCarouge (François Carouge) <https://github.com/FrancoisCarouge>`_,
+  `@kennyweiss (Kenny Weiss) <https://github.com/kennyweiss>`_,
+  `@luzpaz <https://github.com/luzpaz>`_,
+  `@codeinred (Alecto Irene Perez) <https://github.com/codeinred>`_,
+  `@Mixaill (Mikhail Paulyshka) <https://github.com/Mixaill>`_,
+  `@joycebrum (Joyce) <https://github.com/joycebrum>`_,
+  `@kevinhwang (Kevin Hwang) <https://github.com/kevinhwang>`_,
+  `@Vertexwahn <https://github.com/Vertexwahn>`_.
+
+* Fixed a regression in handling empty format specifiers after a colon (``{:}``)
+  (`#3086 <https://github.com/fmtlib/fmt/pull/3086>`_).
+  Thanks `@oxidase (Michael Krasnyk) <https://github.com/oxidase>`_.
+
+* Worked around a broken implementation of ``std::is_constant_evaluated`` in
+  some versions of libstdc++ on clang
+  (`#3247 <https://github.com/fmtlib/fmt/issues/3247>`_,
+  `#3281 <https://github.com/fmtlib/fmt/pull/3281>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_.
+
+* Fixed formatting of volatile variables
+  (`#3068 <https://github.com/fmtlib/fmt/pull/3068>`_).
+
+* Fixed various warnings and compilation issues
+  (`#3057 <https://github.com/fmtlib/fmt/pull/3057>`_,
+  `#3066 <https://github.com/fmtlib/fmt/pull/3066>`_,
+  `#3072 <https://github.com/fmtlib/fmt/pull/3072>`_,
+  `#3082 <https://github.com/fmtlib/fmt/pull/3082>`_,
+  `#3091 <https://github.com/fmtlib/fmt/pull/3091>`_,
+  `#3092 <https://github.com/fmtlib/fmt/issues/3092>`_,
+  `#3093 <https://github.com/fmtlib/fmt/pull/3093>`_,
+  `#3095 <https://github.com/fmtlib/fmt/pull/3095>`_,
+  `#3096 <https://github.com/fmtlib/fmt/issues/3096>`_,
+  `#3097 <https://github.com/fmtlib/fmt/pull/3097>`_,
+  `#3128 <https://github.com/fmtlib/fmt/issues/3128>`_,
+  `#3129 <https://github.com/fmtlib/fmt/pull/3129>`_,
+  `#3137 <https://github.com/fmtlib/fmt/pull/3137>`_,
+  `#3139 <https://github.com/fmtlib/fmt/pull/3139>`_,
+  `#3140 <https://github.com/fmtlib/fmt/issues/3140>`_,
+  `#3142 <https://github.com/fmtlib/fmt/pull/3142>`_,
+  `#3149 <https://github.com/fmtlib/fmt/issues/3149>`_,
+  `#3150 <https://github.com/fmtlib/fmt/pull/3150>`_,
+  `#3154 <https://github.com/fmtlib/fmt/issues/3154>`_,
+  `#3163 <https://github.com/fmtlib/fmt/issues/3163>`_,
+  `#3178 <https://github.com/fmtlib/fmt/issues/3178>`_,
+  `#3184 <https://github.com/fmtlib/fmt/pull/3184>`_,
+  `#3196 <https://github.com/fmtlib/fmt/pull/3196>`_,
+  `#3204 <https://github.com/fmtlib/fmt/issues/3204>`_,
+  `#3206 <https://github.com/fmtlib/fmt/pull/3206>`_,
+  `#3208 <https://github.com/fmtlib/fmt/pull/3208>`_,
+  `#3213 <https://github.com/fmtlib/fmt/issues/3213>`_,
+  `#3216 <https://github.com/fmtlib/fmt/pull/3216>`_,
+  `#3224 <https://github.com/fmtlib/fmt/issues/3224>`_,
+  `#3226 <https://github.com/fmtlib/fmt/issues/3226>`_,
+  `#3228 <https://github.com/fmtlib/fmt/issues/3228>`_,
+  `#3229 <https://github.com/fmtlib/fmt/pull/3229>`_,
+  `#3259 <https://github.com/fmtlib/fmt/pull/3259>`_,
+  `#3274 <https://github.com/fmtlib/fmt/issues/3274>`_,
+  `#3287 <https://github.com/fmtlib/fmt/issues/3287>`_,
+  `#3288 <https://github.com/fmtlib/fmt/pull/3288>`_,
+  `#3292 <https://github.com/fmtlib/fmt/issues/3292>`_,
+  `#3295 <https://github.com/fmtlib/fmt/pull/3295>`_,
+  `#3296 <https://github.com/fmtlib/fmt/pull/3296>`_,
+  `#3298 <https://github.com/fmtlib/fmt/issues/3298>`_,
+  `#3325 <https://github.com/fmtlib/fmt/issues/3325>`_,
+  `#3326 <https://github.com/fmtlib/fmt/pull/3326>`_,
+  `#3334 <https://github.com/fmtlib/fmt/issues/3334>`_,
+  `#3342 <https://github.com/fmtlib/fmt/issues/3342>`_,
+  `#3343 <https://github.com/fmtlib/fmt/pull/3343>`_,
+  `#3351 <https://github.com/fmtlib/fmt/issues/3351>`_,
+  `#3352 <https://github.com/fmtlib/fmt/pull/3352>`_,
+  `#3362 <https://github.com/fmtlib/fmt/pull/3362>`_,
+  `#3365 <https://github.com/fmtlib/fmt/issues/3365>`_,
+  `#3366 <https://github.com/fmtlib/fmt/pull/3366>`_,
+  `#3374 <https://github.com/fmtlib/fmt/pull/3374>`_,
+  `#3377 <https://github.com/fmtlib/fmt/issues/3377>`_,
+  `#3378 <https://github.com/fmtlib/fmt/pull/3378>`_,
+  `#3381 <https://github.com/fmtlib/fmt/issues/3381>`_,
+  `#3398 <https://github.com/fmtlib/fmt/pull/3398>`_,
+  `#3413 <https://github.com/fmtlib/fmt/pull/3413>`_,
+  `#3415 <https://github.com/fmtlib/fmt/issues/3415>`_).
+  Thanks `@phprus (Vladislav Shchapov) <https://github.com/phprus>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@NewbieOrange <https://github.com/NewbieOrange>`_,
+  `@EngineLessCC (VivyaCC) <https://github.com/EngineLessCC>`_,
+  `@asmaloney (Andy Maloney) <https://github.com/asmaloney>`_,
+  `@HazardyKnusperkeks (Björn Schäpers)
+  <https://github.com/HazardyKnusperkeks>`_,
+  `@sergiud (Sergiu Deitsch) <https://github.com/sergiud>`_,
+  `@Youw (Ihor Dutchak) <https://github.com/Youw>`_,
+  `@thesmurph <https://github.com/thesmurph>`_,
+  `@czudziakm (Maksymilian Czudziak) <https://github.com/czudziakm>`_,
+  `@Roman-Koshelev <https://github.com/Roman-Koshelev>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@ShawnZhong (Shawn Zhong) <https://github.com/ShawnZhong>`_,
+  `@russelltg (Russell Greene) <https://github.com/russelltg>`_,
+  `@glebm (Gleb Mazovetskiy) <https://github.com/glebm>`_,
+  `@tmartin-gh <https://github.com/tmartin-gh>`_,
+  `@Zhaojun-Liu (June Liu) <https://github.com/Zhaojun-Liu>`_,
+  `@louiswins (Louis Wilson) <https://github.com/louiswins>`_,
+  `@mogemimi <https://github.com/mogemimi>`_.
+
 9.1.0 - 2022-08-27
 ------------------
 
@@ -105,6 +536,7 @@
   `#2982 <https://github.com/fmtlib/fmt/pull/2982>`_,
   `#2985 <https://github.com/fmtlib/fmt/pull/2985>`_,
   `#2988 <https://github.com/fmtlib/fmt/issues/2988>`_,
+  `#2989 <https://github.com/fmtlib/fmt/issues/2989>`_,
   `#3000 <https://github.com/fmtlib/fmt/issues/3000>`_,
   `#3006 <https://github.com/fmtlib/fmt/issues/3006>`_,
   `#3014 <https://github.com/fmtlib/fmt/issues/3014>`_,
@@ -2260,7 +2692,7 @@
   <https://github.com/kwesolowski>`_.
 
 * Replaced ``FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION`` with the ``FMT_FUZZ``
-  macro to prevent interferring with fuzzing of projects using {fmt}
+  macro to prevent interfering with fuzzing of projects using {fmt}
   (`#1650 <https://github.com/fmtlib/fmt/pull/1650>`_).
   Thanks `@asraa (Asra Ali) <https://github.com/asraa>`_.
 

LICENSE.rst

@@ -1,4 +1,4 @@
-Copyright (c) 2012 - present, Victor Zverovich
+Copyright (c) 2012 - present, Victor Zverovich and {fmt} contributors
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

README.rst

@@ -47,7 +47,8 @@ Features
 * `Format string syntax <https://fmt.dev/latest/syntax.html>`_ similar to Python's
   `format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
 * Fast IEEE 754 floating-point formatter with correct rounding, shortness and
-  round-trip guarantees
+  round-trip guarantees using the `Dragonbox <https://github.com/jk-jeon/dragonbox>`_
+  algorithm
 * Safe `printf implementation
   <https://fmt.dev/latest/api.html#printf-formatting>`_ including the POSIX
   extension for positional arguments
@@ -191,24 +192,24 @@ Speed tests
 ================= ============= ===========
 Library           Method        Run Time, s
 ================= ============= ===========
-libc              printf          1.04
-libc++            std::ostream    3.05
-{fmt} 6.1.1       fmt::print      0.75
-Boost Format 1.67 boost::format   7.24
-Folly Format      folly::format   2.23
+libc              printf          0.91
+libc++            std::ostream    2.49
+{fmt} 9.1         fmt::print      0.74
+Boost Format 1.80 boost::format   6.26
+Folly Format      folly::format   1.87
 ================= ============= ===========
 
-{fmt} is the fastest of the benchmarked methods, ~35% faster than ``printf``.
+{fmt} is the fastest of the benchmarked methods, ~20% faster than ``printf``.
 
 The above results were generated by building ``tinyformat_test.cpp`` on macOS
-10.14.6 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
+12.6.1 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
 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/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>`_)
+IEEE754 ``float`` and ``double`` formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
 and faster than `double-conversion <https://github.com/google/double-conversion>`_ and
 `ryu <https://github.com/ulfjack/ryu>`_:
 
@@ -322,8 +323,10 @@ Projects using this library
 
 * `ccache <https://ccache.dev/>`_: a compiler cache
 
-* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database
+* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: an analytical database
   management system
+  
+* `Contour <https://github.com/contour-terminal/contour/>`_: a modern terminal emulator
 
 * `CUAUV <https://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
@@ -360,6 +363,10 @@ Projects using this library
 
 * `Knuth <https://kth.cash/>`_: high-performance Bitcoin full-node
 
+* `libunicode <https://github.com/contour-terminal/libunicode/>`_: a modern C++17 Unicode library
+
+* `MariaDB <https://mariadb.org/>`_: relational database management system
+
 * `Microsoft Verona <https://github.com/microsoft/verona>`_:
   research programming language for concurrent ownership
 
@@ -413,6 +420,9 @@ Projects using this library
 * `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: open-source
   MMORPG framework
 
+* `🐙 userver framework <https://userver.tech/>`_: open-source asynchronous
+  framework with a rich set of abstractions and database drivers
+
 * `Windows Terminal <https://github.com/microsoft/terminal>`_: the new Windows
   terminal
 
@@ -523,8 +533,7 @@ Maintainers
 -----------
 
 The {fmt} library is maintained by Victor Zverovich (`vitaut
-<https://github.com/vitaut>`_) and Jonathan Müller (`foonathan
-<https://github.com/foonathan>`_) with contributions from many other people.
+<https://github.com/vitaut>`_) with contributions from many other people.
 See `Contributors <https://github.com/fmtlib/fmt/graphs/contributors>`_ and
 `Releases <https://github.com/fmtlib/fmt/releases>`_ for some of the names.
 Let us know if your contribution is not listed or mentioned incorrectly and

doc/api.rst

@@ -31,7 +31,8 @@ Core API
 ``fmt/core.h`` defines the core API which provides main formatting functions
 for ``char``/UTF-8 with C++20 compile-time checks. It has minimal include
 dependencies for better compile times. This header is only beneficial when
-using {fmt} as a library and not in the header-only mode.
+using {fmt} as a library (the default) and not in the header-only mode.
+It also provides ``formatter`` specializations for built-in and string types.
 
 The following functions use :ref:`format string syntax <syntax>`
 similar to that of Python's `str.format
@@ -70,23 +71,182 @@ checked at compile time in C++20. To pass a runtime format string wrap it in
 Compile-Time Format String Checks
 ---------------------------------
 
-Compile-time checks are enabled by default on compilers that support C++20
-``consteval``. On older compilers you can use the ``FMT_STRING`` macro defined
-in ``fmt/format.h`` instead. It requires C++14 and is a no-op in C++11.
+Compile-time format string checks are enabled by default on compilers
+that support C++20 ``consteval``. On older compilers you can use the
+:ref:`FMT_STRING <legacy-checks>`: macro defined in ``fmt/format.h`` instead.
 
-.. doxygendefine:: FMT_STRING
-
-To force the use of legacy compile-time checks, define the preprocessor variable
-``FMT_ENFORCE_COMPILE_STRING``. When set, functions accepting ``FMT_STRING``
-will fail to compile with regular strings. Runtime-checked formatting is still
-possible using ``fmt::vformat``, ``fmt::vprint``, etc.
+Unused arguments are allowed as in Python's `str.format` and ordinary functions.
 
 .. doxygenclass:: fmt::basic_format_string
    :members:
 
 .. doxygentypedef:: fmt::format_string
 
-.. doxygenfunction:: fmt::runtime(string_view) -> basic_runtime<char>
+.. doxygenfunction:: fmt::runtime(string_view) -> runtime_format_string<>
+
+.. _udt:
+
+Formatting User-Defined Types
+-----------------------------
+
+The {fmt} library provides formatters for many standard C++ types.
+See :ref:`fmt/ranges.h <ranges-api>` for ranges and tuples including standard
+containers such as ``std::vector``, :ref:`fmt/chrono.h <chrono-api>` for date
+and time formatting and :ref:`fmt/std.h <std-api>` for other standard library
+types.
+
+To make a user-defined type formattable, specialize the ``formatter<T>`` struct
+template and implement ``parse`` and ``format`` methods::
+
+  #include <fmt/core.h>
+
+  struct point {
+    double x, y;
+  };
+
+  template <> struct fmt::formatter<point> {
+    // Presentation format: 'f' - fixed, 'e' - exponential.
+    char presentation = 'f';
+
+    // Parses format specifications of the form ['f' | 'e'].
+    constexpr auto parse(format_parse_context& ctx) -> format_parse_context::iterator {
+      // [ctx.begin(), ctx.end()) is a character range that contains a part of
+      // the format string starting from the format specifications to be parsed,
+      // e.g. in
+      //
+      //   fmt::format("{:f} - point of interest", point{1, 2});
+      //
+      // the range will contain "f} - point of interest". The formatter should
+      // parse specifiers until '}' or the end of the range. In this example
+      // the formatter should parse the 'f' specifier and return an iterator
+      // pointing to '}'.
+      
+      // Please also note that this character range may be empty, in case of
+      // the "{}" format string, so therefore you should check ctx.begin()
+      // for equality with ctx.end().
+
+      // Parse the presentation format and store it in the formatter:
+      auto it = ctx.begin(), end = ctx.end();
+      if (it != end && (*it == 'f' || *it == 'e')) presentation = *it++;
+
+      // Check if reached the end of the range:
+      if (it != end && *it != '}') ctx.on_error("invalid format");
+
+      // Return an iterator past the end of the parsed range:
+      return it;
+    }
+
+    // Formats the point p using the parsed format specification (presentation)
+    // stored in this formatter.
+    auto format(const point& p, format_context& ctx) const -> format_context::iterator {
+      // ctx.out() is an output iterator to write to.
+      return presentation == 'f'
+                ? fmt::format_to(ctx.out(), "({:.1f}, {:.1f})", p.x, p.y)
+                : fmt::format_to(ctx.out(), "({:.1e}, {:.1e})", p.x, p.y);
+    }
+  };
+
+Then you can pass objects of type ``point`` to any formatting function::
+
+  point p = {1, 2};
+  std::string s = fmt::format("{:f}", p);
+  // s == "(1.0, 2.0)"
+
+You can also reuse existing formatters via inheritance or composition, for
+example::
+
+  // color.h:
+  #include <fmt/core.h>
+
+  enum class color {red, green, blue};
+
+  template <> struct fmt::formatter<color>: formatter<string_view> {
+    // parse is inherited from formatter<string_view>.
+
+    auto format(color c, format_context& ctx) const;
+  };
+
+  // color.cc:
+  #include "color.h"
+  #include <fmt/format.h>
+
+  auto fmt::formatter<color>::format(color c, format_context& ctx) const {
+    string_view name = "unknown";
+    switch (c) {
+    case color::red:   name = "red"; break;
+    case color::green: name = "green"; break;
+    case color::blue:  name = "blue"; break;
+    }
+    return formatter<string_view>::format(name, ctx);
+  }
+
+Note that ``formatter<string_view>::format`` is defined in ``fmt/format.h`` so
+it has to be included in the source file.
+Since ``parse`` is inherited from ``formatter<string_view>`` it will recognize
+all string format specifications, for example
+
+.. code-block:: c++
+
+   fmt::format("{:>10}", color::blue)
+
+will return ``"      blue"``.
+
+You can also write a formatter for a hierarchy of classes::
+
+  // demo.h:
+  #include <type_traits>
+  #include <fmt/core.h>
+
+  struct A {
+    virtual ~A() {}
+    virtual std::string name() const { return "A"; }
+  };
+
+  struct B : A {
+    virtual std::string name() const { return "B"; }
+  };
+
+  template <typename T>
+  struct fmt::formatter<T, std::enable_if_t<std::is_base_of<A, T>::value, char>> :
+      fmt::formatter<std::string> {
+    auto format(const A& a, format_context& ctx) const {
+      return fmt::formatter<std::string>::format(a.name(), ctx);
+    }
+  };
+
+  // demo.cc:
+  #include "demo.h"
+  #include <fmt/format.h>
+
+  int main() {
+    B b;
+    A& a = b;
+    fmt::print("{}", a); // prints "B"
+  }
+
+If a type provides both a ``formatter`` specialization and an implicit
+conversion to a formattable type, the specialization takes precedence over the
+conversion.
+
+For enums {fmt} also provides the ``format_as`` extension API. To format an enum
+via this API define ``format_as`` that takes this enum and converts it to the
+underlying type. ``format_as`` should be defined in the same namespace as the
+enum.
+
+Example (https://godbolt.org/z/r7vvGE1v7)::
+
+  #include <fmt/format.h>
+
+  namespace kevin_namespacy {
+  enum class film {
+    house_of_cards, american_beauty, se7en = 7
+  };
+  auto format_as(film f) { return fmt::underlying(f); }
+  }
+
+  int main() {
+    fmt::print("{}\n", kevin_namespacy::film::se7en); // prints "7"
+  }
 
 Named Arguments
 ---------------
@@ -99,11 +259,11 @@ Argument Lists
 --------------
 
 You can create your own formatting function with compile-time checks and small
-binary footprint, for example (https://godbolt.org/z/oba4Mc):
+binary footprint, for example (https://godbolt.org/z/vajfWEG4b):
 
 .. code:: c++
 
-    #include <fmt/format.h>
+    #include <fmt/core.h>
 
     void vlog(const char* file, int line, fmt::string_view format,
               fmt::format_args args) {
@@ -111,13 +271,12 @@ binary footprint, for example (https://godbolt.org/z/oba4Mc):
       fmt::vprint(format, args);
     }
 
-    template <typename S, typename... Args>
-    void log(const char* file, int line, const S& format, Args&&... args) {
+    template <typename... T>
+    void log(const char* file, int line, fmt::format_string<T...> format, T&&... args) {
       vlog(file, line, format, fmt::make_format_args(args...));
     }
 
-    #define MY_LOG(format, ...) \
-      log(__FILE__, __LINE__, FMT_STRING(format), __VA_ARGS__)
+    #define MY_LOG(format, ...) log(__FILE__, __LINE__, format, __VA_ARGS__)
 
     MY_LOG("invalid squishiness: {}", 42);
 
@@ -156,19 +315,6 @@ Compatibility
 
 .. doxygentypedef:: fmt::string_view
 
-Locale
-------
-
-All formatting is locale-independent by default. Use the ``'L'`` format
-specifier to insert the appropriate number separator characters from the
-locale::
-
-  #include <fmt/core.h>
-  #include <locale>
-
-  std::locale::global(std::locale("en_US.UTF-8"));
-  auto s = fmt::format("{:L}", 1000000);  // s == "1,000,000"
-
 .. _format-api:
 
 Format API
@@ -177,156 +323,6 @@ Format API
 ``fmt/format.h`` defines the full format API providing additional formatting
 functions and locale support.
 
-.. _udt:
-
-Formatting User-Defined Types
------------------------------
-
-The {fmt} library provides formatters for many standard C++ types.
-See :ref:`fmt/ranges.h <ranges-api>` for ranges and tuples including standard
-containers such as ``std::vector``, :ref:`fmt/chrono.h <chrono-api>` for date
-and time formatting and :ref:`fmt/std.h <std-api>` for path and variant 
-formatting.
-
-To make a user-defined type formattable, specialize the ``formatter<T>`` struct
-template and implement ``parse`` and ``format`` methods::
-
-  #include <fmt/format.h>
-
-  struct point {
-    double x, y;
-  };
-
-  template <> struct fmt::formatter<point> {
-    // Presentation format: 'f' - fixed, 'e' - exponential.
-    char presentation = 'f';
-
-    // Parses format specifications of the form ['f' | 'e'].
-    constexpr auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
-      // [ctx.begin(), ctx.end()) is a character range that contains a part of
-      // the format string starting from the format specifications to be parsed,
-      // e.g. in
-      //
-      //   fmt::format("{:f} - point of interest", point{1, 2});
-      //
-      // the range will contain "f} - point of interest". The formatter should
-      // parse specifiers until '}' or the end of the range. In this example
-      // the formatter should parse the 'f' specifier and return an iterator
-      // pointing to '}'.
-      
-      // Please also note that this character range may be empty, in case of
-      // the "{}" format string, so therefore you should check ctx.begin()
-      // for equality with ctx.end().
-
-      // Parse the presentation format and store it in the formatter:
-      auto it = ctx.begin(), end = ctx.end();
-      if (it != end && (*it == 'f' || *it == 'e')) presentation = *it++;
-
-      // Check if reached the end of the range:
-      if (it != end && *it != '}') throw format_error("invalid format");
-
-      // Return an iterator past the end of the parsed range:
-      return it;
-    }
-
-    // Formats the point p using the parsed format specification (presentation)
-    // stored in this formatter.
-    template <typename FormatContext>
-    auto format(const point& p, FormatContext& ctx) const -> decltype(ctx.out()) {
-      // ctx.out() is an output iterator to write to.
-      return presentation == 'f'
-                ? fmt::format_to(ctx.out(), "({:.1f}, {:.1f})", p.x, p.y)
-                : fmt::format_to(ctx.out(), "({:.1e}, {:.1e})", p.x, p.y);
-    }
-  };
-
-Then you can pass objects of type ``point`` to any formatting function::
-
-  point p = {1, 2};
-  std::string s = fmt::format("{:f}", p);
-  // s == "(1.0, 2.0)"
-
-You can also reuse existing formatters via inheritance or composition, for
-example::
-
-  enum class color {red, green, blue};
-
-  template <> struct fmt::formatter<color>: formatter<string_view> {
-    // parse is inherited from formatter<string_view>.
-    template <typename FormatContext>
-    auto format(color c, FormatContext& ctx) const {
-      string_view name = "unknown";
-      switch (c) {
-      case color::red:   name = "red"; break;
-      case color::green: name = "green"; break;
-      case color::blue:  name = "blue"; break;
-      }
-      return formatter<string_view>::format(name, ctx);
-    }
-  };
-
-Since ``parse`` is inherited from ``formatter<string_view>`` it will recognize
-all string format specifications, for example
-
-.. code-block:: c++
-
-   fmt::format("{:>10}", color::blue)
-
-will return ``"      blue"``.
-
-You can also write a formatter for a hierarchy of classes::
-
-  #include <type_traits>
-  #include <fmt/format.h>
-
-  struct A {
-    virtual ~A() {}
-    virtual std::string name() const { return "A"; }
-  };
-
-  struct B : A {
-    virtual std::string name() const { return "B"; }
-  };
-
-  template <typename T>
-  struct fmt::formatter<T, std::enable_if_t<std::is_base_of<A, T>::value, char>> :
-      fmt::formatter<std::string> {
-    template <typename FormatCtx>
-    auto format(const A& a, FormatCtx& ctx) const {
-      return fmt::formatter<std::string>::format(a.name(), ctx);
-    }
-  };
-
-  int main() {
-    B b;
-    A& a = b;
-    fmt::print("{}", a); // prints "B"
-  }
-
-If a type provides both a ``formatter`` specialization and an implicit
-conversion to a formattable type, the specialization takes precedence over the
-conversion.
-
-For enums {fmt} also provides the ``format_as`` extension API. To format an enum
-via this API define ``format_as`` that takes this enum and converts it to the
-underlying type. ``format_as`` should be defined in the same namespace as the
-enum.
-
-Example (https://godbolt.org/z/r7vvGE1v7)::
-
-  #include <fmt/format.h>
-
-  namespace kevin_namespacy {
-  enum class film {
-    house_of_cards, american_beauty, se7en = 7
-  };
-  auto format_as(film f) { return fmt::underlying(f); }
-  }
-
-  int main() {
-    fmt::print("{}\n", kevin_namespacy::film::se7en); // prints "7"
-  }
-
 Literal-Based API
 -----------------
 
@@ -338,7 +334,7 @@ Utilities
 ---------
 
 .. doxygenfunction:: fmt::ptr(T p) -> const void*
-.. doxygenfunction:: fmt::ptr(const std::unique_ptr<T> &p) -> const void*
+.. doxygenfunction:: fmt::ptr(const std::unique_ptr<T, Deleter> &p) -> const void*
 .. doxygenfunction:: fmt::ptr(const std::shared_ptr<T> &p) -> const void*
 
 .. doxygenfunction:: fmt::underlying(Enum e) -> typename std::underlying_type<Enum>::type
@@ -404,6 +400,41 @@ normally don't do any allocations for built-in and string types except for
 non-default floating-point formatting that occasionally falls back on
 ``sprintf``.
 
+Locale
+------
+
+All formatting is locale-independent by default. Use the ``'L'`` format
+specifier to insert the appropriate number separator characters from the
+locale::
+
+  #include <fmt/core.h>
+  #include <locale>
+
+  std::locale::global(std::locale("en_US.UTF-8"));
+  auto s = fmt::format("{:L}", 1000000);  // s == "1,000,000"
+
+``fmt/format.h`` provides the following overloads of formatting functions that
+take ``std::locale`` as a parameter. The locale type is a template parameter to
+avoid the expensive ``<locale>`` include.
+
+.. doxygenfunction:: format(const Locale& loc, format_string<T...> fmt, T&&... args) -> std::string
+.. doxygenfunction:: format_to(OutputIt out, const Locale& loc, format_string<T...> fmt, T&&... args) -> OutputIt
+.. doxygenfunction:: formatted_size(const Locale& loc, format_string<T...> fmt, T&&... args) -> size_t
+
+.. _legacy-checks:
+
+Legacy Compile-Time Format String Checks
+----------------------------------------
+
+``FMT_STRING`` enables compile-time checks on older compilers. It requires C++14
+or later and is a no-op in C++11.
+
+.. doxygendefine:: FMT_STRING
+
+To force the use of legacy compile-time checks, define the preprocessor variable
+``FMT_ENFORCE_COMPILE_STRING``. When set, functions accepting ``FMT_STRING``
+will fail to compile with regular strings.
+
 .. _ranges-api:
 
 Range and Tuple Formatting
@@ -477,6 +508,7 @@ Standard Library Types Formatting
 * `std::thread::id <https://en.cppreference.com/w/cpp/thread/thread/id>`_
 * `std::monostate <https://en.cppreference.com/w/cpp/utility/variant/monostate>`_
 * `std::variant <https://en.cppreference.com/w/cpp/utility/variant/variant>`_
+* `std::optional <https://en.cppreference.com/w/cpp/utility/optional>`_
 
 Formatting Variants
 -------------------

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', '8.0.1', '8.1.0', '8.1.1', '9.0.0', '9.1.0']
+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', '9.0.0', '9.1.0', '10.0.0']
 
 class Pip:
   def __init__(self, venv_dir):
@@ -83,8 +83,7 @@ def build_docs(version='dev', **kwargs):
   internal_symbols = [
     'fmt::detail::.*',
     'basic_data<>',
-    'fmt::type_identity',
-    'fmt::dynamic_formatter'
+    'fmt::type_identity'
   ]
   noisy_warnings = [
     'warning: (Compound|Member .* of class) (' + '|'.join(internal_symbols) + \

doc/syntax.rst

@@ -109,8 +109,8 @@ Note that unless a minimum field width is defined, the field width will always
 be the same size as the data to fill it, so that the alignment option has no
 meaning in this case.
 
-The *sign* option is only valid for number types, and can be one of the
-following:
+The *sign* option is only valid for floating point and signed integer types,
+and can be one of the following:
 
 +---------+------------------------------------------------------------+
 | Option  | Meaning                                                    |
@@ -304,8 +304,8 @@ The available presentation types for pointers are:
 Chrono Format Specifications
 ============================
 
-Format specifications for chrono types and ``std::tm`` have the following
-syntax:
+Format specifications for chrono duration and time point types as well as
+``std::tm`` have the following syntax:
 
 .. productionlist:: sf
    chrono_format_spec: [[`fill`]`align`][`width`]["." `precision`][`chrono_specs`]
@@ -321,20 +321,89 @@ syntax:
 Literal chars are copied unchanged to the output. Precision is valid only for
 ``std::chrono::duration`` types with a floating-point representation type.
 
-The available presentation types (*chrono_type*) for chrono durations and time
-points are:
+The available presentation types (*chrono_type*) are:
 
 +---------+--------------------------------------------------------------------+
 | Type    | Meaning                                                            |
 +=========+====================================================================+
+| ``'a'`` | The abbreviated weekday name, e.g. "Sat". If the value does not    |
+|         | contain a valid weekday, an exception of type ``format_error`` is  |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'A'`` | The full weekday name, e.g. "Saturday". If the value does not      |
+|         | contain a valid weekday, an exception of type ``format_error`` is  |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'b'`` | The abbreviated month name, e.g. "Nov". If the value does not      |
+|         | contain a valid month, an exception of type ``format_error`` is    |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'B'`` | The full month name, e.g. "November". If the value does not        |
+|         | contain a valid month, an exception of type ``format_error`` is    |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'c'`` | The date and time representation, e.g. "Sat Nov 12 22:04:00 1955". |
+|         | The modified command ``%Ec`` produces the locale's alternate date  |
+|         | and time representation.                                           |
++---------+--------------------------------------------------------------------+
+| ``'C'`` | The year divided by 100 using floored division, e.g. "55". If the  |
+|         | result is a single decimal digit, it is prefixed with 0.           |
+|         | The modified command ``%EC`` produces the locale's alternative     |
+|         | representation of the century.                                     |
++---------+--------------------------------------------------------------------+
+| ``'d'`` | The day of month as a decimal number. If the result is a single    |
+|         | decimal digit, it is prefixed with 0. The modified command ``%Od`` |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'D'`` | Equivalent to ``%m/%d/%y``, e.g. "11/12/55".                       |
++---------+--------------------------------------------------------------------+
+| ``'e'`` | The day of month as a decimal number. If the result is a single    |
+|         | decimal digit, it is prefixed with a space. The modified command   |
+|         | ``%Oe`` produces the locale's alternative representation.          |
++---------+--------------------------------------------------------------------+
+| ``'F'`` | Equivalent to ``%Y-%m-%d``, e.g. "1955-11-12".                     |
++---------+--------------------------------------------------------------------+
+| ``'g'`` | The last two decimal digits of the ISO week-based year. If the     |
+|         | result is a single digit it is prefixed by 0.                      |
++---------+--------------------------------------------------------------------+
+| ``'G'`` | The ISO week-based year as a decimal number. If the result is less |
+|         | than four digits it is left-padded with 0 to four digits.          |
++---------+--------------------------------------------------------------------+
+| ``'h'`` | Equivalent to ``%b``, e.g. "Nov".                                  |
++---------+--------------------------------------------------------------------+
 | ``'H'`` | The hour (24-hour clock) as a decimal number. If the result is a   |
 |         | single digit, it is prefixed with 0. The modified command ``%OH``  |
 |         | produces the locale's alternative representation.                  |
 +---------+--------------------------------------------------------------------+
+| ``'I'`` | The hour (12-hour clock) as a decimal number. If the result is a   |
+|         | single digit, it is prefixed with 0. The modified command ``%OI``  |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'j'`` | If the type being formatted is a specialization of duration, the   |
+|         | decimal number of days without padding. Otherwise, the day of the  |
+|         | year as a decimal number. Jan 1 is 001. If the result is less than |
+|         | three digits, it is left-padded with 0 to three digits.            |
++---------+--------------------------------------------------------------------+
+| ``'m'`` | The month as a decimal number. Jan is 01. If the result is a       |
+|         | single digit, it is prefixed with 0. The modified command ``%Om``  |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
 | ``'M'`` | The minute as a decimal number. If the result is a single digit,   |
 |         | it is prefixed with 0. The modified command ``%OM`` produces the   |
 |         | locale's alternative representation.                               |
 +---------+--------------------------------------------------------------------+
+| ``'n'`` | A new-line character.                                              |
++---------+--------------------------------------------------------------------+
+| ``'p'`` | The AM/PM designations associated with a 12-hour clock.            |
++---------+--------------------------------------------------------------------+
+| ``'q'`` | The duration's unit suffix.                                        |
++---------+--------------------------------------------------------------------+
+| ``'Q'`` | The duration's numeric value (as if extracted via ``.count()``).   |
++---------+--------------------------------------------------------------------+
+| ``'r'`` | The 12-hour clock time, e.g. "10:04:00 PM".                        |
++---------+--------------------------------------------------------------------+
+| ``'R'`` | Equivalent to ``%H:%M``, e.g. "22:04".                             |
++---------+--------------------------------------------------------------------+
 | ``'S'`` | Seconds as a decimal number. If the number of seconds is less than |
 |         | 10, the result is prefixed with 0. If the precision of the input   |
 |         | cannot be exactly represented with seconds, then the format is a   |
@@ -345,9 +414,66 @@ points are:
 |         | decimal point is localized according to the locale. The modified   |
 |         | command ``%OS`` produces the locale's alternative representation.  |
 +---------+--------------------------------------------------------------------+
+| ``'t'`` | A horizontal-tab character.                                        |
++---------+--------------------------------------------------------------------+
+| ``'T'`` | Equivalent to ``%H:%M:%S``.                                        |
++---------+--------------------------------------------------------------------+
+| ``'u'`` | The ISO weekday as a decimal number (1-7), where Monday is 1. The  |
+|         | modified command ``%Ou`` produces the locale's alternative         |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'U'`` | The week number of the year as a decimal number. The first Sunday  |
+|         | of the year is the first day of week 01. Days of the same year     |
+|         | prior to that are in week 00. If the result is a single digit, it  |
+|         | is prefixed with 0. The modified command ``%OU`` produces the      |
+|         | locale's alternative representation.                               |
++---------+--------------------------------------------------------------------+
+| ``'V'`` | The ISO week-based week number as a decimal number. If the result  |
+|         | is a single digit, it is prefixed with 0. The modified command     |
+|         | ``%OV`` produces the locale's alternative representation.          |
++---------+--------------------------------------------------------------------+
+| ``'w'`` | The weekday as a decimal number (0-6), where Sunday is 0.          |
+|         | The modified command ``%Ow`` produces the locale's alternative     |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'W'`` | The week number of the year as a decimal number. The first Monday  |
+|         | of the year is the first day of week 01. Days of the same year     |
+|         | prior to that are in week 00. If the result is a single digit, it  |
+|         | is prefixed with 0. The modified command ``%OW`` produces the      |
+|         | locale's alternative representation.                               |
++---------+--------------------------------------------------------------------+
+| ``'x'`` | The date representation, e.g. "11/12/55". The modified command     |
+|         | ``%Ex`` produces the locale's alternate date representation.       |
++---------+--------------------------------------------------------------------+
+| ``'X'`` | The time representation, e.g. "10:04:00". The modified command     |
+|         | ``%EX`` produces the locale's alternate time representation.       |
++---------+--------------------------------------------------------------------+
+| ``'y'`` | The last two decimal digits of the year. If the result is a single |
+|         | digit it is prefixed by 0. The modified command ``%Oy`` produces   |
+|         | the locale's alternative representation. The modified command      |
+|         | ``%Ey`` produces the locale's alternative representation of offset |
+|         | from ``%EC`` (year only).                                          |
++---------+--------------------------------------------------------------------+
+| ``'Y'`` | The year as a decimal number. If the result is less than four      |
+|         | digits it is left-padded with 0 to four digits. The modified       |
+|         | command ``%EY`` produces the locale's alternative full year        |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'z'`` | The offset from UTC in the ISO 8601:2004 format. For example -0430 |
+|         | refers to 4 hours 30 minutes behind UTC. If the offset is zero,    |
+|         | +0000 is used. The modified commands ``%Ez`` and ``%Oz`` insert a  |
+|         | ``:`` between the hours and minutes: -04:30. If the offset         |
+|         | information is not available, an exception of type                 |
+|         | ``format_error`` is thrown.                                        |
++---------+--------------------------------------------------------------------+
+| ``'Z'`` | The time zone abbreviation. If the time zone abbreviation is not   |
+|         | available, an exception of type ``format_error`` is thrown.        |
++---------+--------------------------------------------------------------------+
+| ``'%'`` | A % character.                                                     |
++---------+--------------------------------------------------------------------+
 
 Specifiers that have a calendaric component such as ``'d'`` (the day of month)
-are valid only for ``std::tm`` and not durations or time points.
+are valid only for ``std::tm`` and time points but not durations.
 
 .. range-specs:
 
@@ -371,7 +497,7 @@ Examples::
   fmt::format("{}", std::vector{10, 20, 30});
   // Result: [10, 20, 30]
   fmt::format("{::#x}", std::vector{10, 20, 30});
-  // Result: [0xa, 0x14, 0x13]
+  // Result: [0xa, 0x14, 0x1e]
   fmt::format("{}", vector{'h', 'e', 'l', 'l', 'o'});
   // Result: ['h', 'e', 'l', 'l', 'o']
   fmt::format("{::}", vector{'h', 'e', 'l', 'l', 'o'});

include/fmt/color.h

@@ -11,7 +11,7 @@
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 enum class color : uint32_t {
   alice_blue = 0xF0F8FF,               // rgb(240,248,255)
@@ -423,26 +423,6 @@ FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) noexcept {
   return ansi_color_escape<Char>(em);
 }
 
-template <typename Char> inline void fputs(const Char* chars, FILE* stream) {
-  int result = std::fputs(chars, stream);
-  if (result < 0)
-    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
-}
-
-template <> inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) {
-  int result = std::fputws(chars, stream);
-  if (result < 0)
-    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
-}
-
-template <typename Char> inline void reset_color(FILE* stream) {
-  fputs("\x1b[0m", stream);
-}
-
-template <> inline void reset_color<wchar_t>(FILE* stream) {
-  fputs(L"\x1b[0m", stream);
-}
-
 template <typename Char> inline void reset_color(buffer<Char>& buffer) {
   auto reset_color = string_view("\x1b[0m");
   buffer.append(reset_color.begin(), reset_color.end());
@@ -479,17 +459,19 @@ void vformat_to(buffer<Char>& buf, const text_style& ts,
 
 FMT_END_DETAIL_NAMESPACE
 
-template <typename S, typename Char = char_t<S>>
-void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, detail::to_string_view(format), args);
+inline void vprint(std::FILE* f, const text_style& ts, string_view fmt,
+                   format_args args) {
+  // Legacy wide streams are not supported.
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
   if (detail::is_utf8()) {
-    detail::print(f, basic_string_view<Char>(buf.begin(), buf.size()));
-  } else {
-    buf.push_back(Char(0));
-    detail::fputs(buf.data(), f);
+    detail::print(f, string_view(buf.begin(), buf.size()));
+    return;
   }
+  buf.push_back('\0');
+  int result = std::fputs(buf.data(), f);
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
 /**
@@ -566,7 +548,7 @@ OutputIt vformat_to(
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, ts, format_str, args);
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 /**
@@ -645,7 +627,7 @@ FMT_CONSTEXPR auto styled(const T& value, text_style ts)
   return detail::styled_arg<remove_cvref_t<T>>{value, ts};
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COLOR_H_

include/fmt/compile.h

@@ -331,14 +331,14 @@ template <typename T, typename Char> struct parse_specs_result {
   int next_arg_id;
 };
 
-constexpr int manual_indexing_id = -1;
+enum { manual_indexing_id = -1 };
 
 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
                                                   size_t pos, int next_arg_id) {
   str.remove_prefix(pos);
-  auto ctx = compile_parse_context<Char>(str, max_value<int>(), nullptr, {},
-                                         next_arg_id);
+  auto ctx =
+      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
   return {f, pos + fmt::detail::to_unsigned(end - str.data()),
@@ -348,22 +348,18 @@ constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 template <typename Char> struct arg_id_handler {
   arg_ref<Char> arg_id;
 
-  constexpr int operator()() {
+  constexpr int on_auto() {
     FMT_ASSERT(false, "handler cannot be used with automatic indexing");
     return 0;
   }
-  constexpr int operator()(int id) {
+  constexpr int on_index(int id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-  constexpr int operator()(basic_string_view<Char> id) {
+  constexpr int on_name(basic_string_view<Char> id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-
-  constexpr void on_error(const char* message) {
-    FMT_THROW(format_error(message));
-  }
 };
 
 template <typename Char> struct parse_arg_id_result {
@@ -501,7 +497,7 @@ constexpr auto compile(S format_str) {
 #endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
@@ -605,7 +601,7 @@ template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
 }  // namespace literals
 #endif
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COMPILE_H_

include/fmt/format-inl.h

@@ -9,13 +9,9 @@
 #define FMT_FORMAT_INL_H_
 
 #include <algorithm>
-#include <cctype>
 #include <cerrno>  // errno
 #include <climits>
 #include <cmath>
-#include <cstdarg>
-#include <cstring>  // std::memmove
-#include <cwchar>
 #include <exception>
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
@@ -115,16 +111,43 @@ template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref) {
   return '.';
 }
 #endif
+
+FMT_FUNC auto write_loc(appender out, loc_value value,
+                        const format_specs<>& specs, locale_ref loc) -> bool {
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+  auto locale = loc.get<std::locale>();
+  // We cannot use the num_put<char> facet because it may produce output in
+  // a wrong encoding.
+  using facet = format_facet<std::locale>;
+  if (std::has_facet<facet>(locale))
+    return std::use_facet<facet>(locale).put(out, value, specs);
+  return facet(locale).put(out, value, specs);
+#endif
+  return false;
+}
 }  // namespace detail
 
-#if !FMT_MSC_VERSION
-FMT_API FMT_FUNC format_error::~format_error() noexcept = default;
+template <typename Locale> typename Locale::id format_facet<Locale>::id;
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+template <typename Locale> format_facet<Locale>::format_facet(Locale& loc) {
+  auto& numpunct = std::use_facet<std::numpunct<char>>(loc);
+  grouping_ = numpunct.grouping();
+  if (!grouping_.empty()) separator_ = std::string(1, numpunct.thousands_sep());
+}
+
+template <>
+FMT_API FMT_FUNC auto format_facet<std::locale>::do_put(
+    appender out, loc_value val, const format_specs<>& specs) const -> bool {
+  return val.visit(
+      detail::loc_writer<>{out, specs, separator_, grouping_, decimal_point_});
+}
 #endif
 
-FMT_FUNC std::system_error vsystem_error(int error_code, string_view format_str,
+FMT_FUNC std::system_error vsystem_error(int error_code, string_view fmt,
                                          format_args args) {
   auto ec = std::error_code(error_code, std::generic_category());
-  return std::system_error(ec, vformat(format_str, args));
+  return std::system_error(ec, vformat(fmt, args));
 }
 
 namespace detail {
@@ -143,58 +166,8 @@ FMT_CONSTEXPR inline uint64_t rotr(uint64_t n, uint32_t r) noexcept {
   return (n >> r) | (n << (64 - r));
 }
 
-// Computes 128-bit result of multiplication of two 64-bit unsigned integers.
-inline uint128_fallback umul128(uint64_t x, uint64_t y) noexcept {
-#if FMT_USE_INT128
-  auto p = static_cast<uint128_opt>(x) * static_cast<uint128_opt>(y);
-  return {static_cast<uint64_t>(p >> 64), static_cast<uint64_t>(p)};
-#elif defined(_MSC_VER) && defined(_M_X64)
-  auto result = uint128_fallback();
-  result.lo_ = _umul128(x, y, &result.hi_);
-  return result;
-#else
-  const uint64_t mask = static_cast<uint64_t>(max_value<uint32_t>());
-
-  uint64_t a = x >> 32;
-  uint64_t b = x & mask;
-  uint64_t c = y >> 32;
-  uint64_t d = y & mask;
-
-  uint64_t ac = a * c;
-  uint64_t bc = b * c;
-  uint64_t ad = a * d;
-  uint64_t bd = b * d;
-
-  uint64_t intermediate = (bd >> 32) + (ad & mask) + (bc & mask);
-
-  return {ac + (intermediate >> 32) + (ad >> 32) + (bc >> 32),
-          (intermediate << 32) + (bd & mask)};
-#endif
-}
-
 // Implementation of Dragonbox algorithm: https://github.com/jk-jeon/dragonbox.
 namespace dragonbox {
-// Computes upper 64 bits of multiplication of two 64-bit unsigned integers.
-inline uint64_t umul128_upper64(uint64_t x, uint64_t y) noexcept {
-#if FMT_USE_INT128
-  auto p = static_cast<uint128_opt>(x) * static_cast<uint128_opt>(y);
-  return static_cast<uint64_t>(p >> 64);
-#elif defined(_MSC_VER) && defined(_M_X64)
-  return __umulh(x, y);
-#else
-  return umul128(x, y).high();
-#endif
-}
-
-// Computes upper 128 bits of multiplication of a 64-bit unsigned integer and a
-// 128-bit unsigned integer.
-inline uint128_fallback umul192_upper128(uint64_t x,
-                                         uint128_fallback y) noexcept {
-  uint128_fallback r = umul128(x, y.high());
-  r += umul128_upper64(x, y.low());
-  return r;
-}
-
 // Computes upper 64 bits of multiplication of a 32-bit unsigned integer and a
 // 64-bit unsigned integer.
 inline uint64_t umul96_upper64(uint32_t x, uint64_t y) noexcept {
@@ -216,25 +189,13 @@ inline uint64_t umul96_lower64(uint32_t x, uint64_t y) noexcept {
   return x * y;
 }
 
-// Computes floor(log10(pow(2, e))) for e in [-2620, 2620] using the method from
-// https://fmt.dev/papers/Dragonbox.pdf#page=28, section 6.1.
-inline int floor_log10_pow2(int e) noexcept {
-  FMT_ASSERT(e <= 2620 && e >= -2620, "too large exponent");
-  static_assert((-1 >> 1) == -1, "right shift is not arithmetic");
-  return (e * 315653) >> 20;
-}
-
 // Various fast log computations.
-inline int floor_log2_pow10(int e) noexcept {
-  FMT_ASSERT(e <= 1233 && e >= -1233, "too large exponent");
-  return (e * 1741647) >> 19;
-}
 inline int floor_log10_pow2_minus_log10_4_over_3(int e) noexcept {
   FMT_ASSERT(e <= 2936 && e >= -2985, "too large exponent");
   return (e * 631305 - 261663) >> 21;
 }
 
-static constexpr struct {
+FMT_INLINE_VARIABLE constexpr struct {
   uint32_t divisor;
   int shift_amount;
 } div_small_pow10_infos[] = {{10, 16}, {100, 16}};
@@ -288,7 +249,7 @@ inline uint64_t divide_by_10_to_kappa_plus_1(uint64_t n) noexcept {
 }
 
 // Various subroutines using pow10 cache
-template <class T> struct cache_accessor;
+template <typename T> struct cache_accessor;
 
 template <> struct cache_accessor<float> {
   using carrier_uint = float_info<float>::carrier_uint;
@@ -1009,8 +970,23 @@ template <> struct cache_accessor<double> {
       {0xfcf62c1dee382c42, 0x46729e03dd9ed7b6},
       {0x9e19db92b4e31ba9, 0x6c07a2c26a8346d2},
       {0xc5a05277621be293, 0xc7098b7305241886},
-      { 0xf70867153aa2db38,
-        0xb8cbee4fc66d1ea8 }
+      {0xf70867153aa2db38, 0xb8cbee4fc66d1ea8},
+      {0x9a65406d44a5c903, 0x737f74f1dc043329},
+      {0xc0fe908895cf3b44, 0x505f522e53053ff3},
+      {0xf13e34aabb430a15, 0x647726b9e7c68ff0},
+      {0x96c6e0eab509e64d, 0x5eca783430dc19f6},
+      {0xbc789925624c5fe0, 0xb67d16413d132073},
+      {0xeb96bf6ebadf77d8, 0xe41c5bd18c57e890},
+      {0x933e37a534cbaae7, 0x8e91b962f7b6f15a},
+      {0xb80dc58e81fe95a1, 0x723627bbb5a4adb1},
+      {0xe61136f2227e3b09, 0xcec3b1aaa30dd91d},
+      {0x8fcac257558ee4e6, 0x213a4f0aa5e8a7b2},
+      {0xb3bd72ed2af29e1f, 0xa988e2cd4f62d19e},
+      {0xe0accfa875af45a7, 0x93eb1b80a33b8606},
+      {0x8c6c01c9498d8b88, 0xbc72f130660533c4},
+      {0xaf87023b9bf0ee6a, 0xeb8fad7c7f8680b5},
+      { 0xdb68c2ca82ed2a05,
+        0xa67398db9f6820e2 }
 #else
       {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
       {0xce5d73ff402d98e3, 0xfb0a3d212dc81290},
@@ -1034,8 +1010,8 @@ template <> struct cache_accessor<double> {
       {0x8da471a9de737e24, 0x5ceaecfed289e5d3},
       {0xe4d5e82392a40515, 0x0fabaf3feaa5334b},
       {0xb8da1662e7b00a17, 0x3d6a751f3b936244},
-      { 0x95527a5202df0ccb,
-        0x0f37801e0c43ebc9 }
+      {0x95527a5202df0ccb, 0x0f37801e0c43ebc9},
+      {0xf13e34aabb430a15, 0x647726b9e7c68ff0}
 #endif
     };
 
@@ -1138,8 +1114,12 @@ template <> struct cache_accessor<double> {
   }
 };
 
+FMT_FUNC uint128_fallback get_cached_power(int k) noexcept {
+  return cache_accessor<double>::get_cached_power(k);
+}
+
 // Various integer checks
-template <class T>
+template <typename T>
 bool is_left_endpoint_integer_shorter_interval(int exponent) noexcept {
   const int case_shorter_interval_left_endpoint_lower_threshold = 2;
   const int case_shorter_interval_left_endpoint_upper_threshold = 3;
@@ -1150,8 +1130,12 @@ bool is_left_endpoint_integer_shorter_interval(int exponent) noexcept {
 // Remove trailing zeros from n and return the number of zeros removed (float)
 FMT_INLINE int remove_trailing_zeros(uint32_t& n) noexcept {
   FMT_ASSERT(n != 0, "");
+  // Modular inverse of 5 (mod 2^32): (mod_inv_5 * 5) mod 2^32 = 1.
+  // See https://github.com/fmtlib/fmt/issues/3163 for more details.
   const uint32_t mod_inv_5 = 0xcccccccd;
-  const uint32_t mod_inv_25 = mod_inv_5 * mod_inv_5;
+  // Casts are needed to workaround a bug in MSVC 19.22 and older.
+  const uint32_t mod_inv_25 =
+      static_cast<uint32_t>(uint64_t(mod_inv_5) * mod_inv_5);
 
   int s = 0;
   while (true) {
@@ -1165,7 +1149,6 @@ FMT_INLINE int remove_trailing_zeros(uint32_t& n) noexcept {
     n = q;
     s |= 1;
   }
-
   return s;
 }
 
@@ -1223,7 +1206,7 @@ FMT_INLINE int remove_trailing_zeros(uint64_t& n) noexcept {
 }
 
 // The main algorithm for shorter interval case
-template <class T>
+template <typename T>
 FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) noexcept {
   decimal_fp<T> ret_value;
   // Compute k and beta
@@ -1394,17 +1377,6 @@ small_divisor_case_label:
   return ret_value;
 }
 }  // namespace dragonbox
-
-#ifdef _MSC_VER
-FMT_FUNC auto fmt_snprintf(char* buf, size_t size, const char* fmt, ...)
-    -> int {
-  auto args = va_list();
-  va_start(args, fmt);
-  int result = vsnprintf_s(buf, size, _TRUNCATE, fmt, args);
-  va_end(args);
-  return result;
-}
-#endif
 }  // namespace detail
 
 template <> struct formatter<detail::bigint> {
@@ -1413,9 +1385,8 @@ template <> struct formatter<detail::bigint> {
     return ctx.begin();
   }
 
-  template <typename FormatContext>
-  auto format(const detail::bigint& n, FormatContext& ctx) const ->
-      typename FormatContext::iterator {
+  auto format(const detail::bigint& n, format_context& ctx) const
+      -> format_context::iterator {
     auto out = ctx.out();
     bool first = true;
     for (auto i = n.bigits_.size(); i > 0; --i) {
@@ -1474,57 +1445,44 @@ FMT_FUNC std::string vformat(string_view fmt, format_args args) {
 }
 
 namespace detail {
-#ifdef _WIN32
+#ifndef _WIN32
+FMT_FUNC bool write_console(std::FILE*, string_view) { return false; }
+#else
 using dword = conditional_t<sizeof(long) == 4, unsigned long, unsigned>;
 extern "C" __declspec(dllimport) int __stdcall WriteConsoleW(  //
     void*, const void*, dword, dword*, void*);
 
 FMT_FUNC bool write_console(std::FILE* f, string_view text) {
   auto fd = _fileno(f);
-  if (_isatty(fd)) {
-    detail::utf8_to_utf16 u16(string_view(text.data(), text.size()));
-    auto written = detail::dword();
-    if (detail::WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)),
-                              u16.c_str(), static_cast<uint32_t>(u16.size()),
-                              &written, nullptr)) {
-      return true;
-    }
-  }
-  // We return false if the file descriptor was not TTY, or it was but
-  // SetConsoleW failed which can happen if the output has been redirected to
-  // NUL. In both cases when we return false, we should attempt to do regular
-  // write via fwrite or std::ostream::write.
-  return false;
-}
-#endif
-
-FMT_FUNC void print(std::FILE* f, string_view text) {
-#ifdef _WIN32
-  if (write_console(f, text)) return;
-#endif
-  detail::fwrite_fully(text.data(), 1, text.size(), f);
-}
-}  // namespace detail
-
-FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) {
-  memory_buffer buffer;
-  detail::vformat_to(buffer, format_str, args);
-  detail::print(f, {buffer.data(), buffer.size()});
+  if (!_isatty(fd)) return false;
+  auto u16 = utf8_to_utf16(text);
+  auto written = dword();
+  return WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)), u16.c_str(),
+                       static_cast<uint32_t>(u16.size()), &written, nullptr);
 }
 
-#ifdef _WIN32
 // Print assuming legacy (non-Unicode) encoding.
-FMT_FUNC void detail::vprint_mojibake(std::FILE* f, string_view format_str,
-                                      format_args args) {
-  memory_buffer buffer;
-  detail::vformat_to(buffer, format_str,
+FMT_FUNC void vprint_mojibake(std::FILE* f, string_view fmt, format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt,
                      basic_format_args<buffer_context<char>>(args));
   fwrite_fully(buffer.data(), 1, buffer.size(), f);
 }
 #endif
 
-FMT_FUNC void vprint(string_view format_str, format_args args) {
-  vprint(stdout, format_str, args);
+FMT_FUNC void print(std::FILE* f, string_view text) {
+  if (!write_console(f, text)) fwrite_fully(text.data(), 1, text.size(), f);
+}
+}  // namespace detail
+
+FMT_FUNC void vprint(std::FILE* f, string_view fmt, format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt, args);
+  detail::print(f, {buffer.data(), buffer.size()});
+}
+
+FMT_FUNC void vprint(string_view fmt, format_args args) {
+  vprint(stdout, fmt, args);
 }
 
 namespace detail {

include/fmt/os.h

@@ -71,7 +71,7 @@
 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 /**
   \rst
@@ -120,48 +120,10 @@ template <typename Char> class basic_cstring_view {
 using cstring_view = basic_cstring_view<char>;
 using wcstring_view = basic_cstring_view<wchar_t>;
 
-template <typename Char> struct formatter<std::error_code, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    out = detail::write_bytes(out, ec.category().name(),
-                              basic_format_specs<Char>());
-    out = detail::write<Char>(out, Char(':'));
-    out = detail::write<Char>(out, ec.value());
-    return out;
-  }
-};
-
 #ifdef _WIN32
 FMT_API const std::error_category& system_category() noexcept;
 
 FMT_BEGIN_DETAIL_NAMESPACE
-// A converter from UTF-16 to UTF-8.
-// It is only provided for Windows since other systems support UTF-8 natively.
-class utf16_to_utf8 {
- private:
-  memory_buffer buffer_;
-
- public:
-  utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(basic_string_view<wchar_t> s);
-  operator string_view() const { return string_view(&buffer_[0], size()); }
-  size_t size() const { return buffer_.size() - 1; }
-  const char* c_str() const { return &buffer_[0]; }
-  std::string str() const { return std::string(&buffer_[0], size()); }
-
-  // Performs conversion returning a system error code instead of
-  // throwing exception on conversion error. This method may still throw
-  // in case of memory allocation error.
-  FMT_API int convert(basic_string_view<wchar_t> s);
-};
-
 FMT_API void format_windows_error(buffer<char>& out, int error_code,
                                   const char* message) noexcept;
 FMT_END_DETAIL_NAMESPACE
@@ -355,6 +317,12 @@ class FMT_API file {
   // Creates a buffered_file object associated with this file and detaches
   // this file object from the file.
   buffered_file fdopen(const char* mode);
+
+#  if defined(_WIN32) && !defined(__MINGW32__)
+  // Opens a file and constructs a file object representing this file by
+  // wcstring_view filename. Windows only.
+  static file open_windows_file(wcstring_view path, int oflag);
+#  endif
 };
 
 // Returns the memory page size.
@@ -397,6 +365,28 @@ struct ostream_params {
 #  endif
 };
 
+class file_buffer final : public buffer<char> {
+  file file_;
+
+  FMT_API void grow(size_t) override;
+
+ public:
+  FMT_API file_buffer(cstring_view path, const ostream_params& params);
+  FMT_API file_buffer(file_buffer&& other);
+  FMT_API ~file_buffer();
+
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size() * sizeof(data()[0]));
+    clear();
+  }
+
+  void close() {
+    flush();
+    file_.close();
+  }
+};
+
 FMT_END_DETAIL_NAMESPACE
 
 // Added {} below to work around default constructor error known to
@@ -404,49 +394,32 @@ FMT_END_DETAIL_NAMESPACE
 constexpr detail::buffer_size buffer_size{};
 
 /** A fast output stream which is not thread-safe. */
-class FMT_API ostream final : private detail::buffer<char> {
+class FMT_API ostream {
  private:
-  file file_;
-
-  void grow(size_t) override;
+  FMT_MSC_WARNING(suppress : 4251)
+  detail::file_buffer buffer_;
 
   ostream(cstring_view path, const detail::ostream_params& params)
-      : file_(path, params.oflag) {
-    set(new char[params.buffer_size], params.buffer_size);
-  }
+      : buffer_(path, params) {}
 
  public:
-  ostream(ostream&& other)
-      : detail::buffer<char>(other.data(), other.size(), other.capacity()),
-        file_(std::move(other.file_)) {
-    other.clear();
-    other.set(nullptr, 0);
-  }
-  ~ostream() {
-    flush();
-    delete[] data();
-  }
+  ostream(ostream&& other) : buffer_(std::move(other.buffer_)) {}
 
-  void flush() {
-    if (size() == 0) return;
-    file_.write(data(), size());
-    clear();
-  }
+  ~ostream();
+
+  void flush() { buffer_.flush(); }
 
   template <typename... T>
   friend ostream output_file(cstring_view path, T... params);
 
-  void close() {
-    flush();
-    file_.close();
-  }
+  void close() { buffer_.close(); }
 
   /**
     Formats ``args`` according to specifications in ``fmt`` and writes the
     output to the file.
    */
   template <typename... T> void print(format_string<T...> fmt, T&&... args) {
-    vformat_to(detail::buffer_appender<char>(*this), fmt,
+    vformat_to(detail::buffer_appender<char>(buffer_), fmt,
                fmt::make_format_args(args...));
   }
 };
@@ -472,7 +445,7 @@ inline ostream output_file(cstring_view path, T... params) {
 }
 #endif  // FMT_USE_FCNTL
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_OS_H_

include/fmt/ostream.h

@@ -8,8 +8,8 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
-#include <fstream>
-#include <ostream>
+#include <fstream>  // std::filebuf
+
 #if defined(_WIN32) && defined(__GLIBCXX__)
 #  include <ext/stdio_filebuf.h>
 #  include <ext/stdio_sync_filebuf.h>
@@ -21,48 +21,14 @@
 
 FMT_BEGIN_NAMESPACE
 
-template <typename OutputIt, typename Char> class basic_printf_context;
-
 namespace detail {
 
-// Checks if T has a user-defined operator<<.
-template <typename T, typename Char, typename Enable = void>
-class is_streamable {
- private:
-  template <typename U>
-  static auto test(int)
-      -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>()
-                              << std::declval<U>()) != 0>;
-
-  template <typename> static auto test(...) -> std::false_type;
-
-  using result = decltype(test<T>(0));
-
- public:
-  is_streamable() = default;
-
-  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_convertible<T, fmt::basic_string_view<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 {};
-
 // Generate a unique explicit instantion in every translation unit using a tag
 // type in an anonymous namespace.
 namespace {
 struct file_access_tag {};
 }  // namespace
-template <class Tag, class BufType, FILE* BufType::*FileMemberPtr>
+template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
 class file_access {
   friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
 };
@@ -84,8 +50,8 @@ inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
 #elif defined(_WIN32) && defined(__GLIBCXX__)
   auto* rdbuf = os.rdbuf();
   FILE* c_file;
-  if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
-    c_file = fbuf->file();
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    c_file = sfbuf->file();
   else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
     c_file = fbuf->file();
   else
@@ -145,7 +111,7 @@ struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
   auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
       -> OutputIt {
     auto buffer = basic_memory_buffer<Char>();
-    format_value(buffer, value, ctx.locale());
+    detail::format_value(buffer, value, ctx.locale());
     return formatter<basic_string_view<Char>, Char>::format(
         {buffer.data(), buffer.size()}, ctx);
   }
@@ -180,13 +146,6 @@ auto streamed(const T& value) -> detail::streamed_view<T> {
 
 namespace detail {
 
-// Formats an object of type T that has an overloaded ostream operator<<.
-template <typename T, typename Char>
-struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : basic_ostream_formatter<Char> {
-  using basic_ostream_formatter<Char>::format;
-};
-
 inline void vprint_directly(std::ostream& os, string_view format_str,
                             format_args args) {
   auto buffer = memory_buffer();
@@ -232,6 +191,19 @@ void print(std::wostream& os,
   vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
 }
 
+FMT_MODULE_EXPORT template <typename... T>
+void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+FMT_MODULE_EXPORT
+template <typename... Args>
+void println(std::wostream& os,
+             basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+             Args&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_OSTREAM_H_

include/fmt/printf.h

@@ -14,7 +14,7 @@
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 template <typename T> struct printf_formatter { printf_formatter() = delete; };
 
@@ -81,13 +81,13 @@ class printf_precision_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   int operator()(T value) {
     if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
-      FMT_THROW(format_error("number is too big"));
+      throw_format_error("number is too big");
     return (std::max)(static_cast<int>(value), 0);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
   int operator()(T) {
-    FMT_THROW(format_error("precision is not integer"));
+    throw_format_error("precision is not integer");
     return 0;
   }
 };
@@ -194,12 +194,10 @@ template <typename Char> struct get_cstring {
 // left alignment if it is negative.
 template <typename Char> class printf_width_handler {
  private:
-  using format_specs = basic_format_specs<Char>;
-
-  format_specs& specs_;
+  format_specs<Char>& specs_;
 
  public:
-  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+  explicit printf_width_handler(format_specs<Char>& specs) : specs_(specs) {}
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   unsigned operator()(T value) {
@@ -209,24 +207,31 @@ template <typename Char> class printf_width_handler {
       width = 0 - width;
     }
     unsigned int_max = max_value<int>();
-    if (width > int_max) FMT_THROW(format_error("number is too big"));
+    if (width > int_max) throw_format_error("number is too big");
     return static_cast<unsigned>(width);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
   unsigned operator()(T) {
-    FMT_THROW(format_error("width is not integer"));
+    throw_format_error("width is not integer");
     return 0;
   }
 };
 
+// Workaround for a bug with the XL compiler when initializing
+// printf_arg_formatter's base class.
+template <typename Char>
+auto make_arg_formatter(buffer_appender<Char> iter, format_specs<Char>& s)
+    -> arg_formatter<Char> {
+  return {iter, s, locale_ref()};
+}
+
 // The ``printf`` argument formatter.
 template <typename OutputIt, typename Char>
 class printf_arg_formatter : public arg_formatter<Char> {
  private:
   using base = arg_formatter<Char>;
   using context_type = basic_printf_context<OutputIt, Char>;
-  using format_specs = basic_format_specs<Char>;
 
   context_type& context_;
 
@@ -237,8 +242,8 @@ class printf_arg_formatter : public arg_formatter<Char> {
   }
 
  public:
-  printf_arg_formatter(OutputIt iter, format_specs& s, context_type& ctx)
-      : base{iter, s, locale_ref()}, context_(ctx) {}
+  printf_arg_formatter(OutputIt iter, format_specs<Char>& s, context_type& ctx)
+      : base(make_arg_formatter(iter, s)), context_(ctx) {}
 
   OutputIt operator()(monostate value) { return base::operator()(value); }
 
@@ -247,7 +252,7 @@ class printf_arg_formatter : public arg_formatter<Char> {
     // MSVC2013 fails to compile separate overloads for bool and Char so use
     // std::is_same instead.
     if (std::is_same<T, Char>::value) {
-      format_specs fmt_specs = this->specs;
+      format_specs<Char> fmt_specs = this->specs;
       if (fmt_specs.type != presentation_type::none &&
           fmt_specs.type != presentation_type::chr) {
         return (*this)(static_cast<int>(value));
@@ -300,8 +305,7 @@ class printf_arg_formatter : public arg_formatter<Char> {
 };
 
 template <typename Char>
-void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
-                 const Char* end) {
+void parse_flags(format_specs<Char>& specs, const Char*& it, const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
     case '-':
@@ -328,8 +332,8 @@ void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
 }
 
 template <typename Char, typename GetArg>
-int parse_header(const Char*& it, const Char* end,
-                 basic_format_specs<Char>& specs, GetArg get_arg) {
+int parse_header(const Char*& it, const Char* end, format_specs<Char>& specs,
+                 GetArg get_arg) {
   int arg_index = -1;
   Char c = *it;
   if (c >= '0' && c <= '9') {
@@ -344,7 +348,7 @@ int parse_header(const Char*& it, const Char* end,
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
-        if (value == -1) FMT_THROW(format_error("number is too big"));
+        if (value == -1) throw_format_error("number is too big");
         specs.width = value;
         return arg_index;
       }
@@ -355,7 +359,7 @@ int parse_header(const Char*& it, const Char* end,
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
       specs.width = parse_nonnegative_int(it, end, -1);
-      if (specs.width == -1) FMT_THROW(format_error("number is too big"));
+      if (specs.width == -1) throw_format_error("number is too big");
     } else if (*it == '*') {
       ++it;
       specs.width = static_cast<int>(visit_format_arg(
@@ -365,12 +369,52 @@ int parse_header(const Char*& it, const Char* end,
   return arg_index;
 }
 
+inline auto parse_printf_presentation_type(char c, type t)
+    -> presentation_type {
+  using pt = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  switch (c) {
+  case 'd':
+    return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o':
+    return in(t, integral_set) ? pt::oct : pt::none;
+  case 'x':
+    return in(t, integral_set) ? pt::hex_lower : pt::none;
+  case 'X':
+    return in(t, integral_set) ? pt::hex_upper : pt::none;
+  case 'a':
+    return in(t, float_set) ? pt::hexfloat_lower : pt::none;
+  case 'A':
+    return in(t, float_set) ? pt::hexfloat_upper : pt::none;
+  case 'e':
+    return in(t, float_set) ? pt::exp_lower : pt::none;
+  case 'E':
+    return in(t, float_set) ? pt::exp_upper : pt::none;
+  case 'f':
+    return in(t, float_set) ? pt::fixed_lower : pt::none;
+  case 'F':
+    return in(t, float_set) ? pt::fixed_upper : pt::none;
+  case 'g':
+    return in(t, float_set) ? pt::general_lower : pt::none;
+  case 'G':
+    return in(t, float_set) ? pt::general_upper : pt::none;
+  case 'c':
+    return in(t, integral_set) ? pt::chr : pt::none;
+  case 's':
+    return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p':
+    return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:
+    return pt::none;
+  }
+}
+
 template <typename Char, typename Context>
 void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
              basic_format_args<Context> args) {
-  using OutputIt = buffer_appender<Char>;
-  auto out = OutputIt(buf);
-  auto context = basic_printf_context<OutputIt, Char>(out, args);
+  using iterator = buffer_appender<Char>;
+  auto out = iterator(buf);
+  auto context = basic_printf_context<iterator, Char>(out, args);
   auto parse_ctx = basic_printf_parse_context<Char>(format);
 
   // Returns the argument with specified index or, if arg_index is -1, the next
@@ -387,26 +431,25 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
   const Char* end = parse_ctx.end();
   auto it = start;
   while (it != end) {
-    if (!detail::find<false, Char>(it, end, '%', it)) {
-      it = end;  // detail::find leaves it == nullptr if it doesn't find '%'
+    if (!find<false, Char>(it, end, '%', it)) {
+      it = end;  // find leaves it == nullptr if it doesn't find '%'.
       break;
     }
     Char c = *it++;
     if (it != end && *it == c) {
-      out = detail::write(
-          out, basic_string_view<Char>(start, detail::to_unsigned(it - start)));
+      out = write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
       start = ++it;
       continue;
     }
-    out = detail::write(out, basic_string_view<Char>(
-                                 start, detail::to_unsigned(it - 1 - start)));
+    out =
+        write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
 
-    basic_format_specs<Char> specs;
+    auto specs = format_specs<Char>();
     specs.align = align::right;
 
     // Parse argument index, flags and width.
     int arg_index = parse_header(it, end, specs, get_arg);
-    if (arg_index == 0) parse_ctx.on_error("argument not found");
+    if (arg_index == 0) throw_format_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
@@ -417,7 +460,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
       } else if (c == '*') {
         ++it;
         specs.precision = static_cast<int>(
-            visit_format_arg(detail::printf_precision_handler(), get_arg(-1)));
+            visit_format_arg(printf_precision_handler(), get_arg(-1)));
       } else {
         specs.precision = 0;
       }
@@ -429,17 +472,15 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     if (specs.precision >= 0 && arg.is_integral())
       specs.fill[0] =
           ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
-    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
-      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+    if (specs.precision >= 0 && arg.type() == type::cstring_type) {
+      auto str = visit_format_arg(get_cstring<Char>(), arg);
       auto str_end = str + specs.precision;
       auto nul = std::find(str, str_end, Char());
-      arg = detail::make_arg<basic_printf_context<OutputIt, Char>>(
+      arg = make_arg<basic_printf_context<iterator, Char>>(
           basic_string_view<Char>(
-              str, detail::to_unsigned(nul != str_end ? nul - str
-                                                      : specs.precision)));
+              str, to_unsigned(nul != str_end ? nul - str : specs.precision)));
     }
-    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
-      specs.alt = false;
+    if (specs.alt && visit_format_arg(is_zero_int(), arg)) specs.alt = false;
     if (specs.fill[0] == '0') {
       if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
@@ -451,7 +492,6 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
     Char t = it != end ? *it : 0;
-    using detail::convert_arg;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -490,7 +530,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     }
 
     // Parse type.
-    if (it == end) FMT_THROW(format_error("invalid format string"));
+    if (it == end) throw_format_error("invalid format string");
     char type = static_cast<char>(*it++);
     if (arg.is_integral()) {
       // Normalize type.
@@ -501,22 +541,21 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         break;
       case 'c':
         visit_format_arg(
-            detail::char_converter<basic_printf_context<OutputIt, Char>>(arg),
-            arg);
+            char_converter<basic_printf_context<iterator, Char>>(arg), arg);
         break;
       }
     }
-    specs.type = parse_presentation_type(type);
+    specs.type = parse_printf_presentation_type(type, arg.type());
     if (specs.type == presentation_type::none)
-      parse_ctx.on_error("invalid type specifier");
+      throw_format_error("invalid format specifier");
 
     start = it;
 
     // Format argument.
     out = visit_format_arg(
-        detail::printf_arg_formatter<OutputIt, Char>(out, specs, context), arg);
+        printf_arg_formatter<iterator, Char>(out, specs, context), arg);
   }
-  detail::write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
+  write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
 }
 FMT_END_DETAIL_NAMESPACE
 
@@ -559,9 +598,9 @@ inline auto vsprintf(
     const S& fmt,
     basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
     -> std::basic_string<Char> {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, detail::to_string_view(fmt), args);
-  return to_string(buffer);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, detail::to_string_view(fmt), args);
+  return to_string(buf);
 }
 
 /**
@@ -586,10 +625,10 @@ inline auto vfprintf(
     std::FILE* f, const S& fmt,
     basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
     -> int {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, detail::to_string_view(fmt), args);
-  size_t size = buffer.size();
-  return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, detail::to_string_view(fmt), args);
+  size_t size = buf.size();
+  return std::fwrite(buf.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
 }
@@ -634,7 +673,7 @@ inline auto printf(const S& fmt, const T&... args) -> int {
       fmt::make_format_args<basic_printf_context_t<char_t<S>>>(args...));
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_PRINTF_H_

include/fmt/ranges.h

@@ -22,27 +22,25 @@ FMT_BEGIN_NAMESPACE
 
 namespace detail {
 
-template <typename RangeT, typename OutputIterator>
-OutputIterator copy(const RangeT& range, OutputIterator out) {
+template <typename Range, typename OutputIt>
+auto copy(const Range& range, OutputIt out) -> OutputIt {
   for (auto it = range.begin(), end = range.end(); it != end; ++it)
     *out++ = *it;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(const char* str, OutputIterator out) {
+template <typename OutputIt>
+auto copy(const char* str, OutputIt out) -> OutputIt {
   while (*str) *out++ = *str++;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(char ch, OutputIterator out) {
+template <typename OutputIt> auto copy(char ch, OutputIt out) -> OutputIt {
   *out++ = ch;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(wchar_t ch, OutputIterator out) {
+template <typename OutputIt> auto copy(wchar_t ch, OutputIt out) -> OutputIt {
   *out++ = ch;
   return out;
 }
@@ -69,7 +67,7 @@ template <typename T> class is_map {
   template <typename> static void check(...);
 
  public:
-#ifdef FMT_FORMAT_MAP_AS_LIST
+#ifdef FMT_FORMAT_MAP_AS_LIST  // DEPRECATED!
   static constexpr const bool value = false;
 #else
   static constexpr const bool value =
@@ -82,7 +80,7 @@ template <typename T> class is_set {
   template <typename> static void check(...);
 
  public:
-#ifdef FMT_FORMAT_SET_AS_LIST
+#ifdef FMT_FORMAT_SET_AS_LIST  // DEPRECATED!
   static constexpr const bool value = false;
 #else
   static constexpr const bool value =
@@ -157,8 +155,9 @@ template <typename T>
 struct has_mutable_begin_end<
     T, void_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 {};
+              // the extra int here is because older versions of MSVC don't
+              // SFINAE properly unless there are distinct types
+              int>> : std::true_type {};
 
 template <typename T>
 struct is_range_<T, void>
@@ -211,41 +210,61 @@ class is_tuple_formattable_ {
   static constexpr const bool value = false;
 };
 template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
-  template <std::size_t... I>
-  static std::true_type check2(index_sequence<I...>,
-                               integer_sequence<bool, (I == I)...>);
+  template <std::size_t... Is>
+  static std::true_type check2(index_sequence<Is...>,
+                               integer_sequence<bool, (Is == Is)...>);
   static std::false_type check2(...);
-  template <std::size_t... I>
+  template <std::size_t... Is>
   static decltype(check2(
-      index_sequence<I...>{},
+      index_sequence<Is...>{},
       integer_sequence<
-          bool, (is_formattable<typename std::tuple_element<I, T>::type,
-                                C>::value)...>{})) check(index_sequence<I...>);
+          bool, (is_formattable<typename std::tuple_element<Is, T>::type,
+                                C>::value)...>{})) check(index_sequence<Is...>);
 
  public:
   static constexpr const bool value =
       decltype(check(tuple_index_sequence<T>{}))::value;
 };
 
-template <class Tuple, class F, size_t... Is>
-void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) noexcept {
+template <typename Tuple, typename F, size_t... Is>
+FMT_CONSTEXPR void for_each(index_sequence<Is...>, Tuple&& t, F&& f) {
   using std::get;
-  // using free function get<I>(T) now.
-  const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
-  (void)_;  // blocks warnings
+  // Using a free function get<Is>(Tuple) now.
+  const int unused[] = {0, ((void)f(get<Is>(t)), 0)...};
+  ignore_unused(unused);
 }
 
-template <class T>
-FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes(
-    T const&) {
-  return {};
+template <typename Tuple, typename F>
+FMT_CONSTEXPR void for_each(Tuple&& t, F&& f) {
+  for_each(tuple_index_sequence<remove_cvref_t<Tuple>>(),
+           std::forward<Tuple>(t), std::forward<F>(f));
 }
 
-template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
-  const auto indexes = get_indexes(tup);
-  for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
+template <typename Tuple1, typename Tuple2, typename F, size_t... Is>
+void for_each2(index_sequence<Is...>, Tuple1&& t1, Tuple2&& t2, F&& f) {
+  using std::get;
+  const int unused[] = {0, ((void)f(get<Is>(t1), get<Is>(t2)), 0)...};
+  ignore_unused(unused);
 }
 
+template <typename Tuple1, typename Tuple2, typename F>
+void for_each2(Tuple1&& t1, Tuple2&& t2, F&& f) {
+  for_each2(tuple_index_sequence<remove_cvref_t<Tuple1>>(),
+            std::forward<Tuple1>(t1), std::forward<Tuple2>(t2),
+            std::forward<F>(f));
+}
+
+namespace tuple {
+// Workaround a bug in MSVC 2019 (v140).
+template <typename Char, typename... T>
+using result_t = std::tuple<formatter<remove_cvref_t<T>, Char>...>;
+
+using std::get;
+template <typename Tuple, typename Char, std::size_t... Is>
+auto get_formatters(index_sequence<Is...>)
+    -> result_t<Char, decltype(get<Is>(std::declval<Tuple>()))...>;
+}  // namespace tuple
+
 #if FMT_MSC_VERSION && FMT_MSC_VERSION < 1920
 // Older MSVC doesn't get the reference type correctly for arrays.
 template <typename R> struct range_reference_type_impl {
@@ -269,45 +288,37 @@ using range_reference_type =
 template <typename Range>
 using uncvref_type = remove_cvref_t<range_reference_type<Range>>;
 
-template <typename Range>
-using uncvref_first_type =
-    remove_cvref_t<decltype(std::declval<range_reference_type<Range>>().first)>;
-
-template <typename Range>
-using uncvref_second_type = remove_cvref_t<
-    decltype(std::declval<range_reference_type<Range>>().second)>;
-
-template <typename OutputIt> OutputIt write_delimiter(OutputIt out) {
-  *out++ = ',';
-  *out++ = ' ';
-  return out;
+template <typename Formatter>
+FMT_CONSTEXPR auto maybe_set_debug_format(Formatter& f, bool set)
+    -> decltype(f.set_debug_format(set)) {
+  f.set_debug_format(set);
 }
+template <typename Formatter>
+FMT_CONSTEXPR void maybe_set_debug_format(Formatter&, ...) {}
 
-template <typename Char, typename OutputIt>
-auto write_range_entry(OutputIt out, basic_string_view<Char> str) -> OutputIt {
-  return write_escaped_string(out, str);
-}
+// These are not generic lambdas for compatibility with C++11.
+template <typename ParseContext> struct parse_empty_specs {
+  template <typename Formatter> FMT_CONSTEXPR void operator()(Formatter& f) {
+    f.parse(ctx);
+    detail::maybe_set_debug_format(f, true);
+  }
+  ParseContext& ctx;
+};
+template <typename FormatContext> struct format_tuple_element {
+  using char_type = typename FormatContext::char_type;
 
-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 T>
+  void operator()(const formatter<T, char_type>& f, const T& v) {
+    if (i > 0)
+      ctx.advance_to(detail::copy_str<char_type>(separator, ctx.out()));
+    ctx.advance_to(f.format(v, ctx));
+    ++i;
+  }
 
-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) {
-  return write_escaped_char(out, v);
-}
-
-template <
-    typename Char, typename OutputIt, typename Arg,
-    FMT_ENABLE_IF(!is_std_string_like<typename std::decay<Arg>::type>::value &&
-                  !std::is_same<Arg, Char>::value)>
-OutputIt write_range_entry(OutputIt out, const Arg& v) {
-  return write<Char>(out, v);
-}
+  int i;
+  FormatContext& ctx;
+  basic_string_view<char_type> separator;
+};
 
 }  // namespace detail
 
@@ -321,29 +332,20 @@ template <typename T, typename C> struct is_tuple_formattable {
       detail::is_tuple_formattable_<T, C>::value;
 };
 
-template <typename TupleT, typename Char>
-struct formatter<TupleT, Char,
-                 enable_if_t<fmt::is_tuple_like<TupleT>::value &&
-                             fmt::is_tuple_formattable<TupleT, Char>::value>> {
+template <typename Tuple, typename Char>
+struct formatter<Tuple, Char,
+                 enable_if_t<fmt::is_tuple_like<Tuple>::value &&
+                             fmt::is_tuple_formattable<Tuple, Char>::value>> {
  private:
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
+
   basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
   basic_string_view<Char> opening_bracket_ =
       detail::string_literal<Char, '('>{};
   basic_string_view<Char> closing_bracket_ =
       detail::string_literal<Char, ')'>{};
 
-  // 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::copy_str<Char>(separator, out);
-      out = detail::write_range_entry<Char>(out, v);
-      ++i;
-    }
-    int i;
-    typename FormatContext::iterator& out;
-    basic_string_view<Char> separator;
-  };
-
  public:
   FMT_CONSTEXPR formatter() {}
 
@@ -359,17 +361,21 @@ struct formatter<TupleT, Char,
 
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it != '}')
+      FMT_THROW(format_error("invalid format specifier"));
+    detail::for_each(formatters_, detail::parse_empty_specs<ParseContext>{ctx});
+    return it;
   }
 
-  template <typename FormatContext = format_context>
-  auto format(const TupleT& values, FormatContext& ctx) const
+  template <typename FormatContext>
+  auto format(const Tuple& value, FormatContext& ctx) const
       -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    out = detail::copy_str<Char>(opening_bracket_, out);
-    detail::for_each(values, format_each<FormatContext>{0, out, separator_});
-    out = detail::copy_str<Char>(closing_bracket_, out);
-    return out;
+    ctx.advance_to(detail::copy_str<Char>(opening_bracket_, ctx.out()));
+    detail::for_each2(
+        formatters_, value,
+        detail::format_tuple_element<FormatContext>{0, ctx, separator_});
+    return detail::copy_str<Char>(closing_bracket_, ctx.out());
   }
 };
 
@@ -398,12 +404,10 @@ template <typename Context> struct range_mapper {
 };
 
 template <typename Char, typename Element>
-using range_formatter_type = conditional_t<
-    is_formattable<Element, Char>::value,
+using range_formatter_type =
     formatter<remove_cvref_t<decltype(range_mapper<buffer_context<Char>>{}.map(
                   std::declval<Element>()))>,
-              Char>,
-    fallback_formatter<Element, Char>>;
+              Char>;
 
 template <typename R>
 using maybe_const_range =
@@ -413,11 +417,8 @@ using maybe_const_range =
 #if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
 template <typename R, typename Char>
 struct is_formattable_delayed
-    : disjunction<
-          is_formattable<uncvref_type<maybe_const_range<R>>, Char>,
-          has_fallback_formatter<uncvref_type<maybe_const_range<R>>, Char>> {};
+    : is_formattable<uncvref_type<maybe_const_range<R>>, Char> {};
 #endif
-
 }  // namespace detail
 
 template <typename T, typename Char, typename Enable = void>
@@ -426,32 +427,16 @@ struct range_formatter;
 template <typename T, typename Char>
 struct range_formatter<
     T, Char,
-    enable_if_t<conjunction<
-        std::is_same<T, remove_cvref_t<T>>,
-        disjunction<is_formattable<T, Char>,
-                    detail::has_fallback_formatter<T, Char>>>::value>> {
+    enable_if_t<conjunction<std::is_same<T, remove_cvref_t<T>>,
+                            is_formattable<T, Char>>::value>> {
  private:
   detail::range_formatter_type<Char, T> underlying_;
-  bool custom_specs_ = false;
   basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
   basic_string_view<Char> opening_bracket_ =
       detail::string_literal<Char, '['>{};
   basic_string_view<Char> closing_bracket_ =
       detail::string_literal<Char, ']'>{};
 
-  template <class U>
-  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, int)
-      -> decltype(u.set_debug_format()) {
-    u.set_debug_format();
-  }
-
-  template <class U>
-  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
-
-  FMT_CONSTEXPR void maybe_set_debug_format() {
-    maybe_set_debug_format(underlying_, 0);
-  }
-
  public:
   FMT_CONSTEXPR range_formatter() {}
 
@@ -473,31 +458,24 @@ struct range_formatter<
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
     auto it = ctx.begin();
     auto end = ctx.end();
-    if (it == end || *it == '}') {
-      maybe_set_debug_format();
-      return it;
-    }
 
-    if (*it == 'n') {
+    if (it != end && *it == 'n') {
       set_brackets({}, {});
       ++it;
     }
 
-    if (*it == '}') {
-      maybe_set_debug_format();
-      return it;
+    if (it != end && *it != '}') {
+      if (*it != ':') FMT_THROW(format_error("invalid format specifier"));
+      ++it;
+    } else {
+      detail::maybe_set_debug_format(underlying_, true);
     }
 
-    if (*it != ':')
-      FMT_THROW(format_error("no other top-level range formatters supported"));
-
-    custom_specs_ = true;
-    ++it;
     ctx.advance_to(it);
     return underlying_.parse(ctx);
   }
 
-  template <typename R, class FormatContext>
+  template <typename R, typename FormatContext>
   auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
     detail::range_mapper<buffer_context<Char>> mapper;
     auto out = ctx.out();
@@ -507,7 +485,6 @@ struct range_formatter<
     auto end = detail::range_end(range);
     for (; it != end; ++it) {
       if (i > 0) out = detail::copy_str<Char>(separator_, out);
-      ;
       ctx.advance_to(out);
       out = underlying_.format(mapper.map(*it), ctx);
       ++i;
@@ -520,13 +497,14 @@ struct range_formatter<
 enum class range_format { disabled, map, set, sequence, string, debug_string };
 
 namespace detail {
-template <typename T> struct range_format_kind_ {
-  static constexpr auto value = std::is_same<range_reference_type<T>, T>::value
-                                    ? range_format::disabled
-                                : is_map<T>::value ? range_format::map
-                                : is_set<T>::value ? range_format::set
-                                                   : range_format::sequence;
-};
+template <typename T>
+struct range_format_kind_
+    : std::integral_constant<range_format,
+                             std::is_same<uncvref_type<T>, T>::value
+                                 ? range_format::disabled
+                             : is_map<T>::value ? range_format::map
+                             : is_set<T>::value ? range_format::set
+                                                : range_format::sequence> {};
 
 template <range_format K, typename R, typename Char, typename Enable = void>
 struct range_default_formatter;
@@ -601,9 +579,6 @@ template <typename Char, typename... T> struct tuple_join_view : detail::view {
       : tuple(t), sep{s} {}
 };
 
-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.
@@ -673,7 +648,42 @@ struct formatter<tuple_join_view<Char, T...>, Char> {
   }
 };
 
-FMT_MODULE_EXPORT_BEGIN
+namespace detail {
+// Check if T has an interface like a container adaptor (e.g. std::stack,
+// std::queue, std::priority_queue).
+template <typename T> class is_container_adaptor_like {
+  template <typename U> static auto check(U* p) -> typename U::container_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename Container> struct all {
+  const Container& c;
+  auto begin() const -> typename Container::const_iterator { return c.begin(); }
+  auto end() const -> typename Container::const_iterator { return c.end(); }
+};
+}  // namespace detail
+
+template <typename T, typename Char>
+struct formatter<T, Char,
+                 enable_if_t<detail::is_container_adaptor_like<T>::value>>
+    : formatter<detail::all<typename T::container_type>, Char> {
+  using all = detail::all<typename T::container_type>;
+  template <typename FormatContext>
+  auto format(const T& t, FormatContext& ctx) const -> decltype(ctx.out()) {
+    struct getter : T {
+      static auto get(const T& t) -> all {
+        return {t.*(&getter::c)};  // Access c through the derived class.
+      }
+    };
+    return formatter<all>::format(getter::get(t), ctx);
+  }
+};
+
+FMT_BEGIN_EXPORT
 
 /**
   \rst
@@ -716,7 +726,7 @@ auto join(std::initializer_list<T> list, string_view sep)
   return join(std::begin(list), std::end(list), sep);
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_

include/fmt/std.h

@@ -8,8 +8,12 @@
 #ifndef FMT_STD_H_
 #define FMT_STD_H_
 
+#include <cstdlib>
+#include <exception>
+#include <memory>
 #include <thread>
 #include <type_traits>
+#include <typeinfo>
 #include <utility>
 
 #include "ostream.h"
@@ -25,6 +29,19 @@
 #  if FMT_HAS_INCLUDE(<variant>)
 #    include <variant>
 #  endif
+#  if FMT_HAS_INCLUDE(<optional>)
+#    include <optional>
+#  endif
+#endif
+
+// GCC 4 does not support FMT_HAS_INCLUDE.
+#if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
+#  include <cxxabi.h>
+// Android NDK with gabi++ library on some architectures does not implement
+// abi::__cxa_demangle().
+#  ifndef __GABIXX_CXXABI_H__
+#    define FMT_HAS_ABI_CXA_DEMANGLE
+#  endif
 #endif
 
 #ifdef __cpp_lib_filesystem
@@ -39,12 +56,13 @@ void write_escaped_path(basic_memory_buffer<Char>& quoted,
 }
 #  ifdef _WIN32
 template <>
-inline void write_escaped_path<char>(basic_memory_buffer<char>& quoted,
+inline void write_escaped_path<char>(memory_buffer& quoted,
                                      const std::filesystem::path& p) {
-  auto s = p.u8string();
-  write_escaped_string<char>(
-      std::back_inserter(quoted),
-      string_view(reinterpret_cast<const char*>(s.c_str()), s.size()));
+  auto buf = basic_memory_buffer<wchar_t>();
+  write_escaped_string<wchar_t>(std::back_inserter(buf), p.native());
+  // Convert UTF-16 to UTF-8.
+  if (!unicode_to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()}))
+    FMT_THROW(std::runtime_error("invalid utf16"));
 }
 #  endif
 template <>
@@ -57,13 +75,19 @@ inline void write_escaped_path<std::filesystem::path::value_type>(
 
 }  // namespace detail
 
+FMT_MODULE_EXPORT
 template <typename Char>
 struct formatter<std::filesystem::path, Char>
     : formatter<basic_string_view<Char>> {
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    auto out = formatter<basic_string_view<Char>>::parse(ctx);
+    this->set_debug_format(false);
+    return out;
+  }
   template <typename FormatContext>
   auto format(const std::filesystem::path& p, FormatContext& ctx) const ->
       typename FormatContext::iterator {
-    basic_memory_buffer<Char> quoted;
+    auto quoted = basic_memory_buffer<Char>();
     detail::write_escaped_path(quoted, p);
     return formatter<basic_string_view<Char>>::format(
         basic_string_view<Char>(quoted.data(), quoted.size()), ctx);
@@ -73,12 +97,58 @@ FMT_END_NAMESPACE
 #endif
 
 FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
 template <typename Char>
 struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
 FMT_END_NAMESPACE
 
+#ifdef __cpp_lib_optional
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename T, typename Char>
+struct formatter<std::optional<T>, Char,
+                 std::enable_if_t<is_formattable<T, Char>::value>> {
+ private:
+  formatter<T, Char> underlying_;
+  static constexpr basic_string_view<Char> optional =
+      detail::string_literal<Char, 'o', 'p', 't', 'i', 'o', 'n', 'a', 'l',
+                             '('>{};
+  static constexpr basic_string_view<Char> none =
+      detail::string_literal<Char, 'n', 'o', 'n', 'e'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, bool set)
+      -> decltype(u.set_debug_format(set)) {
+    u.set_debug_format(set);
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+ public:
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    maybe_set_debug_format(underlying_, true);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(std::optional<T> const& opt, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    if (!opt) return detail::write<Char>(ctx.out(), none);
+
+    auto out = ctx.out();
+    out = detail::write<Char>(out, optional);
+    ctx.advance_to(out);
+    out = underlying_.format(*opt, ctx);
+    return detail::write(out, ')');
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_optional
+
 #ifdef __cpp_lib_variant
 FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
 template <typename Char> struct formatter<std::monostate, Char> {
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
@@ -100,19 +170,16 @@ template <typename T>
 using variant_index_sequence =
     std::make_index_sequence<std::variant_size<T>::value>;
 
-// variant_size and variant_alternative check.
-template <typename T, typename U = void>
-struct is_variant_like_ : std::false_type {};
-template <typename T>
-struct is_variant_like_<T, std::void_t<decltype(std::variant_size<T>::value)>>
-    : std::true_type {};
+template <typename> struct is_variant_like_ : std::false_type {};
+template <typename... Types>
+struct is_variant_like_<std::variant<Types...>> : std::true_type {};
 
-// formattable element check
+// formattable element check.
 template <typename T, typename C> class is_variant_formattable_ {
-  template <std::size_t... I>
+  template <std::size_t... Is>
   static std::conjunction<
-      is_formattable<std::variant_alternative_t<I, T>, C>...>
-      check(std::index_sequence<I...>);
+      is_formattable<std::variant_alternative_t<Is, T>, C>...>
+      check(std::index_sequence<Is...>);
 
  public:
   static constexpr const bool value =
@@ -130,7 +197,6 @@ auto write_variant_alternative(OutputIt out, const T& v) -> OutputIt {
 }
 
 }  // namespace detail
-
 template <typename T> struct is_variant_like {
   static constexpr const bool value = detail::is_variant_like_<T>::value;
 };
@@ -140,6 +206,7 @@ template <typename T, typename C> struct is_variant_formattable {
       detail::is_variant_formattable_<T, C>::value;
 };
 
+FMT_MODULE_EXPORT
 template <typename Variant, typename Char>
 struct formatter<
     Variant, Char,
@@ -156,16 +223,127 @@ struct formatter<
     auto out = ctx.out();
 
     out = detail::write<Char>(out, "variant(");
-    std::visit(
-        [&](const auto& v) {
-          out = detail::write_variant_alternative<Char>(out, v);
-        },
-        value);
+    try {
+      std::visit(
+          [&](const auto& v) {
+            out = detail::write_variant_alternative<Char>(out, v);
+          },
+          value);
+    } catch (const std::bad_variant_access&) {
+      detail::write<Char>(out, "valueless by exception");
+    }
     *out++ = ')';
     return out;
   }
 };
 FMT_END_NAMESPACE
+#endif  // __cpp_lib_variant
+
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename Char> struct formatter<std::error_code, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write_bytes(out, ec.category().name(), format_specs<Char>());
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, ec.value());
+    return out;
+  }
+};
+
+FMT_MODULE_EXPORT
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    typename std::enable_if<std::is_base_of<std::exception, T>::value>::type> {
+ private:
+  bool with_typename_ = false;
+
+ public:
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (*it == 't') {
+      ++it;
+      with_typename_ = true;
+    }
+    return it;
+  }
+
+  template <typename OutputIt>
+  auto format(const std::exception& ex,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    format_specs<Char> spec;
+    auto out = ctx.out();
+    if (!with_typename_)
+      return detail::write_bytes(out, string_view(ex.what()), spec);
+
+    const std::type_info& ti = typeid(ex);
+#ifdef FMT_HAS_ABI_CXA_DEMANGLE
+    int status = 0;
+    std::size_t size = 0;
+    std::unique_ptr<char, decltype(&std::free)> demangled_name_ptr(
+        abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
+
+    string_view demangled_name_view;
+    if (demangled_name_ptr) {
+      demangled_name_view = demangled_name_ptr.get();
+
+      // Normalization of stdlib inline namespace names.
+      // libc++ inline namespaces.
+      //  std::__1::*       -> std::*
+      //  std::__1::__fs::* -> std::*
+      // libstdc++ inline namespaces.
+      //  std::__cxx11::*             -> std::*
+      //  std::filesystem::__cxx11::* -> std::filesystem::*
+      if (demangled_name_view.starts_with("std::")) {
+        char* begin = demangled_name_ptr.get();
+        char* to = begin + 5;  // std::
+        for (char *from = to, *end = begin + demangled_name_view.size();
+             from < end;) {
+          // This is safe, because demangled_name is NUL-terminated.
+          if (from[0] == '_' && from[1] == '_') {
+            char* next = from + 1;
+            while (next < end && *next != ':') next++;
+            if (next[0] == ':' && next[1] == ':') {
+              from = next + 2;
+              continue;
+            }
+          }
+          *to++ = *from++;
+        }
+        demangled_name_view = {begin, detail::to_unsigned(to - begin)};
+      }
+    } else {
+      demangled_name_view = string_view(ti.name());
+    }
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#elif FMT_MSC_VERSION
+    string_view demangled_name_view(ti.name());
+    if (demangled_name_view.starts_with("class "))
+      demangled_name_view.remove_prefix(6);
+    else if (demangled_name_view.starts_with("struct "))
+      demangled_name_view.remove_prefix(7);
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#else
+    out = detail::write_bytes(out, string_view(ti.name()), spec);
 #endif
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, Char(' '));
+    out = detail::write_bytes(out, string_view(ex.what()), spec);
+
+    return out;
+  }
+};
+FMT_END_NAMESPACE
 
 #endif  // FMT_STD_H_

include/fmt/xchar.h

@@ -12,13 +12,32 @@
 
 #include "format.h"
 
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#  include <locale>
+#endif
+
 FMT_BEGIN_NAMESPACE
 namespace detail {
+
 template <typename T>
 using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
-}
 
-FMT_MODULE_EXPORT_BEGIN
+inline auto write_loc(std::back_insert_iterator<detail::buffer<wchar_t>> out,
+                      loc_value value, const format_specs<wchar_t>& specs,
+                      locale_ref loc) -> bool {
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+  auto& numpunct =
+      std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
+  auto separator = std::wstring();
+  auto grouping = numpunct.grouping();
+  if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
+  return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
+#endif
+  return false;
+}
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
 
 using wstring_view = basic_string_view<wchar_t>;
 using wformat_parse_context = basic_format_parse_context<wchar_t>;
@@ -33,7 +52,9 @@ inline auto runtime(wstring_view s) -> wstring_view { return s; }
 #else
 template <typename... Args>
 using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
-inline auto runtime(wstring_view s) -> basic_runtime<wchar_t> { return {{s}}; }
+inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
+  return {{s}};
+}
 #endif
 
 template <> struct is_char<wchar_t> : std::true_type {};
@@ -126,7 +147,7 @@ auto vformat_to(OutputIt out, const S& format_str,
     -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, detail::to_string_view(format_str), args);
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 template <typename OutputIt, typename S, typename... Args,
@@ -149,7 +170,7 @@ inline auto vformat_to(
   auto&& buf = detail::get_buffer<Char>(out);
   vformat_to(buf, detail::to_string_view(format_str), args,
              detail::locale_ref(loc));
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 template <
@@ -160,7 +181,7 @@ template <
 inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
                       Args&&... args) ->
     typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, loc, to_string_view(format_str),
+  return vformat_to(out, loc, detail::to_string_view(format_str),
                     fmt::make_format_args<buffer_context<Char>>(args...));
 }
 
@@ -217,13 +238,22 @@ template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
   return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
 }
 
+template <typename... T>
+void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
+  return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
 /**
   Converts *value* to ``std::wstring`` using the default format for type *T*.
  */
 template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
   return format(FMT_STRING(L"{}"), value);
 }
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_XCHAR_H_

src/fmt.cc

@@ -1,49 +1,44 @@
 module;
-#ifndef __cpp_modules
-#  error Module not supported.
-#endif
-
-// put all implementation-provided headers into the global module fragment
-// to prevent attachment to this module
-#if !defined(_CRT_SECURE_NO_WARNINGS) && defined(_MSC_VER)
-#  define _CRT_SECURE_NO_WARNINGS
-#endif
-#if !defined(WIN32_LEAN_AND_MEAN) && defined(_WIN32)
-#  define WIN32_LEAN_AND_MEAN
-#endif
 
+// Put all implementation-provided headers into the global module fragment
+// to prevent attachment to this module.
 #include <algorithm>
-#include <cctype>
 #include <cerrno>
 #include <chrono>
 #include <climits>
-#include <clocale>
 #include <cmath>
-#include <cstdarg>
 #include <cstddef>
 #include <cstdint>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <ctime>
-#include <cwchar>
 #include <exception>
+#include <filesystem>
+#include <fstream>
 #include <functional>
 #include <iterator>
 #include <limits>
 #include <locale>
 #include <memory>
+#include <optional>
 #include <ostream>
-#include <sstream>
 #include <stdexcept>
 #include <string>
 #include <string_view>
 #include <system_error>
+#include <thread>
 #include <type_traits>
+#include <typeinfo>
 #include <utility>
+#include <variant>
 #include <vector>
+#include <version>
 
-#if _MSC_VER
+#if __has_include(<cxxabi.h>)
+#  include <cxxabi.h>
+#endif
+#if defined(_MSC_VER) || defined(__MINGW32__)
 #  include <intrin.h>
 #endif
 #if defined __APPLE__ || defined(__FreeBSD__)
@@ -65,22 +60,38 @@ module;
 #  endif
 #endif
 #ifdef _WIN32
+#  if defined(__GLIBCXX__)
+#    include <ext/stdio_filebuf.h>
+#    include <ext/stdio_sync_filebuf.h>
+#  elif defined(_LIBCPP_VERSION)
+#    include <__std_stream>
+#  endif
+#  define WIN32_LEAN_AND_MEAN
 #  include <windows.h>
 #endif
 
 export module fmt;
 
 #define FMT_MODULE_EXPORT export
-#define FMT_MODULE_EXPORT_BEGIN export {
-#define FMT_MODULE_EXPORT_END }
+#define FMT_BEGIN_EXPORT export {
+#define FMT_END_EXPORT }
 #define FMT_BEGIN_DETAIL_NAMESPACE \
   }                                \
   namespace detail {
 #define FMT_END_DETAIL_NAMESPACE \
   }                              \
   export {
-// all library-provided declarations and definitions
-// must be in the module purview to be exported
+// If you define FMT_ATTACH_TO_GLOBAL_MODULE
+//  - all declarations are detached from module 'fmt'
+//  - the module behaves like a traditional static library, too
+//  - all library symbols are mangled traditionally
+//  - you can mix TUs with either importing or #including the {fmt} API
+#ifdef FMT_ATTACH_TO_GLOBAL_MODULE
+extern "C++" {
+#endif
+
+// All library-provided declarations and definitions must be in the module
+// purview to be exported.
 #include "fmt/args.h"
 #include "fmt/chrono.h"
 #include "fmt/color.h"
@@ -88,11 +99,17 @@ export module fmt;
 #include "fmt/format.h"
 #include "fmt/os.h"
 #include "fmt/printf.h"
+#include "fmt/std.h"
 #include "fmt/xchar.h"
 
+
+#ifdef FMT_ATTACH_TO_GLOBAL_MODULE
+}
+#endif
+
 // gcc doesn't yet implement private module fragments
 #if !FMT_GCC_VERSION
-module : private;
+module :private;
 #endif
 
 #include "format.cc"

src/format.cc

@@ -28,12 +28,8 @@ template FMT_API auto decimal_point_impl(locale_ref) -> char;
 
 template FMT_API void 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 vformat_to(buffer<char>&, string_view,
-                                 basic_format_args<FMT_BUFFER_CONTEXT(char)>,
-                                 locale_ref);
+                                 typename vformat_args<>::type, locale_ref);
 
 // Explicit instantiations for wchar_t.
 

src/os.cc

@@ -72,34 +72,6 @@ inline std::size_t convert_rwcount(std::size_t count) { return count; }
 FMT_BEGIN_NAMESPACE
 
 #ifdef _WIN32
-detail::utf16_to_utf8::utf16_to_utf8(basic_string_view<wchar_t> s) {
-  if (int error_code = convert(s)) {
-    FMT_THROW(windows_error(error_code,
-                            "cannot convert string from UTF-16 to UTF-8"));
-  }
-}
-
-int detail::utf16_to_utf8::convert(basic_string_view<wchar_t> s) {
-  if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
-  int s_size = static_cast<int>(s.size());
-  if (s_size == 0) {
-    // WideCharToMultiByte does not support zero length, handle separately.
-    buffer_.resize(1);
-    buffer_[0] = 0;
-    return 0;
-  }
-
-  int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, nullptr, 0,
-                                   nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_.resize(length + 1);
-  length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
-                               length, nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_[length] = 0;
-  return 0;
-}
-
 namespace detail {
 
 class system_message {
@@ -140,8 +112,8 @@ class utf8_system_category final : public std::error_category {
   std::string message(int error_code) const override {
     system_message msg(error_code);
     if (msg) {
-      utf16_to_utf8 utf8_message;
-      if (utf8_message.convert(msg) == ERROR_SUCCESS) {
+      unicode_to_utf8<wchar_t> utf8_message;
+      if (utf8_message.convert(msg)) {
         return utf8_message.str();
       }
     }
@@ -167,9 +139,10 @@ void detail::format_windows_error(detail::buffer<char>& out, int error_code,
   FMT_TRY {
     system_message msg(error_code);
     if (msg) {
-      utf16_to_utf8 utf8_message;
-      if (utf8_message.convert(msg) == ERROR_SUCCESS) {
-        fmt::format_to(buffer_appender<char>(out), "{}: {}", message, utf8_message);
+      unicode_to_utf8<wchar_t> utf8_message;
+      if (utf8_message.convert(msg)) {
+        fmt::format_to(buffer_appender<char>(out), FMT_STRING("{}: {}"),
+                       message, string_view(utf8_message));
         return;
       }
     }
@@ -192,37 +165,47 @@ buffered_file::buffered_file(cstring_view filename, cstring_view mode) {
   FMT_RETRY_VAL(file_, FMT_SYSTEM(fopen(filename.c_str(), mode.c_str())),
                 nullptr);
   if (!file_)
-    FMT_THROW(system_error(errno, "cannot open file {}", filename.c_str()));
+    FMT_THROW(system_error(errno, FMT_STRING("cannot open file {}"),
+                           filename.c_str()));
 }
 
 void buffered_file::close() {
   if (!file_) return;
   int result = FMT_SYSTEM(fclose(file_));
   file_ = nullptr;
-  if (result != 0) FMT_THROW(system_error(errno, "cannot close file"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot close file")));
 }
 
 int buffered_file::descriptor() const {
+#ifdef fileno  // fileno is a macro on OpenBSD so we cannot use FMT_POSIX_CALL.
+  int fd = fileno(file_);
+#else
   int fd = FMT_POSIX_CALL(fileno(file_));
-  if (fd == -1) FMT_THROW(system_error(errno, "cannot get file descriptor"));
+#endif
+  if (fd == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get file descriptor")));
   return fd;
 }
 
 #if FMT_USE_FCNTL
-file::file(cstring_view path, int oflag) {
 #  ifdef _WIN32
-  using mode_t = int;
+using mode_t = int;
 #  endif
-  constexpr mode_t mode =
-      S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
+constexpr mode_t default_open_mode =
+    S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
+
+file::file(cstring_view path, int oflag) {
 #  if defined(_WIN32) && !defined(__MINGW32__)
   fd_ = -1;
-  FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));
+  auto converted = detail::utf8_to_utf16(string_view(path.c_str()));
+  *this = file::open_windows_file(converted.c_str(), oflag);
 #  else
-  FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, mode)));
-#  endif
+  FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, default_open_mode)));
   if (fd_ == -1)
-    FMT_THROW(system_error(errno, "cannot open file {}", path.c_str()));
+    FMT_THROW(
+        system_error(errno, FMT_STRING("cannot open file {}"), path.c_str()));
+#  endif
 }
 
 file::~file() noexcept {
@@ -238,7 +221,8 @@ void file::close() {
   // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
   int result = FMT_POSIX_CALL(close(fd_));
   fd_ = -1;
-  if (result != 0) FMT_THROW(system_error(errno, "cannot close file"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot close file")));
 }
 
 long long file::size() const {
@@ -260,7 +244,7 @@ long long file::size() const {
   using Stat = struct stat;
   Stat file_stat = Stat();
   if (FMT_POSIX_CALL(fstat(fd_, &file_stat)) == -1)
-    FMT_THROW(system_error(errno, "cannot get file attributes"));
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get file attributes")));
   static_assert(sizeof(long long) >= sizeof(file_stat.st_size),
                 "return type of file::size is not large enough");
   return file_stat.st_size;
@@ -270,14 +254,16 @@ long long file::size() const {
 std::size_t file::read(void* buffer, std::size_t count) {
   rwresult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
-  if (result < 0) FMT_THROW(system_error(errno, "cannot read from file"));
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot read from file")));
   return detail::to_unsigned(result);
 }
 
 std::size_t file::write(const void* buffer, std::size_t count) {
   rwresult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
-  if (result < 0) FMT_THROW(system_error(errno, "cannot write to file"));
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
   return detail::to_unsigned(result);
 }
 
@@ -286,7 +272,8 @@ file file::dup(int fd) {
   // http://pubs.opengroup.org/onlinepubs/009695399/functions/dup.html
   int new_fd = FMT_POSIX_CALL(dup(fd));
   if (new_fd == -1)
-    FMT_THROW(system_error(errno, "cannot duplicate file descriptor {}", fd));
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot duplicate file descriptor {}"), fd));
   return file(new_fd);
 }
 
@@ -294,8 +281,9 @@ void file::dup2(int fd) {
   int result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(dup2(fd_, fd)));
   if (result == -1) {
-    FMT_THROW(system_error(errno, "cannot duplicate file descriptor {} to {}",
-                           fd_, fd));
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot duplicate file descriptor {} to {}"), fd_,
+        fd));
   }
 }
 
@@ -320,7 +308,8 @@ void file::pipe(file& read_end, file& write_end) {
   // http://pubs.opengroup.org/onlinepubs/009696799/functions/pipe.html
   int result = FMT_POSIX_CALL(pipe(fds));
 #  endif
-  if (result != 0) FMT_THROW(system_error(errno, "cannot create pipe"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot create pipe")));
   // The following assignments don't throw because read_fd and write_fd
   // are closed.
   read_end = file(fds[0]);
@@ -334,28 +323,68 @@ buffered_file file::fdopen(const char* mode) {
 #  else
   FILE* f = FMT_POSIX_CALL(fdopen(fd_, mode));
 #  endif
-  if (!f)
-    FMT_THROW(
-        system_error(errno, "cannot associate stream with file descriptor"));
+  if (!f) {
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot associate stream with file descriptor")));
+  }
   buffered_file bf(f);
   fd_ = -1;
   return bf;
 }
 
+#  if defined(_WIN32) && !defined(__MINGW32__)
+file file::open_windows_file(wcstring_view path, int oflag) {
+  int fd = -1;
+  auto err = _wsopen_s(&fd, path.c_str(), oflag, _SH_DENYNO, default_open_mode);
+  if (fd == -1) {
+    FMT_THROW(
+        system_error(err, FMT_STRING("cannot open file {}"),
+                     detail::unicode_to_utf8<wchar_t>(path.c_str()).c_str()));
+  }
+  return file(fd);
+}
+#  endif
+
+#  if !defined(__MSDOS__)
 long getpagesize() {
-#  ifdef _WIN32
+#    ifdef _WIN32
   SYSTEM_INFO si;
   GetSystemInfo(&si);
   return si.dwPageSize;
-#  else
+#    else
   long size = FMT_POSIX_CALL(sysconf(_SC_PAGESIZE));
-  if (size < 0) FMT_THROW(system_error(errno, "cannot get memory page size"));
+  if (size < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get memory page size")));
   return size;
-#  endif
+#    endif
 }
+#  endif
 
-FMT_API void ostream::grow(size_t) {
+namespace detail {
+
+void file_buffer::grow(size_t) {
   if (this->size() == this->capacity()) flush();
 }
+
+file_buffer::file_buffer(cstring_view path,
+                         const detail::ostream_params& params)
+    : file_(path, params.oflag) {
+  set(new char[params.buffer_size], params.buffer_size);
+}
+
+file_buffer::file_buffer(file_buffer&& other)
+    : detail::buffer<char>(other.data(), other.size(), other.capacity()),
+      file_(std::move(other.file_)) {
+  other.clear();
+  other.set(nullptr, 0);
+}
+
+file_buffer::~file_buffer() {
+  flush();
+  delete[] data();
+}
+}  // namespace detail
+
+ostream::~ostream() = default;
 #endif  // FMT_USE_FCNTL
 FMT_END_NAMESPACE

support/Vagrantfile

@@ -13,8 +13,8 @@ Vagrant.configure("2") do |config|
   config.vm.provision "shell", inline: <<-SHELL
     apt-get update
     apt-get install -y g++ make wget git
-    wget -q https://github.com/Kitware/CMake/releases/download/v3.14.4/cmake-3.14.4-Linux-x86_64.tar.gz
-    tar xzf cmake-3.14.4-Linux-x86_64.tar.gz
-    ln -s `pwd`/cmake-3.14.4-Linux-x86_64/bin/cmake /usr/local/bin
+    wget -q https://github.com/Kitware/CMake/releases/download/v3.26.0/cmake-3.26.0-Linux-x86_64.tar.gz
+    tar xzf cmake-3.26.0-Linux-x86_64.tar.gz
+    ln -s `pwd`/cmake-3.26.0-Linux-x86_64/bin/cmake /usr/local/bin
   SHELL
 end

support/bazel/.bazelrc

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

support/bazel/.bazelversion

@@ -1 +1 @@
-5.1.1
+6.1.2

support/bazel/BUILD.bazel

@@ -11,8 +11,8 @@ cc_library(
         "include/fmt/color.h",
         "include/fmt/compile.h",
         "include/fmt/core.h",
-        "include/fmt/format-inl.h",
         "include/fmt/format.h",
+        "include/fmt/format-inl.h",
         "include/fmt/os.h",
         "include/fmt/ostream.h",
         "include/fmt/printf.h",
@@ -21,7 +21,7 @@ cc_library(
         "include/fmt/xchar.h",
     ],
     includes = [
-        "include",        
+        "include",
     ],
     strip_include_prefix = "include",
     visibility = ["//visibility:public"],

support/bazel/README.md

@@ -1,6 +1,6 @@
 # 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}). 
+To get [Bazel](https://bazel.build/) working with {fmt} you can copy the files `BUILD.bazel`, `WORKSPACE.bazel`, 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
 
@@ -37,7 +37,6 @@ git_repository(
     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",
@@ -47,7 +46,6 @@ git_repository(
     # 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",
@@ -55,7 +53,7 @@ git_repository(
 )
 ```
 
-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. 
+In the *WORKSPACE* file, the {fmt} GitHub repository is fetched. Using the attribute `patch_cmds` the  files `BUILD.bazel`, `WORKSPACE.bazel`, and `.bazelversion` are moved to the root of the {fmt} repository. This way the {fmt} repository is recognized as a bazelized workspace. 
 
 *BUILD.bazel*:
 
@@ -71,3 +69,6 @@ The *BUILD* file defines a binary named `Demo` that has a dependency to {fmt}.
 
 To execute the binary you can run `bazel run //:Demo`.
 
+# Using Bzlmod
+
+The [Bazel Central Registry](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/fmt) also provides support for {fmt}.

support/build.gradle

@@ -11,7 +11,7 @@ buildscript {
         // https://developer.android.com/studio/releases/gradle-plugin#updating-gradle
         //
         // Notice that 4.0.0 here is the version of [Android Gradle Plugin]
-        // Accroding to URL above you will need Gradle 6.1 or higher
+        // According to URL above you will need Gradle 6.1 or higher
         //
         classpath "com.android.tools.build:gradle:4.1.1"
     }

support/cmake/cxx14.cmake

@@ -1,54 +0,0 @@
-# C++14 feature support detection
-
-include(CheckCXXCompilerFlag)
-function (fmt_check_cxx_compiler_flag flag result)
-  if (NOT MSVC)
-    check_cxx_compiler_flag("${flag}" ${result})
-  endif ()
-endfunction ()
-
-if (NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 11)
-endif()
-message(STATUS "CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
-
-if (CMAKE_CXX_STANDARD EQUAL 20)
-  fmt_check_cxx_compiler_flag(-std=c++20 has_std_20_flag)
-  fmt_check_cxx_compiler_flag(-std=c++2a has_std_2a_flag)
-
-  if (has_std_20_flag)
-    set(CXX_STANDARD_FLAG -std=c++20)
-  elseif (has_std_2a_flag)
-    set(CXX_STANDARD_FLAG -std=c++2a)
-  endif ()
-
-elseif (CMAKE_CXX_STANDARD EQUAL 17)
-  fmt_check_cxx_compiler_flag(-std=c++17 has_std_17_flag)
-  fmt_check_cxx_compiler_flag(-std=c++1z has_std_1z_flag)
-
-  if (has_std_17_flag)
-    set(CXX_STANDARD_FLAG -std=c++17)
-  elseif (has_std_1z_flag)
-    set(CXX_STANDARD_FLAG -std=c++1z)
-  endif ()
-
-elseif (CMAKE_CXX_STANDARD EQUAL 14)
-  fmt_check_cxx_compiler_flag(-std=c++14 has_std_14_flag)
-  fmt_check_cxx_compiler_flag(-std=c++1y has_std_1y_flag)
-
-  if (has_std_14_flag)
-    set(CXX_STANDARD_FLAG -std=c++14)
-  elseif (has_std_1y_flag)
-    set(CXX_STANDARD_FLAG -std=c++1y)
-  endif ()
-
-elseif (CMAKE_CXX_STANDARD EQUAL 11)
-  fmt_check_cxx_compiler_flag(-std=c++11 has_std_11_flag)
-  fmt_check_cxx_compiler_flag(-std=c++0x has_std_0x_flag)
-
-  if (has_std_11_flag)
-    set(CXX_STANDARD_FLAG -std=c++11)
-  elseif (has_std_0x_flag)
-    set(CXX_STANDARD_FLAG -std=c++0x)
-  endif ()
-endif ()

test/CMakeLists.txt

@@ -1,5 +1,7 @@
 add_subdirectory(gtest)
 
+include(CheckSymbolExists)
+
 set(TEST_MAIN_SRC test-main.cc gtest-extra.cc gtest-extra.h util.cc)
 add_library(test-main STATIC ${TEST_MAIN_SRC})
 target_include_directories(test-main PUBLIC
@@ -35,7 +37,7 @@ function(add_fmt_test name)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wno-weak-vtables)
     endif ()
   elseif (ADD_FMT_TEST_MODULE)
-    set(libs gtest test-module)
+    set(libs test-main test-module)
     set_source_files_properties(${name}.cc PROPERTIES OBJECT_DEPENDS test-module)
   else ()
     set(libs test-main fmt)
@@ -53,6 +55,10 @@ function(add_fmt_test name)
   add_test(NAME ${name} COMMAND ${name})
 endfunction()
 
+if (FMT_MODULE)
+  return ()
+endif ()
+
 add_fmt_test(args-test)
 add_fmt_test(assert-test)
 add_fmt_test(chrono-test)
@@ -75,7 +81,13 @@ if (MSVC)
 endif()
 add_fmt_test(printf-test)
 add_fmt_test(ranges-test ranges-odr-test.cc)
+
 add_fmt_test(scan-test)
+check_symbol_exists(strptime "time.h" HAVE_STRPTIME)
+if (HAVE_STRPTIME)
+  target_compile_definitions(scan-test PRIVATE FMT_HAVE_STRPTIME)
+endif ()
+
 add_fmt_test(std-test)
 try_compile(compile_result_unused
             ${CMAKE_CURRENT_BINARY_DIR}
@@ -94,13 +106,13 @@ add_fmt_test(enforce-checks-test)
 target_compile_definitions(enforce-checks-test PRIVATE
                            -DFMT_ENFORCE_COMPILE_STRING)
 
-if (FMT_CAN_MODULE)
+if (FMT_MODULE)
   # The tests need {fmt} to be compiled as traditional library
   # because of visibility of implementation details.
   # If module support is present the module tests require a
   # test-only module to be built from {fmt}
   add_library(test-module OBJECT ${CMAKE_SOURCE_DIR}/src/fmt.cc)
-  target_compile_features(test-module PUBLIC ${FMT_REQUIRED_FEATURES})
+  target_compile_features(test-module PUBLIC cxx_std_11)
   target_include_directories(test-module PUBLIC
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
   enable_module(test-module)

test/add-subdirectory-test/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.18)
+cmake_minimum_required(VERSION 3.8...3.25)
 
 project(fmt-test CXX)
 

test/args-test.cc

@@ -44,7 +44,7 @@ template <> struct formatter<custom_type> {
 
   template <typename FormatContext>
   auto format(const custom_type& p, FormatContext& ctx) -> decltype(ctx.out()) {
-    return format_to(ctx.out(), "cust={}", p.i);
+    return fmt::format_to(ctx.out(), "cust={}", p.i);
   }
 };
 FMT_END_NAMESPACE

test/chrono-test.cc

@@ -7,6 +7,7 @@
 
 #include "fmt/chrono.h"
 
+#include <algorithm>
 #include <ctime>
 #include <vector>
 
@@ -14,9 +15,15 @@
 #include "util.h"         // get_locale
 
 using fmt::runtime;
-
 using testing::Contains;
 
+#if defined(__MINGW32__) && !defined(_UCRT)
+// Only C89 conversion specifiers when using MSVCRT instead of UCRT
+#  define FMT_HAS_C99_STRFTIME 0
+#else
+#  define FMT_HAS_C99_STRFTIME 1
+#endif
+
 auto make_tm() -> std::tm {
   auto time = std::tm();
   time.tm_mday = 1;
@@ -122,7 +129,7 @@ TEST(chrono_test, format_tm) {
       make_tm(2000, 1, 3, 12, 14, 16)     // W1
   };
 
-#if defined(__MINGW32__) && !defined(_UCRT)
+#if !FMT_HAS_C99_STRFTIME
   GTEST_SKIP() << "Skip the rest of this test because it relies on strftime() "
                   "conforming to C99, but on this platform, MINGW + MSVCRT, "
                   "the function conforms only to C89.";
@@ -234,32 +241,135 @@ auto equal(const std::tm& lhs, const std::tm& rhs) -> bool {
          lhs.tm_isdst == rhs.tm_isdst;
 }
 
-TEST(chrono_test, localtime) {
-  auto t = std::time(nullptr);
-  auto tm = *std::localtime(&t);
-  EXPECT_TRUE(equal(tm, fmt::localtime(t)));
-}
-
 TEST(chrono_test, gmtime) {
   auto t = std::time(nullptr);
   auto tm = *std::gmtime(&t);
   EXPECT_TRUE(equal(tm, fmt::gmtime(t)));
 }
 
-template <typename TimePoint> auto strftime_full(TimePoint tp) -> std::string {
+template <typename TimePoint>
+auto strftime_full_utc(TimePoint tp) -> std::string {
   auto t = std::chrono::system_clock::to_time_t(tp);
+  auto tm = *std::gmtime(&t);
+  return system_strftime("%Y-%m-%d %H:%M:%S", &tm);
+}
+
+TEST(chrono_test, system_clock_time_point) {
+  auto t1 = std::chrono::time_point_cast<std::chrono::seconds>(
+      std::chrono::system_clock::now());
+  EXPECT_EQ(strftime_full_utc(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
+  EXPECT_EQ(strftime_full_utc(t1), fmt::format("{}", t1));
+  EXPECT_EQ(strftime_full_utc(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_full_utc(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"};
+#ifndef _WIN32
+  // Disabled on Windows because these formats are not consistent among
+  // platforms.
+  spec_list.insert(spec_list.end(), {"%c", "%Ec", "%r"});
+#elif !FMT_HAS_C99_STRFTIME
+  // Only C89 conversion specifiers when using MSVCRT instead of UCRT
+  spec_list = {"%%", "%Y", "%y", "%b", "%B", "%m", "%U", "%W", "%j", "%d",
+               "%a", "%A", "%w", "%H", "%I", "%M", "%S", "%x", "%X", "%p"};
+#endif
+  spec_list.push_back("%Y-%m-%d %H:%M:%S");
+
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&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));
+  }
+
+  // Timezone formatters tests makes sense for localtime.
+#if FMT_HAS_C99_STRFTIME
+  spec_list = {"%z", "%Z"};
+#else
+  spec_list = {"%Z"};
+#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), tm));
+
+    if (spec == "%z") {
+      sys_output.insert(sys_output.end() - 2, 1, ':');
+      EXPECT_EQ(sys_output, fmt::format("{:%Ez}", tm));
+      EXPECT_EQ(sys_output, fmt::format("{:%Oz}", tm));
+    }
+  }
+
+  // Separate tests for UTC, since std::time_put can use local time and ignoring
+  // the timezone in std::tm (if it presents on platform).
+  if (fmt::detail::has_member_data_tm_zone<std::tm>::value) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&t);
+
+    std::vector<std::string> tz_names = {"GMT", "UTC"};
+    EXPECT_THAT(tz_names, Contains(fmt::format("{:%Z}", t1)));
+    EXPECT_THAT(tz_names, Contains(fmt::format("{:%Z}", tm)));
+  }
+
+  if (fmt::detail::has_member_data_tm_gmtoff<std::tm>::value) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&t);
+
+    EXPECT_EQ("+0000", fmt::format("{:%z}", t1));
+    EXPECT_EQ("+0000", fmt::format("{:%z}", tm));
+
+    EXPECT_EQ("+00:00", fmt::format("{:%Ez}", t1));
+    EXPECT_EQ("+00:00", fmt::format("{:%Ez}", tm));
+
+    EXPECT_EQ("+00:00", fmt::format("{:%Oz}", t1));
+    EXPECT_EQ("+00:00", fmt::format("{:%Oz}", tm));
+  }
+}
+
+#if FMT_USE_LOCAL_TIME
+
+TEST(chrono_test, localtime) {
+  auto t = std::time(nullptr);
+  auto tm = *std::localtime(&t);
+  EXPECT_TRUE(equal(tm, fmt::localtime(t)));
+}
+
+template <typename Duration>
+auto strftime_full_local(std::chrono::local_time<Duration> tp) -> std::string {
+  auto t = std::chrono::system_clock::to_time_t(
+      std::chrono::current_zone()->to_sys(tp));
   auto tm = *std::localtime(&t);
   return system_strftime("%Y-%m-%d %H:%M:%S", &tm);
 }
 
-TEST(chrono_test, time_point) {
-  auto t1 = std::chrono::system_clock::now();
-  EXPECT_EQ(strftime_full(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", 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_full(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
+TEST(chrono_test, local_system_clock_time_point) {
+#  ifdef _WIN32
+  return;  // Not supported on Windows.
+#  endif
+  auto t1 = std::chrono::time_point_cast<std::chrono::seconds>(
+      std::chrono::current_zone()->to_local(std::chrono::system_clock::now()));
+  EXPECT_EQ(strftime_full_local(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
+  EXPECT_EQ(strftime_full_local(t1), fmt::format("{}", t1));
+  EXPECT_EQ(strftime_full_local(t1), fmt::format("{:}", t1));
+  using time_point = std::chrono::local_time<std::chrono::seconds>;
+  auto t2 = time_point(std::chrono::seconds(86400 + 42));
+  EXPECT_EQ(strftime_full_local(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
 
   std::vector<std::string> spec_list = {
       "%%",  "%n",  "%t",  "%Y",  "%EY", "%y",  "%Oy", "%Ey", "%C",
@@ -268,19 +378,20 @@ TEST(chrono_test, time_point) {
       "%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"};
-#ifndef _WIN32
+#  ifndef _WIN32
   // Disabled on Windows because these formats are not consistent among
   // platforms.
   spec_list.insert(spec_list.end(), {"%c", "%Ec", "%r"});
-#elif defined(__MINGW32__) && !defined(_UCRT)
+#  elif !FMT_HAS_C99_STRFTIME
   // Only C89 conversion specifiers when using MSVCRT instead of UCRT
   spec_list = {"%%", "%Y", "%y", "%b", "%B", "%m", "%U", "%W", "%j", "%d", "%a",
                "%A", "%w", "%H", "%I", "%M", "%S", "%x", "%X", "%p", "%Z"};
-#endif
+#  endif
   spec_list.push_back("%Y-%m-%d %H:%M:%S");
 
   for (const auto& spec : spec_list) {
-    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto t = std::chrono::system_clock::to_time_t(
+        std::chrono::current_zone()->to_sys(t1));
     auto tm = *std::localtime(&t);
 
     auto sys_output = system_strftime(spec, &tm);
@@ -289,8 +400,26 @@ TEST(chrono_test, time_point) {
     EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
     EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
   }
+
+  if (std::find(spec_list.cbegin(), spec_list.cend(), "%z") !=
+      spec_list.cend()) {
+    auto t = std::chrono::system_clock::to_time_t(
+        std::chrono::current_zone()->to_sys(t1));
+    auto tm = *std::localtime(&t);
+
+    auto sys_output = system_strftime("%z", &tm);
+    sys_output.insert(sys_output.end() - 2, 1, ':');
+
+    EXPECT_EQ(sys_output, fmt::format("{:%Ez}", t1));
+    EXPECT_EQ(sys_output, fmt::format("{:%Ez}", tm));
+
+    EXPECT_EQ(sys_output, fmt::format("{:%Oz}", t1));
+    EXPECT_EQ(sys_output, fmt::format("{:%Oz}", tm));
+  }
 }
 
+#endif  // FMT_USE_LOCAL_TIME
+
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
 
 TEST(chrono_test, format_default) {
@@ -335,7 +464,7 @@ TEST(chrono_test, format_default) {
       fmt::format("{}", std::chrono::duration<int, std::ratio<15, 4>>(42)));
 }
 
-TEST(chrono_test, align) {
+TEST(chrono_test, duration_align) {
   auto s = std::chrono::seconds(42);
   EXPECT_EQ("42s  ", fmt::format("{:5}", s));
   EXPECT_EQ("42s  ", fmt::format("{:{}}", s, 5));
@@ -351,6 +480,35 @@ TEST(chrono_test, align) {
             fmt::format("{:{}%H:%M:%S}", std::chrono::seconds(12345), 12));
 }
 
+TEST(chrono_test, tm_align) {
+  auto t = make_tm(1975, 12, 29, 12, 14, 16);
+  EXPECT_EQ("1975-12-29 12:14:16", fmt::format("{:%F %T}", t));
+  EXPECT_EQ("1975-12-29 12:14:16           ", fmt::format("{:30%F %T}", t));
+  EXPECT_EQ("1975-12-29 12:14:16           ", fmt::format("{:{}%F %T}", t, 30));
+  EXPECT_EQ("1975-12-29 12:14:16           ", fmt::format("{:<30%F %T}", t));
+  EXPECT_EQ("     1975-12-29 12:14:16      ", fmt::format("{:^30%F %T}", t));
+  EXPECT_EQ("           1975-12-29 12:14:16", fmt::format("{:>30%F %T}", t));
+
+  EXPECT_EQ("1975-12-29 12:14:16***********", fmt::format("{:*<30%F %T}", t));
+  EXPECT_EQ("*****1975-12-29 12:14:16******", fmt::format("{:*^30%F %T}", t));
+  EXPECT_EQ("***********1975-12-29 12:14:16", fmt::format("{:*>30%F %T}", t));
+}
+
+TEST(chrono_test, tp_align) {
+  auto tp = std::chrono::time_point_cast<std::chrono::microseconds>(
+      std::chrono::system_clock::from_time_t(0));
+  EXPECT_EQ("00:00.000000", fmt::format("{:%M:%S}", tp));
+  EXPECT_EQ("00:00.000000   ", fmt::format("{:15%M:%S}", tp));
+  EXPECT_EQ("00:00.000000   ", fmt::format("{:{}%M:%S}", tp, 15));
+  EXPECT_EQ("00:00.000000   ", fmt::format("{:<15%M:%S}", tp));
+  EXPECT_EQ(" 00:00.000000  ", fmt::format("{:^15%M:%S}", tp));
+  EXPECT_EQ("   00:00.000000", fmt::format("{:>15%M:%S}", tp));
+
+  EXPECT_EQ("00:00.000000***", fmt::format("{:*<15%M:%S}", tp));
+  EXPECT_EQ("*00:00.000000**", fmt::format("{:*^15%M:%S}", tp));
+  EXPECT_EQ("***00:00.000000", fmt::format("{:*>15%M:%S}", tp));
+}
+
 TEST(chrono_test, format_specs) {
   EXPECT_EQ("%", fmt::format("{:%%}", std::chrono::seconds(0)));
   EXPECT_EQ("\n", fmt::format("{:%n}", std::chrono::seconds(0)));
@@ -418,6 +576,10 @@ TEST(chrono_test, invalid_specs) {
                    "invalid format");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Oq}"), sec), fmt::format_error,
                    "invalid format");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:abc}"), sec), fmt::format_error,
+                   "invalid format");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.2f}"), sec), fmt::format_error,
+                   "invalid format");
 }
 
 auto format_tm(const std::tm& time, fmt::string_view spec,
@@ -465,7 +627,7 @@ TEST(chrono_test, format_default_fp) {
 
 TEST(chrono_test, format_precision) {
   EXPECT_THROW_MSG(
-      (void)fmt::format(runtime("{:.2}"), std::chrono::seconds(42)),
+      (void)fmt::format(runtime("{:.2%Q}"), std::chrono::seconds(42)),
       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)));
@@ -610,12 +772,28 @@ TEST(chrono_test, cpp20_duration_subsecond_support) {
   EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{-13420148734}),
             "-13.420148734");
   EXPECT_EQ(fmt::format("{:%S}", std::chrono::milliseconds{1234}), "01.234");
+  // Check subsecond presision modifier.
+  EXPECT_EQ(fmt::format("{:.6%S}", std::chrono::nanoseconds{1234}),
+            "00.000001");
+  EXPECT_EQ(fmt::format("{:.18%S}", std::chrono::nanoseconds{1234}),
+            "00.000001234000000000");
+  EXPECT_EQ(fmt::format("{:.{}%S}", std::chrono::nanoseconds{1234}, 6),
+            "00.000001");
+  EXPECT_EQ(fmt::format("{:.6%S}", std::chrono::milliseconds{1234}),
+            "01.234000");
+  EXPECT_EQ(fmt::format("{:.6%S}", std::chrono::milliseconds{-1234}),
+            "-01.234000");
+  EXPECT_EQ(fmt::format("{:.3%S}", std::chrono::seconds{1234}), "34.000");
+  EXPECT_EQ(fmt::format("{:.3%S}", std::chrono::hours{1234}), "00.000");
+  EXPECT_EQ(fmt::format("{:.5%S}", dms(1.234)), "00.00123");
+  EXPECT_EQ(fmt::format("{:.8%S}", dms(1.234)), "00.00123400");
   {
     // 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);
+    EXPECT_EQ(fmt::format("{:.6%H:%M:%S}", dur), "01:00:01.234000");
   }
   using nanoseconds_dbl = std::chrono::duration<double, std::nano>;
   EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{-123456789}), "-00.123456789");
@@ -629,15 +807,173 @@ TEST(chrono_test, cpp20_duration_subsecond_support) {
     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);
+    EXPECT_EQ(fmt::format("{:.3%H:%M:%S}", dur), "-00:01:39.123");
   }
   // 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");
-  EXPECT_EQ(fmt::format("{:%S}", std::chrono::duration<long long, std::ratio<1, 3>>(1)),
+  EXPECT_EQ(fmt::format("{:%S}",
+                        std::chrono::duration<long long, std::ratio<1, 3>>(1)),
             "00.333333");
-  EXPECT_EQ(fmt::format("{:%S}", std::chrono::duration<long long, std::ratio<1, 7>>(1)),
+  EXPECT_EQ(fmt::format("{:%S}",
+                        std::chrono::duration<long long, std::ratio<1, 7>>(1)),
             "00.142857");
+
+  EXPECT_EQ(
+      fmt::format("{:%S}",
+                  std::chrono::duration<signed char, std::ratio<1, 100>>(0x80)),
+      "-01.28");
+
+  EXPECT_EQ(
+      fmt::format("{:%M:%S}",
+                  std::chrono::duration<short, std::ratio<1, 100>>(0x8000)),
+      "-05:27.68");
+
+  // Check that floating point seconds with ratio<1,1> are printed.
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::duration<double>{1.5}),
+            "01.500000");
+  EXPECT_EQ(fmt::format("{:%M:%S}", std::chrono::duration<double>{-61.25}),
+            "-01:01.250000");
 }
 
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR
+
+// Disable the utc_clock test for windows, as the icu.dll used for tzdb
+// (time zone database) is not shipped with many windows versions.
+#if FMT_USE_UTC_TIME && !defined(_WIN32)
+TEST(chrono_test, utc_clock) {
+  auto t1 = std::chrono::system_clock::now();
+  auto t1_utc = std::chrono::utc_clock::from_sys(t1);
+  EXPECT_EQ(fmt::format("{:%Y-%m-%d %H:%M:%S}", t1),
+            fmt::format("{:%Y-%m-%d %H:%M:%S}", t1_utc));
+}
+#endif
+
+TEST(chrono_test, timestamps_sub_seconds) {
+  std::chrono::time_point<std::chrono::system_clock,
+                          std::chrono::duration<long long, std::ratio<1, 3>>>
+      t1(std::chrono::duration<long long, std::ratio<1, 3>>(4));
+
+  EXPECT_EQ(fmt::format("{:%S}", t1), "01.333333");
+
+  std::chrono::time_point<std::chrono::system_clock,
+                          std::chrono::duration<double, std::ratio<1, 3>>>
+      t2(std::chrono::duration<double, std::ratio<1, 3>>(4));
+
+  EXPECT_EQ(fmt::format("{:%S}", t2), "01.333333");
+
+  const std::chrono::time_point<std::chrono::system_clock, std::chrono::seconds>
+      t3(std::chrono::seconds(2));
+
+  EXPECT_EQ(fmt::format("{:%S}", t3), "02");
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::duration<double>>
+      t4(std::chrono::duration<double, std::ratio<1, 1>>(9.5));
+
+  EXPECT_EQ(fmt::format("{:%S}", t4), "09.500000");
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::duration<double>>
+      t5(std::chrono::duration<double, std::ratio<1, 1>>(9));
+
+  EXPECT_EQ(fmt::format("{:%S}", t5), "09");
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::milliseconds>
+      t6(std::chrono::seconds(1) + std::chrono::milliseconds(120));
+
+  EXPECT_EQ(fmt::format("{:%S}", t6), "01.120");
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::microseconds>
+      t7(std::chrono::microseconds(1234567));
+
+  EXPECT_EQ(fmt::format("{:%S}", t7), "01.234567");
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::nanoseconds>
+      t8(std::chrono::nanoseconds(123456789));
+
+  EXPECT_EQ(fmt::format("{:%S}", t8), "00.123456789");
+
+  const auto t9 = std::chrono::time_point_cast<std::chrono::nanoseconds>(
+      std::chrono::system_clock::now());
+  const auto t9_sec = std::chrono::time_point_cast<std::chrono::seconds>(t9);
+  auto t9_sub_sec_part = fmt::format("{0:09}", (t9 - t9_sec).count());
+
+  EXPECT_EQ(fmt::format("{}.{}", strftime_full_utc(t9_sec), t9_sub_sec_part),
+            fmt::format("{:%Y-%m-%d %H:%M:%S}", t9));
+  EXPECT_EQ(fmt::format("{}.{}", strftime_full_utc(t9_sec), t9_sub_sec_part),
+            fmt::format("{:%Y-%m-%d %T}", t9));
+
+  const std::chrono::time_point<std::chrono::system_clock,
+                                std::chrono::milliseconds>
+      t10(std::chrono::milliseconds(2000));
+
+  EXPECT_EQ(fmt::format("{:%S}", t10), "02.000");
+
+  {
+    const auto epoch = std::chrono::time_point<std::chrono::system_clock,
+                                               std::chrono::milliseconds>();
+    const auto d = std::chrono::milliseconds(250);
+
+    EXPECT_EQ("59.750", fmt::format("{:%S}", epoch - d));
+    EXPECT_EQ("00.000", fmt::format("{:%S}", epoch));
+    EXPECT_EQ("00.250", fmt::format("{:%S}", epoch + d));
+  }
+}
+
+TEST(chrono_test, glibc_extensions) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%0}"), std::chrono::seconds()),
+                   fmt::format_error, "invalid format");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%_}"), std::chrono::seconds()),
+                   fmt::format_error, "invalid format");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%-}"), std::chrono::seconds()),
+                   fmt::format_error, "invalid format");
+
+  {
+    const auto d = std::chrono::hours(1) + std::chrono::minutes(2) +
+                   std::chrono::seconds(3);
+
+    EXPECT_EQ(fmt::format("{:%I,%H,%M,%S}", d), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%0I,%0H,%0M,%0S}", d), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%_I,%_H,%_M,%_S}", d), " 1, 1, 2, 3");
+    EXPECT_EQ(fmt::format("{:%-I,%-H,%-M,%-S}", d), "1,1,2,3");
+
+    EXPECT_EQ(fmt::format("{:%OI,%OH,%OM,%OS}", d), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%0OI,%0OH,%0OM,%0OS}", d), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%_OI,%_OH,%_OM,%_OS}", d), " 1, 1, 2, 3");
+    EXPECT_EQ(fmt::format("{:%-OI,%-OH,%-OM,%-OS}", d), "1,1,2,3");
+  }
+
+  {
+    const auto tm = make_tm(1970, 1, 1, 1, 2, 3);
+    EXPECT_EQ(fmt::format("{:%I,%H,%M,%S}", tm), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%0I,%0H,%0M,%0S}", tm), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%_I,%_H,%_M,%_S}", tm), " 1, 1, 2, 3");
+    EXPECT_EQ(fmt::format("{:%-I,%-H,%-M,%-S}", tm), "1,1,2,3");
+
+    EXPECT_EQ(fmt::format("{:%OI,%OH,%OM,%OS}", tm), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%0OI,%0OH,%0OM,%0OS}", tm), "01,01,02,03");
+    EXPECT_EQ(fmt::format("{:%_OI,%_OH,%_OM,%_OS}", tm), " 1, 1, 2, 3");
+    EXPECT_EQ(fmt::format("{:%-OI,%-OH,%-OM,%-OS}", tm), "1,1,2,3");
+  }
+
+  {
+    const auto d = std::chrono::seconds(3) + std::chrono::milliseconds(140);
+    EXPECT_EQ(fmt::format("{:%S}", d), "03.140");
+    EXPECT_EQ(fmt::format("{:%0S}", d), "03.140");
+    EXPECT_EQ(fmt::format("{:%_S}", d), " 3.140");
+    EXPECT_EQ(fmt::format("{:%-S}", d), "3.140");
+  }
+
+  {
+    const auto d = std::chrono::duration<double>(3.14);
+    EXPECT_EQ(fmt::format("{:%S}", d), "03.140000");
+    EXPECT_EQ(fmt::format("{:%0S}", d), "03.140000");
+    EXPECT_EQ(fmt::format("{:%_S}", d), " 3.140000");
+    EXPECT_EQ(fmt::format("{:%-S}", d), "3.140000");
+  }
+}

test/compile-error-test/CMakeLists.txt

@@ -1,6 +1,6 @@
 # Test if compile errors are produced where necessary.
 
-cmake_minimum_required(VERSION 3.1...3.18)
+cmake_minimum_required(VERSION 3.8...3.25)
 project(compile-error-test CXX)
 
 set(fmt_headers "
@@ -64,7 +64,7 @@ function (run_tests)
   ")
 
   file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/CMakeLists.txt" "
-    cmake_minimum_required(VERSION 3.1...3.18)
+    cmake_minimum_required(VERSION 3.8...3.25)
     project(tests CXX)
     add_subdirectory(${FMT_DIR} fmt)
     ${cmake_targets}

test/compile-test.cc

@@ -304,8 +304,9 @@ TEST(compile_test, compile_format_string_literal) {
 //  (compiler file
 //  'D:\a\_work\1\s\src\vctools\Compiler\CxxFE\sl\p1\c\constexpr\constexpr.cpp',
 //  line 8635)
-#if ((FMT_CPLUSPLUS >= 202002L) &&                    \
-     (!FMT_MSC_VERSION || FMT_MSC_VERSION < 1930)) || \
+#if ((FMT_CPLUSPLUS >= 202002L) &&                           \
+     (!defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE > 9) && \
+     (!FMT_MSC_VERSION || FMT_MSC_VERSION < 1930)) ||        \
     (FMT_CPLUSPLUS >= 201709L && FMT_GCC_VERSION >= 1002)
 template <size_t max_string_length, typename Char = char> struct test_string {
   template <typename T> constexpr bool operator==(const T& rhs) const noexcept {

test/core-test.cc

@@ -9,9 +9,7 @@
 #include "test-assert.h"
 // clang-format on
 
-#define I 42  // simulate https://en.cppreference.com/w/c/numeric/complex/I
 #include "fmt/core.h"
-#undef I
 
 #include <algorithm>    // std::copy_n
 #include <climits>      // INT_MAX
@@ -72,6 +70,16 @@ TEST(string_view_test, compare) {
   EXPECT_LT(string_view("foo").compare(string_view("fop")), 0);
   EXPECT_GT(string_view("foo").compare(string_view("fo")), 0);
   EXPECT_LT(string_view("fo").compare(string_view("foo")), 0);
+
+  EXPECT_TRUE(string_view("foo").starts_with('f'));
+  EXPECT_FALSE(string_view("foo").starts_with('o'));
+  EXPECT_FALSE(string_view().starts_with('o'));
+
+  EXPECT_TRUE(string_view("foo").starts_with("fo"));
+  EXPECT_TRUE(string_view("foo").starts_with("foo"));
+  EXPECT_FALSE(string_view("foo").starts_with("fooo"));
+  EXPECT_FALSE(string_view().starts_with("fooo"));
+
   check_op<std::equal_to>();
   check_op<std::not_equal_to>();
   check_op<std::less>();
@@ -80,24 +88,6 @@ TEST(string_view_test, compare) {
   check_op<std::greater_equal>();
 }
 
-namespace test_ns {
-template <typename Char> class test_string {
- private:
-  std::basic_string<Char> s_;
-
- public:
-  test_string(const Char* s) : s_(s) {}
-  const Char* data() const { return s_.data(); }
-  size_t length() const { return s_.size(); }
-  operator const Char*() const { return s_.c_str(); }
-};
-
-template <typename Char>
-fmt::basic_string_view<Char> to_string_view(const test_string<Char>& s) {
-  return {s.data(), s.length()};
-}
-}  // namespace test_ns
-
 TEST(core_test, is_output_iterator) {
   EXPECT_TRUE((fmt::detail::is_output_iterator<char*, char>::value));
   EXPECT_FALSE((fmt::detail::is_output_iterator<const char*, char>::value));
@@ -151,7 +141,7 @@ TEST(buffer_test, indestructible) {
 }
 
 template <typename T> struct mock_buffer final : buffer<T> {
-  MOCK_METHOD1(do_grow, size_t(size_t capacity));
+  MOCK_METHOD(size_t, do_grow, (size_t));
 
   void grow(size_t capacity) override {
     this->set(this->data(), do_grow(capacity));
@@ -304,7 +294,7 @@ template <typename Char> struct formatter<test_struct, Char> {
     return ctx.begin();
   }
 
-  auto format(test_struct, format_context& ctx) -> decltype(ctx.out()) {
+  auto format(test_struct, format_context& ctx) const -> decltype(ctx.out()) {
     auto test = string_view("test");
     return std::copy_n(test.data(), test.size(), ctx.out());
   }
@@ -318,7 +308,7 @@ TEST(arg_test, format_args) {
 
 TEST(arg_test, make_value_with_custom_context) {
   auto t = test_struct();
-  fmt::detail::value<custom_context> arg(
+  auto arg = fmt::detail::value<custom_context>(
       fmt::detail::arg_mapper<custom_context>().map(t));
   auto ctx = custom_context();
   auto parse_ctx = fmt::format_parse_context("");
@@ -337,12 +327,12 @@ template <typename T> struct mock_visitor {
     ON_CALL(*this, visit(_)).WillByDefault(Return(test_result()));
   }
 
-  MOCK_METHOD1_T(visit, test_result(T value));
-  MOCK_METHOD0_T(unexpected, void());
+  MOCK_METHOD(test_result, visit, (T));
+  MOCK_METHOD(void, unexpected, ());
 
-  test_result operator()(T value) { return visit(value); }
+  auto operator()(T value) -> test_result { return visit(value); }
 
-  template <typename U> test_result operator()(U) {
+  template <typename U> auto operator()(U) -> test_result {
     unexpected();
     return test_result();
   }
@@ -394,13 +384,13 @@ using test_types =
 TYPED_TEST_SUITE(numeric_arg_test, test_types);
 
 template <typename T, fmt::enable_if_t<std::is_integral<T>::value, int> = 0>
-T test_value() {
+auto test_value() -> T {
   return static_cast<T>(42);
 }
 
 template <typename T,
           fmt::enable_if_t<std::is_floating_point<T>::value, int> = 0>
-T test_value() {
+auto test_value() -> T {
   return static_cast<T>(4.2);
 }
 
@@ -443,8 +433,8 @@ TEST(arg_test, pointer_arg) {
 }
 
 struct check_custom {
-  test_result operator()(
-      fmt::basic_format_arg<fmt::format_context>::handle h) const {
+  auto operator()(fmt::basic_format_arg<fmt::format_context>::handle h) const
+      -> test_result {
     struct test_buffer final : fmt::detail::buffer<char> {
       char data[10];
       test_buffer() : fmt::detail::buffer<char>(data, 0, 10) {}
@@ -463,13 +453,13 @@ TEST(arg_test, custom_arg) {
   auto test = test_struct();
   using visitor =
       mock_visitor<fmt::basic_format_arg<fmt::format_context>::handle>;
-  testing::StrictMock<visitor> v;
+  auto&& v = testing::StrictMock<visitor>();
   EXPECT_CALL(v, visit(_)).WillOnce(Invoke(check_custom()));
   fmt::visit_format_arg(v, fmt::detail::make_arg<fmt::format_context>(test));
 }
 
 TEST(arg_test, visit_invalid_arg) {
-  testing::StrictMock<mock_visitor<fmt::monostate>> visitor;
+  auto&& visitor = testing::StrictMock<mock_visitor<fmt::monostate>>();
   EXPECT_CALL(visitor, visit(_));
   auto arg = fmt::basic_format_arg<fmt::format_context>();
   fmt::visit_format_arg(visitor, arg);
@@ -477,186 +467,78 @@ TEST(arg_test, visit_invalid_arg) {
 
 #if FMT_USE_CONSTEXPR
 
-enum class arg_id_result { none, empty, index, name, error };
+enum class arg_id_result { none, empty, index, name };
 struct test_arg_id_handler {
   arg_id_result res = arg_id_result::none;
   int index = 0;
   string_view name;
 
-  constexpr void operator()() { res = arg_id_result::empty; }
+  constexpr void on_auto() { res = arg_id_result::empty; }
 
-  constexpr void operator()(int i) {
+  constexpr void on_index(int i) {
     res = arg_id_result::index;
     index = i;
   }
 
-  constexpr void operator()(string_view n) {
+  constexpr void on_name(string_view n) {
     res = arg_id_result::name;
     name = n;
   }
-
-  constexpr void on_error(const char*) { res = arg_id_result::error; }
 };
 
 template <size_t N>
 constexpr test_arg_id_handler parse_arg_id(const char (&s)[N]) {
-  test_arg_id_handler h;
+  auto h = test_arg_id_handler();
   fmt::detail::parse_arg_id(s, s + N, h);
   return h;
 }
 
-TEST(format_test, constexpr_parse_arg_id) {
+TEST(core_test, constexpr_parse_arg_id) {
   static_assert(parse_arg_id(":").res == arg_id_result::empty, "");
   static_assert(parse_arg_id("}").res == arg_id_result::empty, "");
   static_assert(parse_arg_id("42:").res == arg_id_result::index, "");
   static_assert(parse_arg_id("42:").index == 42, "");
   static_assert(parse_arg_id("foo:").res == arg_id_result::name, "");
   static_assert(parse_arg_id("foo:").name.size() == 3, "");
-  static_assert(parse_arg_id("!").res == arg_id_result::error, "");
 }
 
-struct test_format_specs_handler {
-  enum result { none, hash, zero, loc, error };
-  result res = none;
-
-  fmt::align_t alignment = fmt::align::none;
-  fmt::sign_t sign = fmt::sign::none;
-  char fill = 0;
-  int width = 0;
-  fmt::detail::arg_ref<char> width_ref;
-  int precision = 0;
-  fmt::detail::arg_ref<char> precision_ref;
-  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.
-  constexpr test_format_specs_handler() {}
-  constexpr test_format_specs_handler(const test_format_specs_handler& other) =
-      default;
-
-  constexpr void on_align(fmt::align_t a) { alignment = a; }
-  constexpr void on_fill(fmt::string_view f) { fill = f[0]; }
-  constexpr void on_sign(fmt::sign_t s) { sign = s; }
-  constexpr void on_hash() { res = hash; }
-  constexpr void on_zero() { res = zero; }
-  constexpr void on_localized() { res = loc; }
-
-  constexpr void on_width(int w) { width = w; }
-  constexpr void on_dynamic_width(fmt::detail::auto_id) {}
-  constexpr void on_dynamic_width(int index) { width_ref = index; }
-  constexpr void on_dynamic_width(string_view) {}
-
-  constexpr void on_precision(int p) { precision = p; }
-  constexpr void on_dynamic_precision(fmt::detail::auto_id) {}
-  constexpr void on_dynamic_precision(int index) { precision_ref = index; }
-  constexpr void on_dynamic_precision(string_view) {}
-
-  constexpr void end_precision() {}
-  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 - 1, h);
-  return h;
+template <size_t N> constexpr auto parse_test_specs(const char (&s)[N]) {
+  auto ctx = fmt::detail::compile_parse_context<char>(fmt::string_view(s, N),
+                                                      43, nullptr);
+  auto specs = fmt::detail::dynamic_format_specs<>();
+  fmt::detail::parse_format_specs(s, s + N - 1, specs, ctx,
+                                  fmt::detail::type::float_type);
+  return specs;
 }
 
 TEST(core_test, constexpr_parse_format_specs) {
-  using handler = test_format_specs_handler;
-  static_assert(parse_test_specs("<").alignment == fmt::align::left, "");
-  static_assert(parse_test_specs("*^").fill == '*', "");
+  static_assert(parse_test_specs("<").align == fmt::align::left, "");
+  static_assert(parse_test_specs("*^").fill[0] == '*', "");
   static_assert(parse_test_specs("+").sign == fmt::sign::plus, "");
   static_assert(parse_test_specs("-").sign == fmt::sign::minus, "");
   static_assert(parse_test_specs(" ").sign == fmt::sign::space, "");
-  static_assert(parse_test_specs("#").res == handler::hash, "");
-  static_assert(parse_test_specs("0").res == handler::zero, "");
-  static_assert(parse_test_specs("L").res == handler::loc, "");
+  static_assert(parse_test_specs("#").alt, "");
+  static_assert(parse_test_specs("0").align == fmt::align::numeric, "");
+  static_assert(parse_test_specs("L").localized, "");
   static_assert(parse_test_specs("42").width == 42, "");
   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 == fmt::presentation_type::dec, "");
-  static_assert(parse_test_specs("{<").res == handler::error, "");
-}
-
-struct test_parse_context {
-  using char_type = char;
-
-  constexpr int next_arg_id() { return 11; }
-  template <typename Id> FMT_CONSTEXPR void check_arg_id(Id) {}
-  FMT_CONSTEXPR void check_dynamic_spec(int) {}
-
-  constexpr const char* begin() { return nullptr; }
-  constexpr const char* end() { return nullptr; }
-
-  void on_error(const char*) {}
-};
-
-template <size_t N>
-constexpr fmt::detail::dynamic_format_specs<char> parse_dynamic_specs(
-    const char (&s)[N]) {
-  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 - 1, h);
-  return specs;
-}
-
-TEST(format_test, constexpr_dynamic_specs_handler) {
-  static_assert(parse_dynamic_specs("<").align == fmt::align::left, "");
-  static_assert(parse_dynamic_specs("*^").fill[0] == '*', "");
-  static_assert(parse_dynamic_specs("+").sign == fmt::sign::plus, "");
-  static_assert(parse_dynamic_specs("-").sign == fmt::sign::minus, "");
-  static_assert(parse_dynamic_specs(" ").sign == fmt::sign::space, "");
-  static_assert(parse_dynamic_specs("#").alt, "");
-  static_assert(parse_dynamic_specs("0").align == fmt::align::numeric, "");
-  static_assert(parse_dynamic_specs("42").width == 42, "");
-  static_assert(parse_dynamic_specs("{}").width_ref.val.index == 11, "");
-  static_assert(parse_dynamic_specs("{42}").width_ref.val.index == 42, "");
-  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 == 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 - 1, checker);
-  return checker;
-}
-
-TEST(format_test, constexpr_specs_checker) {
-  using handler = test_format_specs_handler;
-  static_assert(check_specs("<").alignment == fmt::align::left, "");
-  static_assert(check_specs("*^").fill == '*', "");
-  static_assert(check_specs("+").sign == fmt::sign::plus, "");
-  static_assert(check_specs("-").sign == fmt::sign::minus, "");
-  static_assert(check_specs(" ").sign == fmt::sign::space, "");
-  static_assert(check_specs("#").res == handler::hash, "");
-  static_assert(check_specs("0").res == handler::zero, "");
-  static_assert(check_specs("42").width == 42, "");
-  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 == fmt::presentation_type::dec, "");
-  static_assert(check_specs("{<").res == handler::error, "");
+  static_assert(
+      parse_test_specs("f").type == fmt::presentation_type::fixed_lower, "");
 }
 
 struct test_format_string_handler {
   constexpr void on_text(const char*, const char*) {}
 
-  constexpr int on_arg_id() { return 0; }
+  constexpr auto on_arg_id() -> int { return 0; }
 
-  template <typename T> constexpr int on_arg_id(T) { return 0; }
+  template <typename T> constexpr auto on_arg_id(T) -> int { return 0; }
 
   constexpr void on_replacement_field(int, const char*) {}
 
-  constexpr const char* on_format_specs(int, const char* begin, const char*) {
+  constexpr auto on_format_specs(int, const char* begin, const char*) -> const
+      char* {
     return begin;
   }
 
@@ -671,7 +553,7 @@ template <size_t N> constexpr bool parse_string(const char (&s)[N]) {
   return !h.error;
 }
 
-TEST(format_test, constexpr_parse_format_string) {
+TEST(core_test, constexpr_parse_format_string) {
   static_assert(parse_string("foo"), "");
   static_assert(!parse_string("}"), "");
   static_assert(parse_string("{}"), "");
@@ -693,7 +575,8 @@ template <> struct formatter<enabled_formatter> {
   auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
   }
-  auto format(enabled_formatter, format_context& ctx) -> decltype(ctx.out()) {
+  auto format(enabled_formatter, format_context& ctx) const
+      -> decltype(ctx.out()) {
     return ctx.out();
   }
 };
@@ -702,7 +585,7 @@ template <> struct formatter<enabled_ptr_formatter*> {
   auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
   }
-  auto format(enabled_ptr_formatter*, format_context& ctx)
+  auto format(enabled_ptr_formatter*, format_context& ctx) const
       -> decltype(ctx.out()) {
     return ctx.out();
   }
@@ -771,29 +654,17 @@ FMT_END_NAMESPACE
 
 enum class unformattable_scoped_enum {};
 
-namespace test {
-enum class formattable_scoped_enum {};
-auto format_as(formattable_scoped_enum) -> int { return 42; }
-
-struct convertible_to_enum {
-  operator formattable_scoped_enum() const { return {}; }
-};
-}  // namespace test
-
 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<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, "");
   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,
@@ -801,7 +672,8 @@ TEST(core_test, is_formattable) {
   static_assert(fmt::is_formattable<enabled_formatter>::value, "");
   static_assert(!fmt::is_formattable<enabled_ptr_formatter*>::value, "");
   static_assert(!fmt::is_formattable<disabled_formatter>::value, "");
-  static_assert(fmt::is_formattable<disabled_formatter_convertible>::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, "");
@@ -821,27 +693,28 @@ TEST(core_test, is_formattable) {
   static_assert(!fmt::is_formattable<int(s::*)>::value, "");
   static_assert(!fmt::is_formattable<int (s::*)()>::value, "");
   static_assert(!fmt::is_formattable<unformattable_scoped_enum>::value, "");
-  static_assert(fmt::is_formattable<test::formattable_scoped_enum>::value, "");
-  static_assert(!fmt::is_formattable<test::convertible_to_enum>::value, "");
+  static_assert(!fmt::is_formattable<unformattable_scoped_enum>::value, "");
 }
 
 TEST(core_test, format) { EXPECT_EQ(fmt::format("{}", 42), "42"); }
 
 TEST(core_test, format_to) {
-  std::string s;
+  auto s = std::string();
   fmt::format_to(std::back_inserter(s), "{}", 42);
   EXPECT_EQ(s, "42");
 }
 
-TEST(core_test, format_as) {
-  EXPECT_EQ(fmt::format("{}", test::formattable_scoped_enum()), "42");
+#ifdef __cpp_lib_byte
+TEST(core_test, format_byte) {
+  EXPECT_EQ(fmt::format("{}", std::byte(42)), "42");
 }
+#endif
 
 struct convertible_to_int {
   operator int() const { return 42; }
 };
 
-struct convertible_to_c_string {
+struct convertible_to_cstring {
   operator const char*() const { return "foo"; }
 };
 
@@ -850,16 +723,17 @@ template <> struct formatter<convertible_to_int> {
   auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
   }
-  auto format(convertible_to_int, format_context& ctx) -> decltype(ctx.out()) {
+  auto format(convertible_to_int, format_context& ctx) const
+      -> decltype(ctx.out()) {
     return std::copy_n("foo", 3, ctx.out());
   }
 };
 
-template <> struct formatter<convertible_to_c_string> {
+template <> struct formatter<convertible_to_cstring> {
   FMT_CONSTEXPR auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
   }
-  auto format(convertible_to_c_string, format_context& ctx)
+  auto format(convertible_to_cstring, format_context& ctx) const
       -> decltype(ctx.out()) {
     return std::copy_n("bar", 3, ctx.out());
   }
@@ -868,7 +742,7 @@ FMT_END_NAMESPACE
 
 TEST(core_test, formatter_overrides_implicit_conversion) {
   EXPECT_EQ(fmt::format("{}", convertible_to_int()), "foo");
-  EXPECT_EQ(fmt::format("{}", convertible_to_c_string()), "bar");
+  EXPECT_EQ(fmt::format("{}", convertible_to_cstring()), "bar");
 }
 
 // Test that check is not found by ADL.
@@ -877,27 +751,26 @@ TEST(core_test, adl_check) {
   EXPECT_EQ(fmt::format("{}", test_struct()), "test");
 }
 
-TEST(core_test, to_string_view_foreign_strings) {
-  using namespace test_ns;
-  EXPECT_EQ(to_string_view(test_string<char>("42")), "42");
-  fmt::detail::type type =
-      fmt::detail::mapped_type_constant<test_string<char>,
-                                        fmt::format_context>::value;
-  EXPECT_EQ(type, fmt::detail::type::string_type);
-}
-
-struct implicitly_convertible_to_string {
-  operator std::string() const { return "foo"; }
-};
-
 struct implicitly_convertible_to_string_view {
   operator fmt::string_view() const { return "foo"; }
 };
 
-TEST(core_test, format_implicitly_convertible_to_string_view) {
-  EXPECT_EQ("foo", fmt::format("{}", implicitly_convertible_to_string_view()));
+TEST(core_test, no_implicit_conversion_to_string_view) {
+  EXPECT_FALSE(
+      fmt::is_formattable<implicitly_convertible_to_string_view>::value);
 }
 
+#ifdef FMT_USE_STRING_VIEW
+struct implicitly_convertible_to_std_string_view {
+  operator std::string_view() const { return "foo"; }
+};
+
+TEST(core_test, no_implicit_conversion_to_std_string_view) {
+  EXPECT_FALSE(
+      fmt::is_formattable<implicitly_convertible_to_std_string_view>::value);
+}
+#endif
+
 // std::is_constructible is broken in MSVC until version 2015.
 #if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1900
 struct explicitly_convertible_to_string_view {
@@ -926,25 +799,6 @@ TEST(core_test, format_explicitly_convertible_to_std_string_view) {
 #  endif
 #endif
 
-struct convertible_to_long_long {
-  operator long long() const { return 1LL << 32; }
-};
-
-TEST(format_test, format_convertible_to_long_long) {
-  EXPECT_EQ("100000000", fmt::format("{:x}", convertible_to_long_long()));
-}
-
-struct disabled_rvalue_conversion {
-  operator const char*() const& { return "foo"; }
-  operator const char*() & { return "foo"; }
-  operator const char*() const&& = delete;
-  operator const char*() && = delete;
-};
-
-TEST(core_test, disabled_rvalue_conversion) {
-  EXPECT_EQ("foo", fmt::format("{}", disabled_rvalue_conversion()));
-}
-
 namespace adl_test {
 template <typename... T> void make_format_args(const T&...) = delete;
 

test/enforce-checks-test.cc

@@ -8,12 +8,14 @@
 #include <iterator>
 #include <vector>
 
+#define I 42  // simulate https://en.cppreference.com/w/c/numeric/complex/I
 #include "fmt/chrono.h"
 #include "fmt/color.h"
 #include "fmt/format.h"
 #include "fmt/ostream.h"
 #include "fmt/ranges.h"
 #include "fmt/xchar.h"
+#undef I
 
 // Exercise the API to verify that everything we expect to can compile.
 void test_format_api() {

test/find-package-test/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.18)
+cmake_minimum_required(VERSION 3.8...3.25)
 
 project(fmt-test)
 

test/format-impl-test.cc

@@ -242,11 +242,11 @@ TEST(fp_test, dragonbox_max_k) {
           floor_log10_pow2(std::numeric_limits<float>::min_exponent -
                            fmt::detail::num_significand_bits<float>() - 1));
   using double_info = fmt::detail::dragonbox::float_info<double>;
-  EXPECT_EQ(
-      fmt::detail::const_check(double_info::max_k),
-      double_info::kappa -
-          floor_log10_pow2(std::numeric_limits<double>::min_exponent -
-                           fmt::detail::num_significand_bits<double>() - 1));
+  EXPECT_EQ(fmt::detail::const_check(double_info::max_k),
+            double_info::kappa -
+                floor_log10_pow2(
+                    std::numeric_limits<double>::min_exponent -
+                    2 * fmt::detail::num_significand_bits<double>() - 1));
 }
 
 TEST(fp_test, get_round_direction) {
@@ -301,7 +301,7 @@ TEST(format_impl_test, format_error_code) {
   std::string msg = "error 42", sep = ": ";
   {
     auto buffer = fmt::memory_buffer();
-    format_to(fmt::appender(buffer), "garbage");
+    fmt::format_to(fmt::appender(buffer), "garbage");
     fmt::detail::format_error_code(buffer, 42, "test");
     EXPECT_EQ(to_string(buffer), "test: " + msg);
   }
@@ -353,6 +353,16 @@ TEST(format_impl_test, count_digits) {
   test_count_digits<uint64_t>();
 }
 
+TEST(format_impl_test, countl_zero) {
+  constexpr auto num_bits = fmt::detail::num_bits<uint32_t>();
+  uint32_t n = 1u;
+  for (int i = 1; i < num_bits - 1; i++) {
+    n <<= 1;
+    EXPECT_EQ(fmt::detail::countl_zero(n - 1), num_bits - i);
+    EXPECT_EQ(fmt::detail::countl_zero(n), num_bits - i - 1);
+  }
+}
+
 #if FMT_USE_FLOAT128
 TEST(format_impl_test, write_float128) {
   auto s = std::string();
@@ -372,6 +382,8 @@ struct double_double {
   auto operator-() const -> double_double { return double_double(-a, -b); }
 };
 
+auto format_as(double_double d) -> double { return d; }
+
 bool operator>=(const double_double& lhs, const double_double& rhs) {
   return lhs.a + lhs.b >= rhs.a + rhs.b;
 }
@@ -384,6 +396,8 @@ struct slow_float {
   auto operator-() const -> slow_float { return slow_float(-value); }
 };
 
+auto format_as(slow_float f) -> float { return f; }
+
 namespace std {
 template <> struct is_floating_point<double_double> : std::true_type {};
 template <> struct numeric_limits<double_double> {
@@ -545,3 +559,10 @@ TEST(format_impl_test, utf8_decode_bogus_byte_sequences) {
   EXPECT_NE(e, 0);    // "bogus [c0 0a] 0x%02x U+%04lx", e, (unsigned long)c
   EXPECT_EQ(len, 2);  // "bogus [c0 0a] recovery %d", len);
 }
+
+TEST(format_impl_test, unicode_to_utf8) {
+  auto s = std::string("ёжик");
+  fmt::detail::unicode_to_utf8<wchar_t> u(L"\x0451\x0436\x0438\x043A");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
+}

test/format-test.cc

@@ -646,7 +646,7 @@ TEST(format_test, fill) {
             fmt::format(string_view("{:\0>4}", 6), '*'));
   EXPECT_EQ("жж42", fmt::format("{0:ж>4}", 42));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{:\x80\x80\x80\x80\x80>}"), 0),
-                   format_error, "invalid type specifier");
+                   format_error, "invalid format specifier");
 }
 
 TEST(format_test, plus_sign) {
@@ -654,27 +654,25 @@ TEST(format_test, plus_sign) {
   EXPECT_EQ("-42", fmt::format("{0:+}", -42));
   EXPECT_EQ("+42", fmt::format("{0:+}", 42));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42u), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42l));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ul), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42ll));
 #if FMT_USE_INT128
   EXPECT_EQ("+42", fmt::format("{0:+}", __int128_t(42)));
 #endif
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ull), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("+42", fmt::format("{0:+}", 42.0));
   EXPECT_EQ("+42", fmt::format("{0:+}", 42.0l));
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+"), 'c'), format_error,
-                   "missing '}' in format string");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 'c'), format_error,
-                   "invalid format specifier for char");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), "abc"), format_error,
-                   "format specifier requires numeric argument");
+                   "invalid format specifier");
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0:+}"), reinterpret_cast<void*>(0x42)),
-      format_error, "format specifier requires numeric argument");
+      format_error, "invalid format specifier");
 }
 
 TEST(format_test, minus_sign) {
@@ -682,24 +680,22 @@ TEST(format_test, minus_sign) {
   EXPECT_EQ("-42", fmt::format("{0:-}", -42));
   EXPECT_EQ("42", fmt::format("{0:-}", 42));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42u), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("42", fmt::format("{0:-}", 42l));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ul), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("42", fmt::format("{0:-}", 42ll));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ull), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ("42", fmt::format("{0:-}", 42.0));
   EXPECT_EQ("42", fmt::format("{0:-}", 42.0l));
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-"), 'c'), format_error,
-                   "missing '}' in format string");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 'c'), format_error,
-                   "invalid format specifier for char");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), "abc"), format_error,
-                   "format specifier requires numeric argument");
+                   "invalid format specifier");
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0:-}"), reinterpret_cast<void*>(0x42)),
-      format_error, "format specifier requires numeric argument");
+      format_error, "invalid format specifier");
 }
 
 TEST(format_test, space_sign) {
@@ -707,24 +703,22 @@ TEST(format_test, space_sign) {
   EXPECT_EQ("-42", fmt::format("{0: }", -42));
   EXPECT_EQ(" 42", fmt::format("{0: }", 42));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42u), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42l));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ul), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42ll));
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ull), format_error,
-                   "format specifier requires signed argument");
+                   "invalid format specifier");
   EXPECT_EQ(" 42", fmt::format("{0: }", 42.0));
   EXPECT_EQ(" 42", fmt::format("{0: }", 42.0l));
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: "), 'c'), format_error,
-                   "missing '}' in format string");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 'c'), format_error,
-                   "invalid format specifier for char");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), "abc"), format_error,
-                   "format specifier requires numeric argument");
+                   "invalid format specifier");
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0: }"), reinterpret_cast<void*>(0x42)),
-      format_error, "format specifier requires numeric argument");
+      format_error, "invalid format specifier");
 }
 
 TEST(format_test, hash_flag) {
@@ -761,8 +755,8 @@ TEST(format_test, hash_flag) {
   EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42ull));
   EXPECT_EQ("042", fmt::format("{0:#o}", 042ull));
 
-  EXPECT_EQ("-42.0", fmt::format("{0:#}", -42.0));
-  EXPECT_EQ("-42.0", fmt::format("{0:#}", -42.0l));
+  EXPECT_EQ("-42.", fmt::format("{0:#}", -42.0));
+  EXPECT_EQ("-42.", fmt::format("{0:#}", -42.0l));
   EXPECT_EQ("4.e+01", fmt::format("{:#.0e}", 42.0));
   EXPECT_EQ("0.", fmt::format("{:#.0f}", 0.01));
   EXPECT_EQ("0.50", fmt::format("{:#.2g}", 0.5));
@@ -772,10 +766,10 @@ TEST(format_test, hash_flag) {
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), 'c'), format_error,
                    "invalid format specifier for char");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), "abc"), format_error,
-                   "format specifier requires numeric argument");
+                   "invalid format specifier");
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0:#}"), reinterpret_cast<void*>(0x42)),
-      format_error, "format specifier requires numeric argument");
+      format_error, "invalid format specifier");
 }
 
 TEST(format_test, zero_flag) {
@@ -799,6 +793,17 @@ TEST(format_test, zero_flag) {
       format_error, "format specifier requires numeric argument");
 }
 
+TEST(format_test, zero_flag_and_align) {
+  // If the 0 character and an align option both appear, the 0 character is
+  // ignored.
+  EXPECT_EQ("42   ", fmt::format("{0:<05}", 42));
+  EXPECT_EQ("-42  ", fmt::format("{0:<05}", -42));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^05}", 42));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^05}", -42));
+  EXPECT_EQ("   42", fmt::format("{0:>05}", 42));
+  EXPECT_EQ("  -42", fmt::format("{0:>05}", -42));
+}
+
 TEST(format_test, width) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:%u", UINT_MAX);
@@ -831,9 +836,9 @@ TEST(format_test, width) {
   EXPECT_EQ("str         ", fmt::format("{0:12}", "str"));
   EXPECT_EQ(fmt::format("{:*^6}", "🤡"), "**🤡**");
   EXPECT_EQ(fmt::format("{:*^8}", "你好"), "**你好**");
-  EXPECT_EQ(fmt::format("{:#6}", 42.0), "  42.0");
+  EXPECT_EQ(fmt::format("{:#6}", 42.0), "   42.");
   EXPECT_EQ(fmt::format("{:6c}", static_cast<int>('x')), "x     ");
-  EXPECT_EQ(fmt::format("{:>06.0f}", 0.00884311), "000000");
+  EXPECT_EQ(fmt::format("{:>06.0f}", 0.00884311), "     0");
 }
 
 TEST(format_test, runtime_width) {
@@ -902,54 +907,54 @@ TEST(format_test, precision) {
   char format_str[buffer_size];
   safe_sprintf(format_str, "{0:.%u", UINT_MAX);
   increment(format_str + 4);
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "number is too big");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "number is too big");
 
   safe_sprintf(format_str, "{0:.%u", INT_MAX + 1u);
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "number is too big");
   safe_sprintf(format_str, "{0:.%u}", INT_MAX + 1u);
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "number is too big");
 
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:."), 0), format_error,
-                   "missing precision specifier");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.}"), 0), format_error,
-                   "missing precision specifier");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:."), 0.0), format_error,
+                   "invalid precision");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.}"), 0.0), format_error,
+                   "invalid precision");
 
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2"), 0), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42u), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42u), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42l), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42l), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ul), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ul), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ll), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ll), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ull), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ull), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.0}"), 'x'), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345));
   EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345l));
   EXPECT_EQ("1.2e+56", fmt::format("{:.2}", 1.234e56));
@@ -1028,10 +1033,10 @@ TEST(format_test, precision) {
 
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0:.2}"), reinterpret_cast<void*>(0xcafe)),
-      format_error, "precision not allowed for this argument type");
+      format_error, "invalid format specifier");
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("{0:.2f}"), reinterpret_cast<void*>(0xcafe)),
-      format_error, "precision not allowed for this argument type");
+      format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{:.{}e}"), 42.0,
                                      fmt::detail::max_value<int>()),
                    format_error, "number is too big");
@@ -1047,97 +1052,86 @@ 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((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "invalid format string");
   size_t size = std::strlen(format_str);
   format_str[size] = '}';
   format_str[size + 1] = 0;
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "argument not found");
   format_str[size + 1] = '}';
   format_str[size + 2] = 0;
-  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0.0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{"), 0.0), format_error,
                    "invalid format string");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{}"), 0.0), format_error,
                    "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{?}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{?}}"), 0.0), format_error,
                    "invalid format string");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}"), 0, 0), format_error,
-                   "precision not allowed for this argument type");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0), format_error,
+                   "invalid format specifier");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0), format_error,
                    "argument not found");
 
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{0:}}"), 0), format_error,
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{0:}}"), 0.0), format_error,
                    "invalid format string");
 
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1), format_error,
-                   "negative precision");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1u)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, -1),
+                   format_error, "negative precision");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, (INT_MAX + 1u)),
                    format_error, "number is too big");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1l), format_error,
-                   "negative precision");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, -1l),
+                   format_error, "negative precision");
   if (fmt::detail::const_check(sizeof(long) > sizeof(int))) {
     long value = INT_MAX;
-    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (value + 1)),
+    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, (value + 1)),
                      format_error, "number is too big");
   }
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1ul)),
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, (INT_MAX + 1ul)),
                    format_error, "number is too big");
 
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, '0'), format_error,
-                   "precision is not integer");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, 0.0), format_error,
-                   "precision is not integer");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, '0'),
+                   format_error, "precision is not integer");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0.0, 0.0),
+                   format_error, "precision is not integer");
 
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42, 2), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42, 2), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42u, 2), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42u, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42l, 2), format_error,
-                   "precision not allowed for this argument type");
+                   "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42l, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ul, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ul, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ll, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ll, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ull, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ull, 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.{1}}"), 'x', 0),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   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((void)fmt::format(runtime("{0:.{1}}"),
                                      reinterpret_cast<void*>(0xcafe), 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"),
                                      reinterpret_cast<void*>(0xcafe), 2),
-                   format_error,
-                   "precision not allowed for this argument type");
+                   format_error, "invalid format specifier");
 
   EXPECT_EQ("st", fmt::format("{0:.{1}}", "str", 2));
 }
@@ -1167,7 +1161,7 @@ void check_unknown_types(const T& value, const char* types, const char*) {
     char c = static_cast<char>(i);
     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";
+    const char* message = "invalid format specifier";
     EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), value),
                      format_error, message)
         << format_str << " " << message;
@@ -1176,7 +1170,7 @@ void check_unknown_types(const T& value, const char* types, const char*) {
 
 TEST(format_test, format_int) {
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:v"), 42), format_error,
-                   "invalid type specifier");
+                   "invalid format specifier");
   check_unknown_types(42, "bBdoxXnLc", "integer");
   EXPECT_EQ("x", fmt::format("{:c}", static_cast<int>('x')));
 }
@@ -1205,6 +1199,7 @@ constexpr auto uint128_max = ~static_cast<__uint128_t>(0);
 TEST(format_test, format_dec) {
   EXPECT_EQ("0", fmt::format("{0}", 0));
   EXPECT_EQ("42", fmt::format("{0}", 42));
+  EXPECT_EQ("42>", fmt::format("{:}>", 42));
   EXPECT_EQ("42", fmt::format("{0:d}", 42));
   EXPECT_EQ("42", fmt::format("{0}", 42u));
   EXPECT_EQ("-42", fmt::format("{0}", -42));
@@ -1343,16 +1338,64 @@ TEST(format_test, format_double) {
   EXPECT_EQ(fmt::format("{:f}", 392.65), "392.650000");
   EXPECT_EQ(fmt::format("{:F}", 392.65), "392.650000");
   EXPECT_EQ(fmt::format("{:L}", 42.0), "42");
+  EXPECT_EQ(fmt::format("{:24a}", 4.2f), "           0x1.0cccccp+2");
   EXPECT_EQ(fmt::format("{:24a}", 4.2), "    0x1.0cccccccccccdp+2");
   EXPECT_EQ(fmt::format("{:<24a}", 4.2), "0x1.0cccccccccccdp+2    ");
   EXPECT_EQ(fmt::format("{0:e}", 392.65), "3.926500e+02");
   EXPECT_EQ(fmt::format("{0:E}", 392.65), "3.926500E+02");
   EXPECT_EQ(fmt::format("{0:+010.4g}", 392.65), "+0000392.6");
   char buffer[buffer_size];
-  safe_sprintf(buffer, "%a", -42.0);
-  EXPECT_EQ(fmt::format("{:a}", -42.0), buffer);
-  safe_sprintf(buffer, "%A", -42.0);
-  EXPECT_EQ(fmt::format("{:A}", -42.0), buffer);
+
+#if FMT_CPLUSPLUS >= 201703L
+  double xd = 0x1.ffffffffffp+2;
+  safe_sprintf(buffer, "%.*a", 10, xd);
+  EXPECT_EQ(fmt::format("{:.10a}", xd), buffer);
+  safe_sprintf(buffer, "%.*a", 9, xd);
+  EXPECT_EQ(fmt::format("{:.9a}", xd), buffer);
+
+  if (std::numeric_limits<long double>::digits == 64) {
+    auto ld = 0xf.ffffffffffp-3l;
+    safe_sprintf(buffer, "%La", ld);
+    EXPECT_EQ(fmt::format("{:a}", ld), buffer);
+    safe_sprintf(buffer, "%.*La", 10, ld);
+    EXPECT_EQ(fmt::format("{:.10a}", ld), buffer);
+    safe_sprintf(buffer, "%.*La", 9, ld);
+    EXPECT_EQ(fmt::format("{:.9a}", ld), buffer);
+  }
+#endif
+
+  if (fmt::detail::const_check(std::numeric_limits<double>::is_iec559)) {
+    double d = (std::numeric_limits<double>::min)();
+    EXPECT_EQ(fmt::format("{:a}", d), "0x1p-1022");
+    EXPECT_EQ(fmt::format("{:#a}", d), "0x1.p-1022");
+
+    d = (std::numeric_limits<double>::max)();
+    safe_sprintf(buffer, "%a", d);
+    EXPECT_EQ(fmt::format("{:a}", d), buffer);
+
+    d = std::numeric_limits<double>::denorm_min();
+    EXPECT_EQ(fmt::format("{:a}", d), "0x0.0000000000001p-1022");
+  }
+
+  if (std::numeric_limits<long double>::digits == 64) {
+    auto ld = (std::numeric_limits<long double>::min)();
+    safe_sprintf(buffer, "%La", ld);
+    EXPECT_EQ(fmt::format("{:a}", ld), buffer);
+
+    ld = (std::numeric_limits<long double>::max)();
+    safe_sprintf(buffer, "%La", ld);
+    EXPECT_EQ(fmt::format("{:a}", ld), buffer);
+
+    ld = std::numeric_limits<long double>::denorm_min();
+    EXPECT_EQ(fmt::format("{:a}", ld), "0x0.000000000000001p-16382");
+  }
+
+  safe_sprintf(buffer, "%.*a", 10, 4.2);
+  EXPECT_EQ(fmt::format("{:.10a}", 4.2), buffer);
+
+  EXPECT_EQ(fmt::format("{:a}", -42.0), "-0x1.5p+5");
+  EXPECT_EQ(fmt::format("{:A}", -42.0), "-0X1.5P+5");
+
   EXPECT_EQ(fmt::format("{:f}", 9223372036854775807.0),
             "9223372036854775808.000000");
 }
@@ -1446,8 +1489,15 @@ TEST(format_test, format_long_double) {
   safe_sprintf(buffer, "%Le", 392.65l);
   EXPECT_EQ(buffer, fmt::format("{0:e}", 392.65l));
   EXPECT_EQ("+0000392.6", fmt::format("{0:+010.4g}", 392.64l));
-  safe_sprintf(buffer, "%La", 3.31l);
-  EXPECT_EQ(buffer, fmt::format("{:a}", 3.31l));
+
+  auto ld = 3.31l;
+  if (fmt::detail::is_double_double<decltype(ld)>::value) {
+    safe_sprintf(buffer, "%a", static_cast<double>(ld));
+    EXPECT_EQ(buffer, fmt::format("{:a}", ld));
+  } else {
+    safe_sprintf(buffer, "%La", ld);
+    EXPECT_EQ(buffer, fmt::format("{:a}", ld));
+  }
 }
 
 TEST(format_test, format_char) {
@@ -1466,6 +1516,7 @@ TEST(format_test, format_char) {
 
   EXPECT_EQ("\n", fmt::format("{}", '\n'));
   EXPECT_EQ("'\\n'", fmt::format("{:?}", '\n'));
+  EXPECT_EQ("ff", fmt::format("{:x}", '\xff'));
 }
 
 TEST(format_test, format_volatile_char) {
@@ -1507,6 +1558,12 @@ TEST(format_test, format_pointer) {
   std::unique_ptr<int> up(new int(1));
   EXPECT_EQ(fmt::format("{}", fmt::ptr(up.get())),
             fmt::format("{}", fmt::ptr(up)));
+  struct custom_deleter {
+    void operator()(int* p) const { delete p; }
+  };
+  std::unique_ptr<int, custom_deleter> upcd(new int(1));
+  EXPECT_EQ(fmt::format("{}", fmt::ptr(upcd.get())),
+            fmt::format("{}", fmt::ptr(upcd)));
   std::shared_ptr<int> sp(new int(1));
   EXPECT_EQ(fmt::format("{}", fmt::ptr(sp.get())),
             fmt::format("{}", fmt::ptr(sp)));
@@ -1581,7 +1638,7 @@ struct fmt::formatter<explicitly_convertible_to_std_string_view>
     : formatter<std::string_view> {
   auto format(explicitly_convertible_to_std_string_view v, format_context& ctx)
       -> decltype(ctx.out()) {
-    return format_to(ctx.out(), "'{}'", std::string_view(v));
+    return fmt::format_to(ctx.out(), "'{}'", std::string_view(v));
   }
 };
 
@@ -1591,27 +1648,6 @@ TEST(format_test, format_explicitly_convertible_to_std_string_view) {
 }
 #endif
 
-struct converible_to_anything {
-  template <typename T> operator T() const { return T(); }
-};
-
-FMT_BEGIN_NAMESPACE
-template <> struct formatter<converible_to_anything> {
-  FMT_CONSTEXPR auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  auto format(converible_to_anything, format_context& ctx)
-      -> decltype(ctx.out()) {
-    return format_to(ctx.out(), "foo");
-  }
-};
-FMT_END_NAMESPACE
-
-TEST(format_test, format_convertible_to_anything) {
-  EXPECT_EQ("foo", fmt::format("{}", converible_to_anything()));
-}
-
 class Answer {};
 
 FMT_BEGIN_NAMESPACE
@@ -1624,7 +1660,8 @@ template <> struct formatter<date> {
   }
 
   auto format(const date& d, format_context& ctx) -> decltype(ctx.out()) {
-    format_to(ctx.out(), "{}-{}-{}", d.year(), d.month(), d.day());
+    // Namespace-qualify to avoid ambiguity with std::format_to.
+    fmt::format_to(ctx.out(), "{}-{}-{}", d.year(), d.month(), d.day());
     return ctx.out();
   }
 };
@@ -1665,7 +1702,7 @@ TEST(format_test, format_examples) {
   EXPECT_EQ("42", fmt::format("{}", 42));
 
   memory_buffer out;
-  format_to(std::back_inserter(out), "The answer is {}.", 42);
+  fmt::format_to(std::back_inserter(out), "The answer is {}.", 42);
   EXPECT_EQ("The answer is 42.", to_string(out));
 
   const char* filename = "nonexistent";
@@ -1717,7 +1754,7 @@ TEST(format_test, format_examples) {
   EXPECT_EQ("The answer is 42", fmt::format("The answer is {}", 42));
   EXPECT_THROW_MSG(
       (void)fmt::format(runtime("The answer is {:d}"), "forty-two"),
-      format_error, "invalid type specifier");
+      format_error, "invalid format specifier");
 
   EXPECT_WRITE(
       stdout, fmt::print("{}", std::numeric_limits<double>::infinity()), "inf");
@@ -1727,6 +1764,9 @@ TEST(format_test, print) {
   EXPECT_WRITE(stdout, fmt::print("Don't {}!", "panic"), "Don't panic!");
   EXPECT_WRITE(stderr, fmt::print(stderr, "Don't {}!", "panic"),
                "Don't panic!");
+  EXPECT_WRITE(stdout, fmt::println("Don't {}!", "panic"), "Don't panic!\n");
+  EXPECT_WRITE(stderr, fmt::println(stderr, "Don't {}!", "panic"),
+               "Don't panic!\n");
 }
 
 TEST(format_test, variadic) {
@@ -1789,12 +1829,6 @@ TEST(format_test, join) {
 }
 
 #ifdef __cpp_lib_byte
-TEST(format_test, format_byte) {
-  using arg_mapper = fmt::detail::arg_mapper<fmt::format_context>;
-  EXPECT_EQ(arg_mapper().map(std::byte(42)), 42);
-  EXPECT_EQ(fmt::format("{}", std::byte(42)), "42");
-}
-
 TEST(format_test, join_bytes) {
   auto v = std::vector<std::byte>{std::byte(1), std::byte(2), std::byte(3)};
   EXPECT_EQ(fmt::format("{}", fmt::join(v, ", ")), "1, 2, 3");
@@ -1803,7 +1837,7 @@ TEST(format_test, join_bytes) {
 
 std::string vformat_message(int id, const char* format, fmt::format_args args) {
   auto buffer = fmt::memory_buffer();
-  format_to(fmt::appender(buffer), "[{}] ", id);
+  fmt::format_to(fmt::appender(buffer), "[{}] ", id);
   vformat_to(fmt::appender(buffer), format, args);
   return to_string(buffer);
 }
@@ -1832,9 +1866,6 @@ TEST(format_test, unpacked_args) {
                         6, 7, 8, 9, 'a', 'b', 'c', 'd', 'e', 'f', 'g'));
 }
 
-struct string_like {};
-fmt::string_view to_string_view(string_like) { return "foo"; }
-
 constexpr char with_null[3] = {'{', '}', '\0'};
 constexpr char no_null[2] = {'{', '}'};
 static constexpr const char static_with_null[3] = {'{', '}', '\0'};
@@ -1843,7 +1874,6 @@ static constexpr const char static_no_null[2] = {'{', '}'};
 TEST(format_test, compile_time_string) {
   EXPECT_EQ("foo", fmt::format(FMT_STRING("foo")));
   EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), 42));
-  EXPECT_EQ("foo", fmt::format(FMT_STRING("{}"), string_like()));
 
 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
   using namespace fmt::literals;
@@ -1852,6 +1882,7 @@ TEST(format_test, compile_time_string) {
   EXPECT_EQ("", fmt::format(FMT_STRING("")));
   EXPECT_EQ("", fmt::format(FMT_STRING(""), "arg"_a = 42));
   EXPECT_EQ("42", fmt::format(FMT_STRING("{answer}"), "answer"_a = Answer()));
+  EXPECT_EQ("1 2", fmt::format(FMT_STRING("{} {two}"), 1, "two"_a = 2));
 #endif
 
   (void)static_with_null;
@@ -1917,46 +1948,6 @@ TEST(format_test, non_null_terminated_format_string) {
   EXPECT_EQ("42", fmt::format(string_view("{}foo", 2), 42));
 }
 
-struct variant {
-  enum { int_type, string_type } type;
-  explicit variant(int) : type(int_type) {}
-  explicit variant(const char*) : type(string_type) {}
-};
-
-FMT_BEGIN_NAMESPACE
-template <> struct formatter<variant> : dynamic_formatter<> {
-  auto format(variant value, format_context& ctx) -> decltype(ctx.out()) {
-    if (value.type == variant::int_type)
-      return dynamic_formatter<>::format(42, ctx);
-    return dynamic_formatter<>::format("foo", ctx);
-  }
-};
-FMT_END_NAMESPACE
-
-TEST(format_test, dynamic_formatter) {
-  auto num = variant(42);
-  auto str = variant("foo");
-  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((void)fmt::format(runtime("{0:{}}"), num), format_error,
-                   "cannot switch from manual to automatic argument indexing");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:{0}}"), num), format_error,
-                   "cannot switch from automatic to manual argument indexing");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:+}"), str), format_error,
-                   "format specifier requires numeric argument");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:-}"), str), format_error,
-                   "format specifier requires numeric argument");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{: }"), str), format_error,
-                   "format specifier requires numeric argument");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:#}"), str), format_error,
-                   "format specifier requires numeric argument");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:0}"), str), format_error,
-                   "format specifier requires numeric argument");
-  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.2}"), num), format_error,
-                   "precision not allowed for this argument type");
-}
-
 namespace adl_test {
 namespace fmt {
 namespace detail {
@@ -1969,30 +1960,26 @@ template <typename, typename OutputIt> void write(OutputIt, foo) = delete;
 FMT_BEGIN_NAMESPACE
 template <>
 struct formatter<adl_test::fmt::detail::foo> : formatter<std::string> {
-  template <typename FormatContext>
-  auto format(adl_test::fmt::detail::foo, FormatContext& ctx)
+  auto format(adl_test::fmt::detail::foo, format_context& ctx)
       -> decltype(ctx.out()) {
     return formatter<std::string>::format("foo", ctx);
   }
 };
 FMT_END_NAMESPACE
 
-struct convertible_to_int {
-  operator int() const { return value; }
-
-  int value = 42;
-};
-
 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");
   EXPECT_EQ(fmt::to_string(foo), "0");
 
 #if FMT_USE_FLOAT128
   EXPECT_EQ(fmt::to_string(__float128(0.5)), "0.5");
 #endif
+
+#if defined(FMT_USE_STRING_VIEW) && FMT_CPLUSPLUS >= 201703L
+  EXPECT_EQ(fmt::to_string(std::string_view()), "");
+#endif
 }
 
 TEST(format_test, output_iterators) {
@@ -2006,6 +1993,7 @@ TEST(format_test, output_iterators) {
 
 TEST(format_test, formatted_size) {
   EXPECT_EQ(2u, fmt::formatted_size("{}", 42));
+  EXPECT_EQ(2u, fmt::formatted_size(std::locale(), "{}", 42));
 }
 
 TEST(format_test, format_to_no_args) {
@@ -2108,116 +2096,6 @@ TEST(format_test, format_to_n_output_iterator) {
   EXPECT_STREQ(buf, "42");
 }
 
-#if FMT_USE_CONSTEXPR
-struct test_error_handler {
-  const char*& error;
-
-  FMT_CONSTEXPR test_error_handler(const char*& err) : error(err) {}
-
-  FMT_CONSTEXPR test_error_handler(const test_error_handler& other)
-      : error(other.error) {}
-
-  FMT_CONSTEXPR void on_error(const char* message) {
-    if (!error) error = message;
-  }
-};
-
-FMT_CONSTEXPR size_t len(const char* s) {
-  size_t len = 0;
-  while (*s++) ++len;
-  return len;
-}
-
-FMT_CONSTEXPR bool equal(const char* s1, const char* s2) {
-  if (!s1 || !s2) return s1 == s2;
-  while (*s1 && *s1 == *s2) {
-    ++s1;
-    ++s2;
-  }
-  return *s1 == *s2;
-}
-
-template <typename... Args>
-FMT_CONSTEXPR bool test_error(const char* fmt, const char* expected_error) {
-  const char* actual_error = nullptr;
-  auto s = string_view(fmt, len(fmt));
-  auto checker =
-      fmt::detail::format_string_checker<char, test_error_handler, Args...>(
-          s, test_error_handler(actual_error));
-  fmt::detail::parse_format_string<true>(s, checker);
-  return equal(actual_error, expected_error);
-}
-
-#  define EXPECT_ERROR_NOARGS(fmt, error) \
-    static_assert(test_error(fmt, error), "")
-#  define EXPECT_ERROR(fmt, error, ...) \
-    static_assert(test_error<__VA_ARGS__>(fmt, error), "")
-
-TEST(format_test, format_string_errors) {
-  EXPECT_ERROR_NOARGS("foo", nullptr);
-  EXPECT_ERROR_NOARGS("}", "unmatched '}' in format string");
-  EXPECT_ERROR("{0:s", "unknown format specifier", date);
-#  if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1916
-  // This causes an detail compiler error in MSVC2017.
-  EXPECT_ERROR("{:{<}", "invalid fill character '{'", int);
-  EXPECT_ERROR("{:10000000000}", "number is too big", int);
-  EXPECT_ERROR("{:.10000000000}", "number is too big", int);
-  EXPECT_ERROR_NOARGS("{:x}", "argument not found");
-  EXPECT_ERROR("{:+}", "format specifier requires numeric argument",
-               const char*);
-  EXPECT_ERROR("{:-}", "format specifier requires numeric argument",
-               const char*);
-  EXPECT_ERROR("{:#}", "format specifier requires numeric argument",
-               const char*);
-  EXPECT_ERROR("{: }", "format specifier requires numeric argument",
-               const char*);
-  EXPECT_ERROR("{:0}", "format specifier requires numeric argument",
-               const char*);
-  EXPECT_ERROR("{:+}", "format specifier requires signed argument", unsigned);
-  EXPECT_ERROR("{:-}", "format specifier requires signed argument", unsigned);
-  EXPECT_ERROR("{: }", "format specifier requires signed argument", unsigned);
-  EXPECT_ERROR("{:{}}", "argument not found", int);
-  EXPECT_ERROR("{:.{}}", "argument not found", double);
-  EXPECT_ERROR("{:{}}", "width/precision is not integer", int, double);
-  EXPECT_ERROR("{:.2}", "precision not allowed for this argument type", int);
-  EXPECT_ERROR("{:s}", "invalid type specifier", int);
-  EXPECT_ERROR("{:s}", "invalid type specifier", char);
-  EXPECT_ERROR("{:+}", "invalid format specifier for char", char);
-  EXPECT_ERROR("{:s}", "invalid type specifier", double);
-  EXPECT_ERROR("{:d}", "invalid type specifier", const char*);
-  EXPECT_ERROR("{:d}", "invalid type specifier", std::string);
-  EXPECT_ERROR("{:s}", "invalid type specifier", void*);
-#  else
-  fmt::print("warning: constexpr is broken in this version of MSVC\n");
-#  endif
-#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
-  using namespace fmt::literals;
-  EXPECT_ERROR("{foo}", "named argument is not found", decltype("bar"_a = 42));
-  EXPECT_ERROR("{foo}", "named argument is not found",
-               decltype(fmt::arg("foo", 42)));
-#  else
-  EXPECT_ERROR("{foo}",
-               "compile-time checks for named arguments require C++20 support",
-               int);
-#  endif
-  EXPECT_ERROR_NOARGS("{10000000000}", "argument not found");
-  EXPECT_ERROR_NOARGS("{0x}", "invalid format string");
-  EXPECT_ERROR_NOARGS("{-}", "invalid format string");
-  EXPECT_ERROR("{:{0x}}", "invalid format string", int);
-  EXPECT_ERROR("{:{-}}", "invalid format string", int);
-  EXPECT_ERROR("{:.{0x}}", "invalid format string", int);
-  EXPECT_ERROR("{:.{-}}", "invalid format string", int);
-  EXPECT_ERROR("{:.x}", "missing precision specifier", int);
-  EXPECT_ERROR_NOARGS("{}", "argument not found");
-  EXPECT_ERROR("{1}", "argument not found", int);
-  EXPECT_ERROR("{1}{}",
-               "cannot switch from manual to automatic argument indexing", int,
-               int);
-  EXPECT_ERROR("{}{1}",
-               "cannot switch from automatic to manual argument indexing", int,
-               int);
-}
-
 TEST(format_test, vformat_to) {
   using context = fmt::format_context;
   fmt::basic_format_arg<context> arg = fmt::detail::make_arg<context>(42);
@@ -2230,8 +2108,6 @@ TEST(format_test, vformat_to) {
   EXPECT_EQ("42", s);
 }
 
-#endif  // FMT_USE_CONSTEXPR
-
 TEST(format_test, char_traits_is_not_ambiguous) {
   // Test that we don't inject detail names into the std namespace.
   using namespace std;
@@ -2267,6 +2143,27 @@ TEST(format_test, back_insert_slicing) {
   EXPECT_EQ(fmt::format("{}", check_back_appender{}), "y");
 }
 
+namespace test {
+enum class scoped_enum_as_int {};
+auto format_as(scoped_enum_as_int) -> int { return 42; }
+
+enum class scoped_enum_as_string_view {};
+auto format_as(scoped_enum_as_string_view) -> fmt::string_view { return "foo"; }
+
+enum class scoped_enum_as_string {};
+auto format_as(scoped_enum_as_string) -> std::string { return "foo"; }
+
+struct struct_as_int {};
+auto format_as(struct_as_int) -> int { return 42; }
+}  // namespace test
+
+TEST(format_test, format_as) {
+  EXPECT_EQ(fmt::format("{}", test::scoped_enum_as_int()), "42");
+  EXPECT_EQ(fmt::format("{}", test::scoped_enum_as_string_view()), "foo");
+  EXPECT_EQ(fmt::format("{}", test::scoped_enum_as_string()), "foo");
+  EXPECT_EQ(fmt::format("{}", test::struct_as_int()), "42");
+}
+
 template <typename Char, typename T> bool check_enabled_formatter() {
   static_assert(std::is_default_constructible<fmt::formatter<T, Char>>::value,
                 "");
@@ -2309,3 +2206,62 @@ TEST(format_int_test, format_int) {
   os << max_value<int64_t>();
   EXPECT_EQ(os.str(), fmt::format_int(max_value<int64_t>()).str());
 }
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+
+#  include <locale>
+
+class format_facet : public fmt::format_facet<std::locale> {
+ protected:
+  struct int_formatter {
+    fmt::appender out;
+
+    template <typename T, FMT_ENABLE_IF(fmt::detail::is_integer<T>::value)>
+    auto operator()(T value) -> bool {
+      fmt::format_to(out, "[{}]", value);
+      return true;
+    }
+
+    template <typename T, FMT_ENABLE_IF(!fmt::detail::is_integer<T>::value)>
+    auto operator()(T) -> bool {
+      return false;
+    }
+  };
+
+  auto do_put(fmt::appender out, fmt::loc_value val,
+              const fmt::format_specs<>&) const -> bool override;
+};
+
+auto format_facet::do_put(fmt::appender out, fmt::loc_value val,
+                          const fmt::format_specs<>&) const -> bool {
+  return val.visit(int_formatter{out});
+}
+
+TEST(format_test, format_facet) {
+  auto loc = std::locale(std::locale(), new format_facet());
+  EXPECT_EQ(fmt::format(loc, "{:L}", 42), "[42]");
+  EXPECT_EQ(fmt::format(loc, "{:L}", -42), "[-42]");
+}
+
+TEST(format_test, format_facet_separator) {
+  // U+2019 RIGHT SINGLE QUOTATION MARK is a digit separator in the de_CH
+  // locale.
+  auto loc =
+      std::locale({}, new fmt::format_facet<std::locale>("\xe2\x80\x99"));
+  EXPECT_EQ(fmt::format(loc, "{:L}", 1000),
+            "1\xe2\x80\x99"
+            "000");
+}
+
+TEST(format_test, format_facet_grouping) {
+  auto loc =
+      std::locale({}, new fmt::format_facet<std::locale>(",", {1, 2, 3}));
+  EXPECT_EQ(fmt::format(loc, "{:L}", 1234567890), "1,234,567,89,0");
+}
+
+TEST(format_test, format_named_arg_with_locale) {
+  EXPECT_EQ(fmt::format(std::locale(), "{answer}", fmt::arg("answer", 42)),
+            "42");
+}
+
+#endif  // FMT_STATIC_THOUSANDS_SEPARATOR

test/fuzzing/CMakeLists.txt

@@ -22,7 +22,7 @@ function(add_fuzzer source)
   if (FMT_FUZZ_LDFLAGS)
     target_link_libraries(${name} PRIVATE ${FMT_FUZZ_LDFLAGS})
   endif ()
-  target_compile_features(${name} PRIVATE cxx_generic_lambdas)
+  target_compile_features(${name} PRIVATE cxx_std_14)
 endfunction()
 
 foreach (source chrono-duration.cc chrono-timepoint.cc float.cc named-arg.cc one-arg.cc two-args.cc)

test/gtest-extra-test.cc

@@ -201,6 +201,7 @@ TEST(gtest_extra_test, expect_write_streaming) {
 // EXPECT_THROW_MSG macro.
 TEST(gtest_extra_test, expect_throw_no_unreachable_code_warning) {
   int n = 0;
+  (void)n;
   using std::runtime_error;
   EXPECT_THROW_MSG(throw runtime_error(""), runtime_error, "");
   EXPECT_NONFATAL_FAILURE(EXPECT_THROW_MSG(n++, runtime_error, ""), "");
@@ -213,6 +214,7 @@ TEST(gtest_extra_test, expect_throw_no_unreachable_code_warning) {
 // EXPECT_SYSTEM_ERROR macro.
 TEST(gtest_extra_test, expect_system_error_no_unreachable_code_warning) {
   int n = 0;
+  (void)n;
   EXPECT_SYSTEM_ERROR(throw fmt::system_error(EDOM, "test"), EDOM, "test");
   EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(n++, EDOM, ""), "");
   EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(throw 1, EDOM, ""), "");

test/gtest-extra.h

@@ -12,12 +12,7 @@
 
 #include <string>
 
-#ifdef FMT_MODULE_TEST
-import fmt;
-#else
-#  include "fmt/os.h"
-#endif  // FMG_MODULE_TEST
-
+#include "fmt/os.h"
 #include "gmock/gmock.h"
 
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \

test/gtest/CMakeLists.txt

@@ -9,6 +9,7 @@ add_library(gtest STATIC
   gmock-gtest-all.cc gmock/gmock.h gtest/gtest.h gtest/gtest-spi.h)
 target_compile_definitions(gtest PUBLIC GTEST_HAS_STD_WSTRING=1)
 target_include_directories(gtest SYSTEM PUBLIC .)
+target_compile_features(gtest PUBLIC cxx_std_11)
 
 find_package(Threads)
 if (Threads_FOUND)
@@ -17,13 +18,6 @@ else ()
   target_compile_definitions(gtest PUBLIC GTEST_HAS_PTHREAD=0)
 endif ()
 
-# Workaround GTest bug https://github.com/google/googletest/issues/705.
-fmt_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/gtest/gmock-gtest-all.cc

@@ -13778,7 +13778,7 @@ UntypedActionResultHolderBase* UntypedFunctionMockerBase::UntypedInvokeWith(
 
   UntypedActionResultHolderBase* result = nullptr;
 
-  auto perform_action = [&] {
+  auto perform_action = [&, this] {
     return untyped_action == nullptr
                ? this->UntypedPerformDefaultAction(untyped_args, ss.str())
                : this->UntypedPerformAction(untyped_action, untyped_args);

test/mock-allocator.h

@@ -20,8 +20,8 @@ template <typename T> class mock_allocator {
   mock_allocator() {}
   mock_allocator(const mock_allocator&) {}
   using value_type = T;
-  MOCK_METHOD1_T(allocate, T*(size_t n));
-  MOCK_METHOD2_T(deallocate, void(T* p, size_t n));
+  MOCK_METHOD(T*, allocate, (size_t));
+  MOCK_METHOD(void, deallocate, (T*, size_t));
 };
 
 template <typename Allocator> class allocator_ref {

test/module-test.cc

@@ -15,8 +15,6 @@
 #  define FMT_HIDE_MODULE_BUGS
 #endif
 
-#define FMT_MODULE_TEST
-
 #include <bit>
 #include <chrono>
 #include <exception>
@@ -41,7 +39,6 @@
 #else
 #  define FMT_POSIX(call) call
 #endif
-#define FMT_OS_H_  // don't pull in os.h directly or indirectly
 
 import fmt;
 
@@ -53,13 +50,8 @@ static bool macro_leaked =
     false;
 #endif
 
-// 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"
+#define FMT_OS_H_  // don't pull in os.h, neither directly nor indirectly
+#include "gtest-extra.h"
 
 // an implicitly exported namespace must be visible [module.interface]/2.2
 TEST(module_test, namespace) {
@@ -75,9 +67,8 @@ bool oops_detail_namespace_is_visible;
 namespace fmt {
 bool namespace_detail_invisible() {
 #if defined(FMT_HIDE_MODULE_BUGS) && defined(_MSC_FULL_VER) && \
-    ((_MSC_VER == 1929 && _MSC_FULL_VER <= 192930136) ||       \
-     (_MSC_VER == 1930 && _MSC_FULL_VER <= 193030704))
-  // bug in msvc up to 16.11.5 / 17.0-pre5:
+    _MSC_FULL_VER <= 193700000
+  // bug in msvc up to at least 17.7:
 
   // the namespace is visible even when it is neither
   // implicitly nor explicitly exported
@@ -111,7 +102,7 @@ TEST(module_test, macros) {
 // but rather visibility of all client-facing overloads, reachability of
 // non-exported entities, name lookup and overload resolution within
 // template instantitions.
-// Excercise all exported entities of the API at least once.
+// Exercise all exported entities of the API at least once.
 // Instantiate as many code paths as possible.
 
 TEST(module_test, to_string) {
@@ -140,7 +131,7 @@ TEST(module_test, format_to) {
   EXPECT_EQ("42", std::string_view(buffer));
 
   fmt::memory_buffer mb;
-  fmt::format_to(mb, "{}", 42);
+  fmt::format_to(std::back_inserter(mb), "{}", 42);
   EXPECT_EQ("42", std::string_view(buffer));
 
   std::wstring w;
@@ -152,7 +143,7 @@ TEST(module_test, format_to) {
   EXPECT_EQ(L"42", std::wstring_view(wbuffer));
 
   fmt::wmemory_buffer wb;
-  fmt::format_to(wb, L"{}", 42);
+  fmt::format_to(std::back_inserter(wb), L"{}", 42);
   EXPECT_EQ(L"42", std::wstring_view(wbuffer));
 }
 
@@ -211,8 +202,8 @@ TEST(module_test, dynamic_format_args) {
 
 TEST(module_test, vformat) {
   EXPECT_EQ("42", fmt::vformat("{}", fmt::make_format_args(42)));
-  EXPECT_EQ(L"42", fmt::vformat(fmt::to_string_view(L"{}"),
-                                fmt::make_wformat_args(42)));
+  EXPECT_EQ(L"42",
+            fmt::vformat(fmt::wstring_view(L"{}"), fmt::make_wformat_args(42)));
 }
 
 TEST(module_test, vformat_to) {
@@ -245,9 +236,9 @@ TEST(module_test, vformat_to_n) {
   auto wstore = fmt::make_wformat_args(12345);
   std::wstring w;
   auto wresult = fmt::vformat_to_n(std::back_inserter(w), 1,
-                                   fmt::to_string_view(L"{}"), wstore);
+                                   fmt::wstring_view(L"{}"), wstore);
   wchar_t wbuffer[4] = {0};
-  fmt::vformat_to_n(wbuffer, 3, fmt::to_string_view(L"{:}"), wstore);
+  fmt::vformat_to_n(wbuffer, 3, fmt::wstring_view(L"{:}"), wstore);
 }
 
 std::string as_string(std::wstring_view text) {
@@ -258,22 +249,18 @@ std::string as_string(std::wstring_view text) {
 TEST(module_test, print) {
   EXPECT_WRITE(stdout, fmt::print("{}µ", 42), "42µ");
   EXPECT_WRITE(stderr, fmt::print(stderr, "{}µ", 4.2), "4.2µ");
-  if (false) {
-    EXPECT_WRITE(stdout, fmt::print(L"{}µ", 42), as_string(L"42µ"));
-    EXPECT_WRITE(stderr, fmt::print(stderr, L"{}µ", 4.2), as_string(L"4.2µ"));
-  }
+  EXPECT_WRITE(stdout, fmt::print(L"{}µ", 42), as_string(L"42µ"));
+  EXPECT_WRITE(stderr, fmt::print(stderr, L"{}µ", 4.2), as_string(L"4.2µ"));
 }
 
 TEST(module_test, vprint) {
   EXPECT_WRITE(stdout, fmt::vprint("{:}µ", fmt::make_format_args(42)), "42µ");
   EXPECT_WRITE(stderr, fmt::vprint(stderr, "{}", fmt::make_format_args(4.2)),
                "4.2");
-  if (false) {
-    EXPECT_WRITE(stdout, fmt::vprint(L"{:}µ", fmt::make_wformat_args(42)),
-                 as_string(L"42µ"));
-    EXPECT_WRITE(stderr, fmt::vprint(stderr, L"{}", fmt::make_wformat_args(42)),
-                 as_string(L"42"));
-  }
+  EXPECT_WRITE(stdout, fmt::vprint(L"{:}µ", fmt::make_wformat_args(42)),
+               as_string(L"42µ"));
+  EXPECT_WRITE(stderr, fmt::vprint(stderr, L"{}", fmt::make_wformat_args(42)),
+               as_string(L"42"));
 }
 
 TEST(module_test, named_args) {
@@ -284,9 +271,7 @@ TEST(module_test, named_args) {
 TEST(module_test, literals) {
   using namespace fmt::literals;
   EXPECT_EQ("42", fmt::format("{answer}", "answer"_a = 42));
-  EXPECT_EQ("42", "{}"_format(42));
   EXPECT_EQ(L"42", fmt::format(L"{answer}", L"answer"_a = 42));
-  EXPECT_EQ(L"42", L"{}"_format(42));
 }
 
 TEST(module_test, locale) {
@@ -320,7 +305,7 @@ TEST(module_test, string_view) {
 
 TEST(module_test, memory_buffer) {
   fmt::basic_memory_buffer<char, fmt::inline_buffer_size> buffer;
-  fmt::format_to(buffer, "{}", "42");
+  fmt::format_to(std::back_inserter(buffer), "{}", "42");
   EXPECT_EQ("42", to_string(buffer));
   fmt::memory_buffer nbuffer(std::move(buffer));
   EXPECT_EQ("42", to_string(nbuffer));
@@ -395,27 +380,20 @@ struct test_formatter : fmt::formatter<char> {
   bool check() { return true; }
 };
 
-struct test_dynamic_formatter : fmt::dynamic_formatter<> {
-  bool check() { return true; }
-};
-
-TEST(module_test, formatter) {
-  EXPECT_TRUE(test_formatter{}.check());
-  EXPECT_TRUE(test_dynamic_formatter{}.check());
-}
+TEST(module_test, formatter) { EXPECT_TRUE(test_formatter{}.check()); }
 
 TEST(module_test, join) {
   int arr[3] = {1, 2, 3};
   std::vector<double> vec{1.0, 2.0, 3.0};
   std::initializer_list<int> il{1, 2, 3};
-  auto sep = fmt::to_string_view(", ");
+  auto sep = fmt::string_view(", ");
   EXPECT_EQ("1, 2, 3", to_string(fmt::join(arr + 0, arr + 3, sep)));
   EXPECT_EQ("1, 2, 3", to_string(fmt::join(arr, sep)));
   EXPECT_EQ("1, 2, 3", to_string(fmt::join(vec.begin(), vec.end(), sep)));
   EXPECT_EQ("1, 2, 3", to_string(fmt::join(vec, sep)));
   EXPECT_EQ("1, 2, 3", to_string(fmt::join(il, sep)));
 
-  auto wsep = fmt::to_string_view(L", ");
+  auto wsep = fmt::wstring_view(L", ");
   EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(arr + 0, arr + 3, wsep)));
   EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(arr, wsep)));
   EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(il, wsep)));
@@ -426,7 +404,6 @@ TEST(module_test, time) {
   EXPECT_TRUE(fmt::localtime(time_now).tm_year > 120);
   EXPECT_TRUE(fmt::gmtime(time_now).tm_year > 120);
   auto chrono_now = std::chrono::system_clock::now();
-  EXPECT_TRUE(fmt::localtime(chrono_now).tm_year > 120);
   EXPECT_TRUE(fmt::gmtime(chrono_now).tm_year > 120);
 }
 
@@ -453,34 +430,16 @@ TEST(module_test, weekday) {
   EXPECT_EQ("Mon", fmt::format(std::locale::classic(), "{}", fmt::weekday(1)));
 }
 
-TEST(module_test, to_string_view) {
-  using fmt::to_string_view;
-  fmt::string_view nsv{to_string_view("42")};
-  EXPECT_EQ("42", nsv);
-  fmt::wstring_view wsv{to_string_view(L"42")};
-  EXPECT_EQ(L"42", wsv);
-}
-
 TEST(module_test, printf) {
   EXPECT_WRITE(stdout, fmt::printf("%f", 42.123456), "42.123456");
   EXPECT_WRITE(stdout, fmt::printf("%d", 42), "42");
-  if (false) {
-    EXPECT_WRITE(stdout, fmt::printf(L"%f", 42.123456),
-                 as_string(L"42.123456"));
-    EXPECT_WRITE(stdout, fmt::printf(L"%d", 42), as_string(L"42"));
-  }
+  EXPECT_WRITE(stdout, fmt::printf(L"%f", 42.123456), as_string(L"42.123456"));
+  EXPECT_WRITE(stdout, fmt::printf(L"%d", 42), as_string(L"42"));
 }
 
 TEST(module_test, fprintf) {
   EXPECT_WRITE(stderr, fmt::fprintf(stderr, "%d", 42), "42");
-  std::ostringstream os;
-  fmt::fprintf(os, "%s", "bla");
-  EXPECT_EQ("bla", os.str());
-
   EXPECT_WRITE(stderr, fmt::fprintf(stderr, L"%d", 42), as_string(L"42"));
-  std::wostringstream ws;
-  fmt::fprintf(ws, L"%s", L"bla");
-  EXPECT_EQ(L"bla", ws.str());
 }
 
 TEST(module_test, sprintf) {
@@ -490,25 +449,15 @@ TEST(module_test, sprintf) {
 
 TEST(module_test, vprintf) {
   EXPECT_WRITE(stdout, fmt::vprintf("%d", fmt::make_printf_args(42)), "42");
-  if (false) {
-    EXPECT_WRITE(stdout, fmt::vprintf(L"%d", fmt::make_wprintf_args(42)),
-                 as_string(L"42"));
-  }
+  EXPECT_WRITE(stdout, fmt::vprintf(L"%d", fmt::make_wprintf_args(42)),
+               as_string(L"42"));
 }
 
 TEST(module_test, vfprintf) {
   auto args = fmt::make_printf_args(42);
   EXPECT_WRITE(stderr, fmt::vfprintf(stderr, "%d", args), "42");
-  std::ostringstream os;
-  fmt::vfprintf(os, "%d", args);
-  EXPECT_EQ("42", os.str());
   auto wargs = fmt::make_wprintf_args(42);
-  if (false) {
-    EXPECT_WRITE(stderr, fmt::vfprintf(stderr, L"%d", wargs), as_string(L"42"));
-  }
-  std::wostringstream ws;
-  fmt::vfprintf(ws, L"%d", wargs);
-  EXPECT_EQ(L"42", ws.str());
+  EXPECT_WRITE(stderr, fmt::vfprintf(stderr, L"%d", wargs), as_string(L"42"));
 }
 
 TEST(module_test, vsprintf) {
@@ -538,8 +487,13 @@ TEST(module_test, buffered_file) {
 }
 
 TEST(module_test, output_file) {
+#ifdef __clang__
+  fmt::println("\033[0;33m[=disabled=] {}\033[0;0m",
+               "Clang 16.0 emits multiple copies of vtables");
+#else
   fmt::ostream out = fmt::output_file("module-test", fmt::buffer_size = 1);
   out.close();
+#endif
 }
 
 struct custom_context {
@@ -552,21 +506,15 @@ TEST(module_test, custom_context) {
   EXPECT_TRUE(!custom_arg);
 }
 
-struct disabled_formatter {};
-
-TEST(module_test, has_formatter) {
-  EXPECT_FALSE(
-      (fmt::has_formatter<disabled_formatter, fmt::format_context>::value));
-}
-
-TEST(module_test, is_formattable) {
-  EXPECT_FALSE(fmt::is_formattable<disabled_formatter>::value);
-}
-
 TEST(module_test, compile_format_string) {
   using namespace fmt::literals;
+#ifdef __clang__
+  fmt::println("\033[0;33m[=disabled=] {}\033[0;0m",
+               "Clang 16.0 fails to import user-defined literals");
+#else
   EXPECT_EQ("42", fmt::format("{0:x}"_cf, 0x42));
   EXPECT_EQ(L"42", fmt::format(L"{:}"_cf, 42));
   EXPECT_EQ("4.2", fmt::format("{arg:3.1f}"_cf, "arg"_a = 4.2));
   EXPECT_EQ(L" 42", fmt::format(L"{arg:>3}"_cf, L"arg"_a = L"42"));
+#endif
 }

test/os-test.cc

@@ -22,60 +22,6 @@ using wstring_view = fmt::basic_string_view<wchar_t>;
 
 #  include <windows.h>
 
-TEST(util_test, utf16_to_utf8) {
-  auto s = std::string("ёжик");
-  fmt::detail::utf16_to_utf8 u(L"\x0451\x0436\x0438\x043A");
-  EXPECT_EQ(s, u.str());
-  EXPECT_EQ(s.size(), u.size());
-}
-
-TEST(util_test, utf16_to_utf8_empty_string) {
-  std::string s = "";
-  fmt::detail::utf16_to_utf8 u(L"");
-  EXPECT_EQ(s, u.str());
-  EXPECT_EQ(s.size(), u.size());
-}
-
-template <typename Converter, typename Char>
-void check_utf_conversion_error(const char* message,
-                                fmt::basic_string_view<Char> str =
-                                    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());
-  try {
-    (Converter)(str);
-  } catch (const std::system_error& e) {
-    error = e;
-  }
-  EXPECT_EQ(ERROR_INVALID_PARAMETER, error.code().value());
-  EXPECT_THAT(error.what(), HasSubstr(fmt::to_string(out)));
-}
-
-TEST(util_test, utf16_to_utf8_error) {
-  check_utf_conversion_error<fmt::detail::utf16_to_utf8, wchar_t>(
-      "cannot convert string from UTF-16 to UTF-8");
-}
-
-TEST(util_test, utf16_to_utf8_convert) {
-  fmt::detail::utf16_to_utf8 u;
-  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)));
-}
-
-TEST(os_test, format_std_error_code) {
-  EXPECT_EQ("generic:42",
-            fmt::format(FMT_STRING("{0}"),
-                        std::error_code(42, std::generic_category())));
-  EXPECT_EQ("system:42",
-            fmt::format(FMT_STRING("{0}"),
-                        std::error_code(42, fmt::system_category())));
-  EXPECT_EQ("system:-42",
-            fmt::format(FMT_STRING("{0}"),
-                        std::error_code(-42, fmt::system_category())));
-}
-
 TEST(os_test, format_windows_error) {
   LPWSTR message = nullptr;
   auto result = FormatMessageW(
@@ -83,7 +29,8 @@ TEST(os_test, format_windows_error) {
           FORMAT_MESSAGE_IGNORE_INSERTS,
       nullptr, ERROR_FILE_EXISTS, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
       reinterpret_cast<LPWSTR>(&message), 0, nullptr);
-  fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
+  fmt::detail::unicode_to_utf8<wchar_t> utf8_message(
+      wstring_view(message, result - 2));
   LocalFree(message);
   fmt::memory_buffer actual_message;
   fmt::detail::format_windows_error(actual_message, ERROR_FILE_EXISTS, "test");
@@ -108,7 +55,8 @@ TEST(os_test, format_long_windows_error) {
     LocalFree(message);
     return;
   }
-  fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
+  fmt::detail::unicode_to_utf8<wchar_t> utf8_message(
+      wstring_view(message, result - 2));
   LocalFree(message);
   fmt::memory_buffer actual_message;
   fmt::detail::format_windows_error(actual_message, provisioning_not_allowed,
@@ -139,6 +87,17 @@ TEST(os_test, report_windows_error) {
                fmt::to_string(out));
 }
 
+#  if FMT_USE_FCNTL && !defined(__MINGW32__)
+TEST(file_test, open_windows_file) {
+  using fmt::file;
+  file out = file::open_windows_file(L"test-file",
+                                     file::WRONLY | file::CREATE | file::TRUNC);
+  out.write("x", 1);
+  file in = file::open_windows_file(L"test-file", file::RDONLY);
+  EXPECT_READ(in, "x");
+}
+#  endif  // FMT_USE_FCNTL && !defined(__MINGW32__)
+
 #endif  // _WIN32
 
 #if FMT_USE_FCNTL

test/ostream-test.cc

@@ -86,13 +86,13 @@ 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_THROW_MSG((void)fmt::format(runtime("{0:+}"), test_string()),
-                   format_error, "format specifier requires numeric argument");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), test_string()),
-                   format_error, "format specifier requires numeric argument");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), test_string()),
-                   format_error, "format specifier requires numeric argument");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), test_string()),
-                   format_error, "format specifier requires numeric argument");
+                   format_error, "invalid format specifier");
   EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), test_string()),
                    format_error, "format specifier requires numeric argument");
   EXPECT_EQ("test         ", fmt::format("{0:13}", test_string("test")));
@@ -106,9 +106,17 @@ TEST(ostream_test, empty_custom_output) {
 }
 
 TEST(ostream_test, print) {
-  std::ostringstream os;
-  fmt::print(os, "Don't {}!", "panic");
-  EXPECT_EQ("Don't panic!", os.str());
+  {
+    std::ostringstream os;
+    fmt::print(os, "Don't {}!", "panic");
+    EXPECT_EQ("Don't panic!", os.str());
+  }
+
+  {
+    std::ostringstream os;
+    fmt::println(os, "Don't {}!", "panic");
+    EXPECT_EQ("Don't panic!\n", os.str());
+  }
 }
 
 TEST(ostream_test, write_to_ostream) {
@@ -132,7 +140,7 @@ TEST(ostream_test, write_to_ostream_max_size) {
   } buffer(max_size);
 
   struct mock_streambuf : std::streambuf {
-    MOCK_METHOD2(xsputn, std::streamsize(const void* s, std::streamsize n));
+    MOCK_METHOD(std::streamsize, xsputn, (const void*, std::streamsize));
     auto xsputn(const char* s, std::streamsize n) -> std::streamsize override {
       const void* v = s;
       return xsputn(v, n);
@@ -218,45 +226,6 @@ TEST(ostream_test, format_to_n) {
   EXPECT_EQ("xabx", fmt::string_view(buffer, 4));
 }
 
-template <typename T> struct convertible {
-  T value;
-  explicit convertible(const T& val) : value(val) {}
-  operator T() const { return value; }
-};
-
-TEST(ostream_test, disable_builtin_ostream_operators) {
-  EXPECT_EQ("42", fmt::format("{:d}", convertible<unsigned short>(42)));
-  EXPECT_EQ("foo", fmt::format("{}", convertible<const char*>("foo")));
-}
-
-struct streamable_and_convertible_to_bool {
-  operator bool() const { return true; }
-};
-
-std::ostream& operator<<(std::ostream& os, streamable_and_convertible_to_bool) {
-  return os << "foo";
-}
-
-TEST(ostream_test, format_convertible_to_bool) {
-  // operator<< is intentionally not used because of potential ODR violations.
-  EXPECT_EQ(fmt::format("{}", streamable_and_convertible_to_bool()), "true");
-}
-
-struct streamable_and_convertible_to_string_view {
-  operator fmt::string_view() const { return "foo"; }
-};
-
-std::ostream& operator<<(std::ostream& os,
-                         streamable_and_convertible_to_string_view) {
-  return os << "bar";
-}
-
-TEST(ostream_test, format_convertible_to_string_vew) {
-  // operator<< is intentionally not used because of potential ODR violations.
-  EXPECT_EQ(fmt::format("{}", streamable_and_convertible_to_string_view()),
-            "foo");
-}
-
 struct copyfmt_test {};
 
 std::ostream& operator<<(std::ostream& os, copyfmt_test) {

test/posix-mock-test.cc

@@ -72,12 +72,6 @@ int test::open(const char* path, int oflag, int mode) {
   EMULATE_EINTR(open, -1);
   return ::open(path, oflag, mode);
 }
-#else
-errno_t test::sopen_s(int* pfh, const char* filename, int oflag, int shflag,
-                      int pmode) {
-  EMULATE_EINTR(open, EINTR);
-  return _sopen_s(pfh, filename, oflag, shflag, pmode);
-}
 #endif
 
 #ifndef _WIN32
@@ -220,11 +214,11 @@ TEST(os_test, getpagesize) {
 }
 
 TEST(file_test, open_retry) {
+#  ifndef _WIN32
   write_file("temp", "there must be something here");
   std::unique_ptr<file> f{nullptr};
   EXPECT_RETRY(f.reset(new file("temp", file::RDONLY)), open,
                "cannot open file temp");
-#  ifndef _WIN32
   char c = 0;
   f->read(&c, 1);
 #  endif

test/posix-mock.h

@@ -37,8 +37,6 @@ int fstat(int fd, struct stat* buf);
 #else
 typedef unsigned size_t;
 typedef int ssize_t;
-errno_t sopen_s(int* pfh, const char* filename, int oflag, int shflag,
-                int pmode);
 #endif
 
 #ifndef _WIN32

test/printf-test.cc

@@ -225,10 +225,8 @@ TEST(printf_test, hash_flag) {
   EXPECT_PRINTF("-42.0000", "%#g", -42.0);
   EXPECT_PRINTF("-42.0000", "%#G", -42.0);
 
-  safe_sprintf(buffer, "%#a", 16.0);
-  EXPECT_PRINTF(buffer, "%#a", 16.0);
-  safe_sprintf(buffer, "%#A", 16.0);
-  EXPECT_PRINTF(buffer, "%#A", 16.0);
+  EXPECT_PRINTF("0x1.p+4", "%#a", 16.0);
+  EXPECT_PRINTF("0X1.P+4", "%#A", 16.0);
 
   // '#' flag is ignored for non-numeric types.
   EXPECT_PRINTF("x", "%#c", 'x');
@@ -239,7 +237,7 @@ TEST(printf_test, width) {
 
   // Width cannot be specified twice.
   EXPECT_THROW_MSG(test_sprintf("%5-5d", 42), format_error,
-                   "invalid type specifier");
+                   "invalid format specifier");
 
   EXPECT_THROW_MSG(test_sprintf(format("%{}d", big_num), 42), format_error,
                    "number is too big");
@@ -407,10 +405,7 @@ TEST(printf_test, length) {
   EXPECT_PRINTF(fmt::format("{:.6}", max), "%Lg", max);
 }
 
-TEST(printf_test, bool) {
-  EXPECT_PRINTF("1", "%d", true);
-  EXPECT_PRINTF("true", "%s", true);
-}
+TEST(printf_test, bool) { EXPECT_PRINTF("1", "%d", true); }
 
 TEST(printf_test, int) {
   EXPECT_PRINTF("-42", "%d", -42);

test/ranges-test.cc

@@ -12,6 +12,8 @@
 #include "fmt/ranges.h"
 
 #include <map>
+#include <queue>
+#include <stack>
 #include <string>
 #include <vector>
 
@@ -50,6 +52,14 @@ TEST(ranges_test, format_vector) {
   EXPECT_EQ(fmt::format("{}", v), "[1, 2, 3, 5, 7, 11]");
   EXPECT_EQ(fmt::format("{::#x}", v), "[0x1, 0x2, 0x3, 0x5, 0x7, 0xb]");
   EXPECT_EQ(fmt::format("{:n:#x}", v), "0x1, 0x2, 0x3, 0x5, 0x7, 0xb");
+
+  auto vc = std::vector<char>{'a', 'b', 'c'};
+  auto vvc = std::vector<std::vector<char>>{vc, vc};
+  EXPECT_EQ(fmt::format("{}", vc), "['a', 'b', 'c']");
+  EXPECT_EQ(fmt::format("{}", vvc), "[['a', 'b', 'c'], ['a', 'b', 'c']]");
+  EXPECT_EQ(fmt::format("{:n}", vvc), "['a', 'b', 'c'], ['a', 'b', 'c']");
+  EXPECT_EQ(fmt::format("{:n:n}", vvc), "'a', 'b', 'c', 'a', 'b', 'c'");
+  EXPECT_EQ(fmt::format("{:n:n:}", vvc), "a, b, c, a, b, c");
 }
 
 TEST(ranges_test, format_vector2) {
@@ -96,6 +106,7 @@ TEST(ranges_test, format_tuple) {
   auto t =
       std::tuple<int, float, std::string, char>(42, 1.5f, "this is tuple", 'i');
   EXPECT_EQ(fmt::format("{}", t), "(42, 1.5, \"this is tuple\", 'i')");
+
   EXPECT_EQ(fmt::format("{}", std::tuple<>()), "()");
 
   EXPECT_TRUE((fmt::is_formattable<std::tuple<>>::value));
@@ -108,6 +119,25 @@ TEST(ranges_test, format_tuple) {
   EXPECT_TRUE((fmt::is_formattable<std::tuple<int, float>>::value));
 }
 
+struct not_default_formattable {};
+struct bad_format {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<not_default_formattable> {
+  auto parse(format_parse_context&) -> const char* { throw bad_format(); }
+  auto format(not_default_formattable, format_context& ctx)
+      -> format_context::iterator {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(ranges_test, tuple_parse_calls_element_parse) {
+  auto f = fmt::formatter<std::tuple<not_default_formattable>>();
+  auto ctx = fmt::format_parse_context("");
+  EXPECT_THROW(f.parse(ctx), bad_format);
+}
+
 #ifdef FMT_RANGES_TEST_ENABLE_FORMAT_STRUCT
 struct tuple_like {
   int i;
@@ -149,32 +179,24 @@ TEST(ranges_test, format_to) {
   EXPECT_STREQ(buf, "[1, 2, 3]");
 }
 
-struct path_like {
+template <typename Char> struct path_like {
   const path_like* begin() const;
   const path_like* end() const;
 
-  operator std::string() const;
+  operator std::basic_string<Char>() const;
 };
 
-TEST(ranges_test, path_like) {
-  EXPECT_FALSE((fmt::is_range<path_like, char>::value));
+TEST(ranges_test, disabled_range_formatting_of_path) {
+  // Range formatting of path is disabled because of infinite recursion
+  // (path element is itself a path).
+  EXPECT_EQ((fmt::range_format_kind<path_like<char>, char>::value),
+            fmt::range_format::disabled);
+  EXPECT_EQ((fmt::range_format_kind<path_like<wchar_t>, char>::value),
+            fmt::range_format::disabled);
 }
 
-#ifdef FMT_USE_STRING_VIEW
-struct string_like {
-  const char* begin();
-  const char* end();
-  operator fmt::string_view() const { return "foo"; }
-  operator std::string_view() const { return "foo"; }
-};
-
-TEST(ranges_test, format_string_like) {
-  EXPECT_EQ(fmt::format("{}", string_like()), "foo");
-}
-#endif  // FMT_USE_STRING_VIEW
-
-// A range that provides non-const only begin()/end() to test fmt::join handles
-// that.
+// A range that provides non-const only begin()/end() to test fmt::join
+// handles that.
 //
 // Some ranges (e.g. those produced by range-v3's views::filter()) can cache
 // information during iteration so they only provide non-const begin()/end().
@@ -198,7 +220,7 @@ template <typename T> class noncopyable_range {
   std::vector<T> vec;
 
  public:
-  using const_iterator = typename ::std::vector<T>::const_iterator;
+  using iterator = typename ::std::vector<T>::iterator;
 
   template <typename... Args>
   explicit noncopyable_range(Args&&... args)
@@ -207,8 +229,8 @@ template <typename T> class noncopyable_range {
   noncopyable_range(noncopyable_range const&) = delete;
   noncopyable_range(noncopyable_range&) = delete;
 
-  const_iterator begin() const { return vec.begin(); }
-  const_iterator end() const { return vec.end(); }
+  iterator begin() { return vec.begin(); }
+  iterator end() { return vec.end(); }
 };
 
 TEST(ranges_test, range) {
@@ -237,7 +259,6 @@ TEST(ranges_test, enum_range) {
 }
 
 #if !FMT_MSC_VERSION
-
 TEST(ranges_test, unformattable_range) {
   EXPECT_FALSE((fmt::has_formatter<std::vector<unformattable>,
                                    fmt::format_context>::value));
@@ -369,7 +390,7 @@ TEST(ranges_test, is_printable) {
   EXPECT_FALSE(is_printable(0x110000));
 }
 
-TEST(ranges_test, escape_string) {
+TEST(ranges_test, escape) {
   using vec = std::vector<std::string>;
   EXPECT_EQ(fmt::format("{}", vec{"\n\r\t\"\\"}), "[\"\\n\\r\\t\\\"\\\\\"]");
   EXPECT_EQ(fmt::format("{}", vec{"\x07"}), "[\"\\x07\"]");
@@ -389,20 +410,13 @@ TEST(ranges_test, escape_string) {
               "[\"\\xf0(\\x00\\x00anything\"]");
 
     // Correct utf-8.
-    EXPECT_EQ(fmt::format("{}", vec{"понедельник"}), "[\"понедельник\"]");
+    EXPECT_EQ(fmt::format("{}", vec{"🦄"}), "[\"🦄\"]");
   }
-}
 
-#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\"]");
+  EXPECT_EQ(fmt::format("{}", std::vector<std::vector<char>>{{'x'}}),
+            "[['x']]");
+  EXPECT_EQ(fmt::format("{}", std::tuple<std::vector<char>>{{'x'}}), "(['x'])");
 }
-#endif  // FMT_USE_STRING_VIEW
 
 template <typename R> struct fmt_ref_view {
   R* r;
@@ -422,3 +436,62 @@ TEST(ranges_test, range_of_range_of_mixed_const) {
 TEST(ranges_test, vector_char) {
   EXPECT_EQ(fmt::format("{}", std::vector<char>{'a', 'b'}), "['a', 'b']");
 }
+
+TEST(ranges_test, container_adaptor) {
+  {
+    using fmt::detail::is_container_adaptor_like;
+    using T = std::nullptr_t;
+    static_assert(is_container_adaptor_like<std::stack<T>>::value, "");
+    static_assert(is_container_adaptor_like<std::queue<T>>::value, "");
+    static_assert(is_container_adaptor_like<std::priority_queue<T>>::value, "");
+    static_assert(!is_container_adaptor_like<std::vector<T>>::value, "");
+  }
+
+  {
+    auto s = std::stack<int>();
+    s.push(1);
+    s.push(2);
+    EXPECT_EQ(fmt::format("{}", s), "[1, 2]");
+    EXPECT_EQ(fmt::format("{}", const_cast<const decltype(s)&>(s)), "[1, 2]");
+  }
+
+  {
+    auto q = std::queue<int>();
+    q.push(1);
+    q.push(2);
+    EXPECT_EQ(fmt::format("{}", q), "[1, 2]");
+  }
+
+  {
+    auto q = std::priority_queue<int>();
+    q.push(3);
+    q.push(1);
+    q.push(2);
+    q.push(4);
+    EXPECT_EQ(fmt::format("{}", q), "[4, 3, 2, 1]");
+  }
+
+  {
+    auto s = std::stack<char, std::string>();
+    s.push('a');
+    s.push('b');
+    // See https://cplusplus.github.io/LWG/issue3881.
+    EXPECT_EQ(fmt::format("{}", s), "['a', 'b']");
+  }
+
+  {
+    struct my_container_adaptor {
+      using value_type = int;
+      using container_type = std::vector<value_type>;
+      void push(const value_type& v) { c.push_back(v); }
+
+     protected:
+      container_type c;
+    };
+
+    auto m = my_container_adaptor();
+    m.push(1);
+    m.push(2);
+    EXPECT_EQ(fmt::format("{}", m), "[1, 2]");
+  }
+}

test/scan-test.cc

@@ -65,7 +65,7 @@ TEST(scan_test, read_string_view) {
   EXPECT_EQ(s, "foo");
 }
 
-#ifndef _WIN32
+#ifdef FMT_HAVE_STRPTIME
 namespace fmt {
 template <> struct scanner<tm> {
   std::string format;

test/scan.h

@@ -42,7 +42,7 @@ struct scan_context {
  public:
   using iterator = const char*;
 
-  explicit scan_context(string_view input) : input_(input) {}
+  explicit FMT_CONSTEXPR scan_context(string_view input) : input_(input) {}
 
   iterator begin() const { return input_.data(); }
   iterator end() const { return begin() + input_.size(); }
@@ -83,17 +83,21 @@ class scan_arg {
     // TODO: more types
   };
 
-  scan_arg() : type(scan_type::none_type) {}
-  scan_arg(int& value) : type(scan_type::int_type), int_value(&value) {}
-  scan_arg(unsigned& value) : type(scan_type::uint_type), uint_value(&value) {}
-  scan_arg(long long& value)
+  FMT_CONSTEXPR scan_arg() : type(scan_type::none_type), int_value(nullptr) {}
+  FMT_CONSTEXPR scan_arg(int& value)
+      : type(scan_type::int_type), int_value(&value) {}
+  FMT_CONSTEXPR scan_arg(unsigned& value)
+      : type(scan_type::uint_type), uint_value(&value) {}
+  FMT_CONSTEXPR scan_arg(long long& value)
       : type(scan_type::long_long_type), long_long_value(&value) {}
-  scan_arg(unsigned long long& value)
+  FMT_CONSTEXPR scan_arg(unsigned long long& value)
       : type(scan_type::ulong_long_type), ulong_long_value(&value) {}
-  scan_arg(std::string& value) : type(scan_type::string_type), string(&value) {}
-  scan_arg(fmt::string_view& value)
+  FMT_CONSTEXPR scan_arg(std::string& value)
+      : type(scan_type::string_type), string(&value) {}
+  FMT_CONSTEXPR scan_arg(fmt::string_view& value)
       : type(scan_type::string_view_type), string_view(&value) {}
-  template <typename T> scan_arg(T& value) : type(scan_type::custom_type) {
+  template <typename T>
+  FMT_CONSTEXPR scan_arg(T& value) : type(scan_type::custom_type) {
     custom.value = &value;
     custom.scan = scan_custom_arg<T>;
   }
@@ -114,7 +118,7 @@ struct scan_args {
   const detail::scan_arg* data;
 
   template <size_t N>
-  scan_args(const std::array<detail::scan_arg, N>& store)
+  FMT_CONSTEXPR scan_args(const std::array<detail::scan_arg, N>& store)
       : size(N), data(store.data()) {
     static_assert(N < INT_MAX, "too many arguments");
   }
@@ -154,7 +158,8 @@ struct scan_handler : error_handler {
   }
 
  public:
-  scan_handler(string_view format, string_view input, scan_args args)
+  FMT_CONSTEXPR scan_handler(string_view format, string_view input,
+                             scan_args args)
       : parse_ctx_(format), scan_ctx_(input), args_(args), next_arg_id_(0) {}
 
   const char* pos() const { return scan_ctx_.begin(); }

test/static-export-test/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.18)
+cmake_minimum_required(VERSION 3.8...3.25)
 
 project(fmt-link CXX)
 

test/std-test.cc

@@ -6,47 +6,108 @@
 // For the license information refer to format.h.
 
 #include "fmt/std.h"
-#include "fmt/ranges.h"
 
+#include <stdexcept>
 #include <string>
 #include <vector>
 
-#include "gtest/gtest.h"
+#include "fmt/os.h"  // fmt::system_category
+#include "fmt/ranges.h"
+#include "gtest-extra.h"  // StartsWith
+
+using testing::StartsWith;
 
-TEST(std_test, path) {
 #ifdef __cpp_lib_filesystem
+TEST(std_test, path) {
   EXPECT_EQ(fmt::format("{:8}", std::filesystem::path("foo")), "\"foo\"   ");
   EXPECT_EQ(fmt::format("{}", std::filesystem::path("foo\"bar.txt")),
             "\"foo\\\"bar.txt\"");
+  EXPECT_EQ(fmt::format("{:?}", std::filesystem::path("foo\"bar.txt")),
+            "\"foo\\\"bar.txt\"");
 
 #  ifdef _WIN32
-  // File.txt in Russian.
-  const wchar_t unicode_path[] = {0x424, 0x430, 0x439, 0x43b, 0x2e,
-                                  0x74,  0x78,  0x74,  0};
-  const char unicode_u8path[] = {'"',        char(0xd0), char(0xa4), char(0xd0),
-                                 char(0xb0), char(0xd0), char(0xb9), char(0xd0),
-                                 char(0xbb), '.',        't',        'x',
-                                 't',        '"',        '\0'};
-  EXPECT_EQ(fmt::format("{}", std::filesystem::path(unicode_path)),
-            unicode_u8path);
+  EXPECT_EQ(fmt::format("{}", std::filesystem::path(
+                                  L"\x0428\x0447\x0443\x0447\x044B\x043D\x0448"
+                                  L"\x0447\x044B\x043D\x0430")),
+            "\"Шчучыншчына\"");
+  EXPECT_EQ(fmt::format("{}", std::filesystem::path(L"\xd800")), "\"\\ud800\"");
 #  endif
-#endif
 }
 
-TEST(ranges_std_test, format_vector_path) {
 // Test ambiguity problem described in #2954.
-#ifdef __cpp_lib_filesystem
+TEST(ranges_std_test, format_vector_path) {
   auto p = std::filesystem::path("foo/bar.txt");
   auto c = std::vector<std::string>{"abc", "def"};
   EXPECT_EQ(fmt::format("path={}, range={}", p, c),
             "path=\"foo/bar.txt\", range=[\"abc\", \"def\"]");
-#endif
 }
 
+// Test that path is not escaped twice in the debug mode.
+TEST(ranges_std_test, format_quote_path) {
+  auto vec =
+      std::vector<std::filesystem::path>{"path1/file1.txt", "path2/file2.txt"};
+  EXPECT_EQ(fmt::format("{}", vec),
+            "[\"path1/file1.txt\", \"path2/file2.txt\"]");
+#  ifdef __cpp_lib_optional
+  auto o = std::optional<std::filesystem::path>("path/file.txt");
+  EXPECT_EQ(fmt::format("{}", o), "optional(\"path/file.txt\")");
+  EXPECT_EQ(fmt::format("{:?}", o), "optional(\"path/file.txt\")");
+#  endif
+}
+#endif
+
 TEST(std_test, thread_id) {
   EXPECT_FALSE(fmt::format("{}", std::this_thread::get_id()).empty());
 }
 
+TEST(std_test, optional) {
+#ifdef __cpp_lib_optional
+  EXPECT_EQ(fmt::format("{}", std::optional<int>{}), "none");
+  EXPECT_EQ(fmt::format("{}", std::pair{1, "second"}), "(1, \"second\")");
+  EXPECT_EQ(fmt::format("{}", std::vector{std::optional{1}, std::optional{2},
+                                          std::optional{3}}),
+            "[optional(1), optional(2), optional(3)]");
+  EXPECT_EQ(
+      fmt::format("{}", std::optional<std::optional<const char*>>{{"nested"}}),
+      "optional(optional(\"nested\"))");
+  EXPECT_EQ(
+      fmt::format("{:<{}}", std::optional{std::string{"left aligned"}}, 30),
+      "optional(\"left aligned\"                )");
+  EXPECT_EQ(
+      fmt::format("{::d}", std::optional{std::vector{'h', 'e', 'l', 'l', 'o'}}),
+      "optional([104, 101, 108, 108, 111])");
+  EXPECT_EQ(fmt::format("{}", std::optional{std::string{"string"}}),
+            "optional(\"string\")");
+  EXPECT_EQ(fmt::format("{}", std::optional{'C'}), "optional(\'C\')");
+  EXPECT_EQ(fmt::format("{:.{}f}", std::optional{3.14}, 1), "optional(3.1)");
+
+  struct unformattable {};
+  EXPECT_FALSE((fmt::is_formattable<unformattable>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::optional<unformattable>>::value));
+  EXPECT_TRUE((fmt::is_formattable<std::optional<int>>::value));
+#endif
+}
+
+struct throws_on_move {
+  throws_on_move() = default;
+
+  [[noreturn]] throws_on_move(throws_on_move&&) {
+    throw std::runtime_error("Thrown by throws_on_move");
+  }
+
+  throws_on_move(const throws_on_move&) = default;
+};
+
+namespace fmt {
+template <> struct formatter<throws_on_move> : formatter<string_view> {
+  auto format(const throws_on_move&, format_context& ctx) const
+      -> decltype(ctx.out()) {
+    string_view str("<throws_on_move>");
+    return formatter<string_view>::format(str, ctx);
+  }
+};
+}  // namespace fmt
+
 TEST(std_test, variant) {
 #ifdef __cpp_lib_variant
   EXPECT_EQ(fmt::format("{}", std::monostate{}), "monostate");
@@ -75,5 +136,86 @@ TEST(std_test, variant) {
 
   EXPECT_EQ(fmt::format("{}", v4), "variant(monostate)");
   EXPECT_EQ(fmt::format("{}", v5), "variant(\"yes, this is variant\")");
+
+  volatile int i = 42;  // Test compile error before GCC 11 described in #3068.
+  EXPECT_EQ(fmt::format("{}", i), "42");
+
+  std::variant<std::monostate, throws_on_move> v6;
+
+  try {
+    throws_on_move thrower;
+    v6.emplace<throws_on_move>(std::move(thrower));
+  } catch (const std::runtime_error&) {
+  }
+  // v6 is now valueless by exception
+
+  EXPECT_EQ(fmt::format("{}", v6), "variant(valueless by exception)");
+
+#endif
+}
+
+TEST(std_test, error_code) {
+  EXPECT_EQ("generic:42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(42, std::generic_category())));
+  EXPECT_EQ("system:42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(42, fmt::system_category())));
+  EXPECT_EQ("system:-42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(-42, fmt::system_category())));
+}
+
+template <typename Catch> void exception_test() {
+  try {
+    throw std::runtime_error("Test Exception");
+  } catch (const Catch& ex) {
+    EXPECT_EQ("Test Exception", fmt::format("{}", ex));
+    EXPECT_EQ("std::runtime_error: Test Exception", fmt::format("{:t}", ex));
+  }
+}
+
+namespace my_ns1 {
+namespace my_ns2 {
+struct my_exception : public std::exception {
+ private:
+  std::string msg;
+
+ public:
+  my_exception(const std::string& s) : msg(s) {}
+  const char* what() const noexcept override;
+};
+const char* my_exception::what() const noexcept { return msg.c_str(); }
+}  // namespace my_ns2
+}  // namespace my_ns1
+
+TEST(std_test, exception) {
+  exception_test<std::exception>();
+  exception_test<std::runtime_error>();
+
+  try {
+    using namespace my_ns1::my_ns2;
+    throw my_exception("My Exception");
+  } catch (const std::exception& ex) {
+    EXPECT_EQ("my_ns1::my_ns2::my_exception: My Exception",
+              fmt::format("{:t}", ex));
+    EXPECT_EQ("My Exception", fmt::format("{:}", ex));
+  }
+
+  try {
+    throw std::system_error(std::error_code(), "message");
+  } catch (const std::system_error& ex) {
+    EXPECT_THAT(fmt::format("{:t}", ex), StartsWith("std::system_error: "));
+  }
+
+#ifdef __cpp_lib_filesystem
+  // Tests that the inline namespace is stripped out, e.g.
+  // std::filesystem::__cxx11::* -> std::filesystem::*.
+  try {
+    throw std::filesystem::filesystem_error("message", std::error_code());
+  } catch (const std::filesystem::filesystem_error& ex) {
+    EXPECT_THAT(fmt::format("{:t}", ex),
+                StartsWith("std::filesystem::filesystem_error: "));
+  }
 #endif
 }

test/util.h

@@ -10,11 +10,7 @@
 #include <locale>
 #include <string>
 
-#ifdef FMT_MODULE_TEST
-import fmt;
-#else
-#  include "fmt/os.h"
-#endif  // FMT_MODULE_TEST
+#include "fmt/os.h"
 
 #ifdef _MSC_VER
 #  define FMT_VSNPRINTF vsprintf_s
@@ -81,5 +77,5 @@ class date {
   int day() const { return day_; }
 };
 
-// Returns a locale with the given name if available or classic locale othewise.
+// Returns a locale with the given name if available or classic locale otherwise.
 std::locale get_locale(const char* name, const char* alt_name = nullptr);

test/xchar-test.cc

@@ -7,6 +7,7 @@
 
 #include "fmt/xchar.h"
 
+#include <algorithm>
 #include <complex>
 #include <cwchar>
 #include <vector>
@@ -15,31 +16,21 @@
 #include "fmt/color.h"
 #include "fmt/ostream.h"
 #include "fmt/ranges.h"
+#include "fmt/std.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 {
- private:
-  std::basic_string<Char> s_;
-
- public:
-  test_string(const Char* s) : s_(s) {}
-  const Char* data() const { return s_.data(); }
-  size_t length() const { return s_.size(); }
-  operator const Char*() const { return s_.c_str(); }
-};
-
-template <typename Char>
-fmt::basic_string_view<Char> to_string_view(const test_string<Char>& s) {
-  return {s.data(), s.length()};
-}
+#if defined(__MINGW32__) && !defined(_UCRT)
+// Only C89 conversion specifiers when using MSVCRT instead of UCRT
+#  define FMT_HAS_C99_STRFTIME 0
+#else
+#  define FMT_HAS_C99_STRFTIME 1
+#endif
 
 struct non_string {};
-}  // namespace test_ns
 
 template <typename T> class is_string_test : public testing::Test {};
 
@@ -61,8 +52,7 @@ TYPED_TEST(is_string_test, is_string) {
   using fmt_string_view = fmt::detail::std_string_view<TypeParam>;
   EXPECT_TRUE(std::is_empty<fmt_string_view>::value !=
               fmt::detail::is_string<fmt_string_view>::value);
-  EXPECT_TRUE(fmt::detail::is_string<test_ns::test_string<TypeParam>>::value);
-  EXPECT_FALSE(fmt::detail::is_string<test_ns::non_string>::value);
+  EXPECT_FALSE(fmt::detail::is_string<non_string>::value);
 }
 
 // std::is_constructible is broken in MSVC until version 2015.
@@ -112,10 +102,12 @@ struct custom_char {
   template <typename T>
   constexpr custom_char(T val) : value(static_cast<int>(val)) {}
 
-  operator int() const { return value; }
+  operator char() const {
+    return value <= 0xff ? static_cast<char>(value) : '\0';
+  }
 };
 
-int to_ascii(custom_char c) { return c; }
+auto to_ascii(custom_char c) -> char { return c; }
 
 FMT_BEGIN_NAMESPACE
 template <> struct is_char<custom_char> : std::true_type {};
@@ -200,7 +192,10 @@ TEST(xchar_test, named_arg_udl) {
 
 TEST(xchar_test, print) {
   // Check that the wide print overload compiles.
-  if (fmt::detail::const_check(false)) fmt::print(L"test");
+  if (fmt::detail::const_check(false)) {
+    fmt::print(L"test");
+    fmt::println(L"test");
+  }
 }
 
 TEST(xchar_test, join) {
@@ -284,7 +279,8 @@ std::wstring system_wcsftime(const std::wstring& format, const std::tm* timeptr,
 }
 
 TEST(chrono_test_wchar, time_point) {
-  auto t1 = std::chrono::system_clock::now();
+  auto t1 = std::chrono::time_point_cast<std::chrono::seconds>(
+      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",
@@ -292,19 +288,36 @@ TEST(chrono_test_wchar, time_point) {
       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"};
+      L"%EX", L"%D",  L"%F",  L"%R",  L"%T",  L"%p"};
 #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"});
-#elif defined(__MINGW32__) && !defined(_UCRT)
+#elif !FMT_HAS_C99_STRFTIME
   // Only C89 conversion specifiers when using MSVCRT instead of UCRT
   spec_list = {L"%%", L"%Y", L"%y", L"%b", L"%B", L"%m", L"%U",
                L"%W", L"%j", L"%d", L"%a", L"%A", L"%w", L"%H",
-               L"%I", L"%M", L"%S", L"%x", L"%X", L"%p", L"%Z"};
+               L"%I", L"%M", L"%S", L"%x", L"%X", L"%p"};
 #endif
   spec_list.push_back(L"%Y-%m-%d %H:%M:%S");
 
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&t);
+
+    auto sys_output = system_wcsftime(spec, &tm);
+
+    auto fmt_spec = fmt::format(L"{{:{}}}", spec);
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+
+  // Timezone formatters tests makes sense for localtime.
+#if FMT_HAS_C99_STRFTIME
+  spec_list = {L"%z", L"%Z"};
+#else
+  spec_list = {L"%Z"};
+#endif
   for (const auto& spec : spec_list) {
     auto t = std::chrono::system_clock::to_time_t(t1);
     auto tm = *std::localtime(&t);
@@ -312,8 +325,38 @@ TEST(chrono_test_wchar, time_point) {
     auto sys_output = system_wcsftime(spec, &tm);
 
     auto fmt_spec = fmt::format(L"{{:{}}}", spec);
-    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
     EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
+
+    if (spec == L"%z") {
+      sys_output.insert(sys_output.end() - 2, 1, L':');
+      EXPECT_EQ(sys_output, fmt::format(L"{:%Ez}", tm));
+      EXPECT_EQ(sys_output, fmt::format(L"{:%Oz}", tm));
+    }
+  }
+
+  // Separate tests for UTC, since std::time_put can use local time and ignoring
+  // the timezone in std::tm (if it presents on platform).
+  if (fmt::detail::has_member_data_tm_zone<std::tm>::value) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&t);
+
+    std::vector<std::wstring> tz_names = {L"GMT", L"UTC"};
+    EXPECT_THAT(tz_names, Contains(fmt::format(L"{:%Z}", t1)));
+    EXPECT_THAT(tz_names, Contains(fmt::format(L"{:%Z}", tm)));
+  }
+
+  if (fmt::detail::has_member_data_tm_gmtoff<std::tm>::value) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::gmtime(&t);
+
+    EXPECT_EQ(L"+0000", fmt::format(L"{:%z}", t1));
+    EXPECT_EQ(L"+0000", fmt::format(L"{:%z}", tm));
+
+    EXPECT_EQ(L"+00:00", fmt::format(L"{:%Ez}", t1));
+    EXPECT_EQ(L"+00:00", fmt::format(L"{:%Ez}", tm));
+
+    EXPECT_EQ(L"+00:00", fmt::format(L"{:%Oz}", t1));
+    EXPECT_EQ(L"+00:00", fmt::format(L"{:%Oz}", tm));
   }
 }
 
@@ -324,9 +367,17 @@ TEST(xchar_test, color) {
 
 TEST(xchar_test, ostream) {
 #if !FMT_GCC_VERSION || FMT_GCC_VERSION >= 409
-  std::wostringstream wos;
-  fmt::print(wos, L"Don't {}!", L"panic");
-  EXPECT_EQ(wos.str(), L"Don't panic!");
+  {
+    std::wostringstream wos;
+    fmt::print(wos, L"Don't {}!", L"panic");
+    EXPECT_EQ(wos.str(), L"Don't panic!");
+  }
+
+  {
+    std::wostringstream wos;
+    fmt::println(wos, L"Don't {}!", L"panic");
+    EXPECT_EQ(wos.str(), L"Don't panic!\n");
+  }
 #endif
 }
 
@@ -344,6 +395,7 @@ TEST(xchar_test, escape_string) {
 TEST(xchar_test, to_wstring) { EXPECT_EQ(L"42", fmt::to_wstring(42)); }
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+
 template <typename Char> struct numpunct : std::numpunct<Char> {
  protected:
   Char do_decimal_point() const override { return '?'; }
@@ -379,6 +431,9 @@ TEST(locale_test, localized_double) {
   EXPECT_EQ(fmt::format(loc, "{:L}", 1234.5), "1~234?5");
   EXPECT_EQ(fmt::format(loc, "{:L}", 12000.0), "12~000");
   EXPECT_EQ(fmt::format(loc, "{:8L}", 1230.0), "   1~230");
+  EXPECT_EQ(fmt::format(loc, "{:15.6Lf}", 0.1), "       0?100000");
+  EXPECT_EQ(fmt::format(loc, "{:15.6Lf}", 1.0), "       1?000000");
+  EXPECT_EQ(fmt::format(loc, "{:15.6Lf}", 1e3), "   1~000?000000");
 }
 
 TEST(locale_test, format) {
@@ -441,16 +496,16 @@ TEST(locale_test, wformat) {
             fmt::format(small_grouping_loc, L"{:L}", max_value<uint32_t>()));
 }
 
-TEST(locale_test, double_formatter) {
+TEST(locale_test, int_formatter) {
   auto loc = std::locale(std::locale(), new special_grouping<char>());
   auto f = fmt::formatter<int>();
   auto parse_ctx = fmt::format_parse_context("L");
   f.parse(parse_ctx);
-  char buf[10] = {};
-  fmt::basic_format_context<char*, char> format_ctx(
-      buf, {}, fmt::detail::locale_ref(loc));
-  *f.format(12345, format_ctx) = 0;
-  EXPECT_STREQ("12,345", buf);
+  auto buf = fmt::memory_buffer();
+  fmt::basic_format_context<fmt::appender, char> format_ctx(
+      fmt::appender(buf), {}, fmt::detail::locale_ref(loc));
+  f.format(12345, format_ctx);
+  EXPECT_EQ(fmt::to_string(buf), "12,345");
 }
 
 FMT_BEGIN_NAMESPACE
@@ -461,13 +516,10 @@ template <class charT> struct formatter<std::complex<double>, charT> {
  public:
   FMT_CONSTEXPR typename basic_format_parse_context<charT>::iterator parse(
       basic_format_parse_context<charT>& ctx) {
-    using handler_type =
-        detail::dynamic_specs_handler<basic_format_parse_context<charT>>;
-    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                detail::type::string_type);
-    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
-    detail::parse_float_type_spec(specs_, ctx.error_handler());
-    return it;
+    auto end = parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
+                                  detail::type::float_type);
+    detail::parse_float_type_spec(specs_, detail::error_handler());
+    return end;
   }
 
   template <class FormatContext>
@@ -518,4 +570,12 @@ TEST(locale_test, sign) {
   EXPECT_EQ(fmt::format(std::locale(), L"{:L}", -50), L"-50");
 }
 
+TEST(std_test_xchar, optional) {
+#  ifdef __cpp_lib_optional
+  EXPECT_EQ(fmt::format(L"{}", std::optional{L'C'}), L"optional(\'C\')");
+  EXPECT_EQ(fmt::format(L"{}", std::optional{std::wstring{L"wide string"}}),
+            L"optional(\"wide string\")");
+#  endif
+}
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR