-   Added support for the `%j` specifier (the number of days) for `std::chrono::duration` (https://github.com/fmtlib/fmt/issues/3643, https://github.com/fmtlib/fmt/pull/3732). Thanks @intelfx.


Added support for the chrono suffix for days and changed the suffix for minutes from "m" to the correct "min" (Formatting durations fmtlib/fmt#3662, suffixes for helper chrono types added in C++  20 fmtlib/fmt#3664). For example (godbolt):
#include <fmt/chrono.h>

int main() {
  fmt::print("{}\n", std::chrono::days(42)); // prints "42d"
}
Thanks @Richardk2n.


Fixed an overflow in std::chrono::time_point formatting with large dates (Date overflow with std::chrono::time_point fmtlib/fmt#3725, Fix overflow in time_point formatting with large dates fmtlib/fmt#3727). Thanks @cschreib.


Added a formatter for std::source_location (Added formatter for std::source_location fmtlib/fmt#3730). For example (godbolt):
#include <source_location>
#include <fmt/std.h>

int main() {
  fmt::print("{}\n", std::source_location::current());
}
prints
/app/example.cpp:5:51: int main()

Thanks @felix642.


Added a formatter for std::bitset (fix: make std::bitset formattable again fmtlib/fmt#3660). For example (godbolt):
#include <bitset>
#include <fmt/std.h>

int main() {
  fmt::print("{}\n", std::bitset<6>(42)); // prints "101010"
}
Thanks @muggenhor.


Added an experimental nested_formatter that provides an easy way of applying a formatter to one or more subobjects while automatically handling width, fill and alignment. For example:
#include <fmt/format.h>

struct point {
  double x, y;
};

template <>
struct fmt::formatter<point> : nested_formatter<double> {
  auto format(point p, format_context& ctx) const {
    return write_padded(ctx, [=](auto out) {
      return format_to(out, "({}, {})", nested(p.x), nested(p.y));
    });
  }
};

int main() {
  fmt::print("[{:>20.2f}]", point{1, 2});
}
prints
[          (1.00, 2.00)]



Added the generic representation (g) to std::filesystem::path (Support both generic and native format of std::filesystem::path fmtlib/fmt#3715, Add native and generic representation for filesystem::path format spec fmtlib/fmt#3729). For example:
#include <filesystem>
#include <fmt/std.h>

int main() {
  fmt::print("{:g}\n", std::filesystem::path("C:\\foo"));
}
prints "C:/foo" on Windows.
Thanks @js324.


Made format_as work with references (allow format_as() to format reference fmtlib/fmt#3739). Thanks @tchaikov.


Fixed formatting of invalid UTF-8 with precision (Extra characters printed when formatting invalid UTF-8 with precision fmtlib/fmt#3284).


Fixed an inconsistency between fmt::to_string and fmt::format (Inconsistency between fmt::to_string(_) and fmt::format("{}", _) fmtlib/fmt#3684).


Disallowed unsafe uses of fmt::styled (Cannot decide between different fmt::styles at runtime, gives crashes. fmtlib/fmt#3625):
auto s = fmt::styled(std::string("dangle"), fmt::emphasis::bold);
fmt::print("{}\n", s); // compile error
Pass fmt::styled(...) as a parameter instead.


Added a null check when formatting a C string with the s specifier (Crash formatting null strings fmtlib/fmt#3706).


Disallowed the c specifier for bool (presentation_type c accepted in combination with bool fmtlib/fmt#3726, Disallow presentation_type c in combination with bool arg  fmtlib/fmt#3734). Thanks @js324.


Made the default formatting unlocalized in fmt::ostream_formatter for consistency with the rest of the library (Question: locale treated differently by fmt and std::cout fmtlib/fmt#3460).


Fixed localized formatting in bases other than decimal (Localized formatting is always decimal fmtlib/fmt#3693, Add localized formatting to non-decimal presentation types of ints fmtlib/fmt#3750). Thanks @js324.


Fixed a performance regression in experimental fmt::ostream::print (Performance regression since 10.0.0 fmtlib/fmt#3674).


Added synchronization with the underlying output stream when writing to the Windows console (Added synchronization with the main storage device before direct recording fmtlib/fmt#3668, Incorrect call to fflush() inside write_console() fmtlib/fmt#3688, Fix flushing C++ iostreams before calling write_console() fmtlib/fmt#3689). Thanks @Roman-Koshelev and @dimztimz.


Changed to only export format_error when {fmt} is built as a shared library (Reconsider forcibly exporting format_error symbol on GCC fmtlib/fmt#3626, Fix symbol leak fmtlib/fmt#3627). Thanks @phprus.


Made fmt::streamed constexpr. (fix: mark fmt::streamed() as constexpr fmtlib/fmt#3650). Thanks @muggenhor.


Enabled consteval on older versions of MSVC (Enable consteval in MSVC VS2019 version 16.10 fmtlib/fmt#3757). Thanks @phprus.


Added an option to build without wchar_t support on Windows (Windows API systems without UTF-16 APIs fmtlib/fmt#3631, Add an option to avoid wchar APIs on Windows fmtlib/fmt#3636). Thanks @glebm.


Improved build and CI configuration (Add support for CMake 3.28 C++ module features fmtlib/fmt#3679, CMake does not set PDB path for Visual Studio fmtlib/fmt#3701, Set PDB path for Visual Studio fmtlib/fmt#3702, CI: add lint github workflow for running clang-format fmtlib/fmt#3749). Thanks @jcar87, @pklima and @tchaikov.


Fixed various warnings, compilation and test issues (Clang 18 rejects operator"" _a fmtlib/fmt#3607, Avoid a space in the UDL definition fmtlib/fmt#3610, Remove type cast as mxe(mingw32) compiler complains about useless-cast fmtlib/fmt#3624, fix redundant redeclaration of ‘constexpr’ static data member fmtlib/fmt#3630, Fix deprecation warning in libc++ (LLVM-16) fmtlib/fmt#3634, Replace use of newer C++ library feature with older equivalent fmtlib/fmt#3638, Unexpected output from intel fmt::fprint fmtlib/fmt#3645, signed/unsigned error on MSVC 14.36.32532 fmtlib/fmt#3646, Fix datatype of underlying data to avoid signed/unsigned compiler warning with MSVC fmtlib/fmt#3647, Workaround intel bug fmtlib/fmt#3652, Compilation fails using Clang 17 toolchain fmtlib/fmt#3654, Remove leftover usage of the __std_stream header fmtlib/fmt#3663, 4 test failures on OpenBSD x86_64 (chrono-test, gtest-extra-test, xchar-test, posix-mock-test) fmtlib/fmt#3670, Fix error C2668 on Windows with option /std:c++latest fmtlib/fmt#3680, High impact Coverity finding in include/fmt/format.h fmtlib/fmt#3694, Wrap Char in array to avoid pointer arithmetic fmtlib/fmt#3695, Fix include xlocale fmtlib/fmt#3699, <fmt/std.h> compilation failure with MinGW fmtlib/fmt#3705, fmt::format doesn't seem to work with bidirectional nested ranges fmtlib/fmt#3710, formatting a std::optional with format_as function fails to compile using clang fmtlib/fmt#3712, fix: support optional<T> with format_as(T) (#3712) fmtlib/fmt#3713, Fresh update of CMakeLists.txt incorrect? fmtlib/fmt#3714, Added workaround for old xcode compiler bug fmtlib/fmt#3716, Remove this-> from decltype fmtlib/fmt#3723, Compile error with GCC 6.3.0 fmtlib/fmt#3738, Compilation error with clang in CUDA mode fmtlib/fmt#3740, Fix CMake build fmtlib/fmt#3741, Fix compile with GCC 6.3.0 (bug #3738) fmtlib/fmt#3743, isfinite declared constexpr for c++20 fmtlib/fmt#3745, Fix typo in gmock-gtest-all.cc fmtlib/fmt#3747, Fix warning: identifier '_a' preceded by whitespace in a literal operator declaration is deprecated fmtlib/fmt#3748, Use void(*)(void*) instead of decltype(&std::free) to satisfy clang in CUDA mode fmtlib/fmt#3751, Add stdlib version check for C++20 fmtlib/fmt#3754, Apply clang-format fmtlib/fmt#3755, format_test.format_double fails fmtlib/fmt#3760, Make hex float test more stable on different libc fmtlib/fmt#3762, format_as converting struct to tuple no longer works fmtlib/fmt#3763, Fix wchar_t to char conversion warnings fmtlib/fmt#3764, chrono-test failing on i386 and armhf on Ubuntu fmtlib/fmt#3774, Consistently use fmt:: when invoking format_to. fmtlib/fmt#3779). Thanks @danakj, @vinayyadav3016, @cyyever, @phprus, @qimiko, @saschasc, @gsjaardema, @lazka, @Zhaojun-Liu, @carlsmedstad, @hotwatermorning, @cptFracassa, @kuguma, @PeterJohnson, @H1X4Dev, @asantoni, @eltociear, @msimberg, @tchaikov, @waywardmonkeys.


Improved documentation and README (Improve documentation for best practices around specializing fmt::formatter fmtlib/fmt#2086, fmt::print() throwing on file IO errors should at least be clearly documented fmtlib/fmt#3637, Remove unnecessary spaces fmtlib/fmt#3642, README.rst: fix broken LICENSE link fmtlib/fmt#3653, Add security policy to readme fmtlib/fmt#3655, minor fix to README.rst security policy link fmtlib/fmt#3661, ? format spec is undocumented fmtlib/fmt#3673, add meson instructions to usage docs fmtlib/fmt#3677, Update README.rst fmtlib/fmt#3737, Reference to README.rst broken in CMakeLists.txt fmtlib/fmt#3742, Fix README file table fmtlib/fmt#3744). Thanks @idzm, @perlun, @joycebrum, @fennewald, @reinhardt1053, @GeorgeLS.


Updated CI dependencies (Bump actions/checkout from 3.5.3 to 3.6.0 fmtlib/fmt#3615, Bump github/codeql-action from 2.21.4 to 2.21.5 fmtlib/fmt#3622, Bump actions/checkout from 3.5.3 to 4.0.0 fmtlib/fmt#3623, Bump actions/checkout from 4.0.0 to 4.1.0 fmtlib/fmt#3666, Bump github/codeql-action from 2.21.5 to 2.22.5 fmtlib/fmt#3696, Bump ossf/scorecard-action from 2.2.0 to 2.3.1 fmtlib/fmt#3697, [StepSecurity] ci: Harden GitHub Actions fmtlib/fmt#3759, Bump actions/upload-artifact from 3.1.2 to 4.0.0 fmtlib/fmt#3782).