Releases: fmtlib/fmt
5.2.0
-
Optimized format string parsing and argument processing which resulted in up to 5x speed up on long format strings and significant performance boost on various benchmarks. For example, version 5.2 is 2.22x faster than 5.1 on decimal integer formatting with
format_to
(macOS, clang-902.0.39.2):Method Time, s Speedup fmt::format 5.1 0.58 fmt::format 5.2 0.35 1.66x fmt::format_to 5.1 0.51 fmt::format_to 5.2 0.23 2.22x sprintf 0.71 std::to_string 1.01 std::stringstream 1.73 -
Changed the
fmt
macro from opt-out to opt-in to prevent name collisions. To enable it define theFMT_STRING_ALIAS
macro to 1 before includingfmt/format.h
:#define FMT_STRING_ALIAS 1 #include <fmt/format.h> std::string answer = format(fmt("{}"), 42);
-
Added compile-time format string checks to
format_to
overload that takesfmt::memory_buffer
(#783):fmt::memory_buffer buf; // Compile-time error: invalid type specifier. fmt::format_to(buf, fmt("{:d}"), "foo");
-
Moved experimental color support to
fmt/color.h
and enabled the new API by default. The old API can be enabled by defining theFMT_DEPRECATED_COLORS
macro. -
Added formatting support for types explicitly convertible to
fmt::string_view
:struct foo { explicit operator fmt::string_view() const { return "foo"; } }; auto s = format("{}", foo());
In particular, this makes formatting function work with
folly::StringPiece
. -
Implemented preliminary support for
char*_t
by replacing theformat
function overloads with a single function template parameterized on the string type. -
Added support for dynamic argument lists (#814, #819). Thanks @MikePopoloski (Michael Popoloski).
-
Reduced executable size overhead for embedded targets using newlib nano by making locale dependency optional (#839). Thanks @teajay-fr (Thomas Benard).
-
Keep
noexcept
specifier when exceptions are disabled (#801, #810). Thanks @qis (Alexej Harm). -
Fixed formatting of user-defined types providing
operator<<
withformat_to_n
(#806). Thanks @mkurdej (Marek Kurdej). -
Fixed dynamic linkage of new symbols (#808).
-
Fixed global initialization issue (#807):
// This works on compilers with constexpr support. static const std::string answer = fmt::format("{}", 42);
-
Fixed various compiler warnings and errors (#804, #809, #811, #822, #827, #830, #838, #843, #844, #851, #852, #854). Thanks @henryiii (Henry Schreiner), @medithe, and @eliasdaler (Elias Daler).
5.1.0
-
Added experimental support for RGB color output enabled with the
FMT_EXTENDED_COLORS
macro:#define FMT_EXTENDED_COLORS #define FMT_HEADER_ONLY // or compile fmt with FMT_EXTENDED_COLORS defined #include <fmt/format.h> fmt::print(fmt::color::steel_blue, "Some beautiful text");
The old API (the
print_colored
andvprint_colored
functions and thecolor
enum) is now deprecated. (#762 #767). Thanks @Remotion (Remo). -
Added quotes to strings in ranges and tuples (#766). Thanks @Remotion (Remo).
-
Made
format_to
work withbasic_memory_buffer
(#776). -
Added
vformat_to_n
andwchar_t
overload offormat_to_n
(#764, #769). -
Made
is_range
andis_tuple_like
part of public (experimental) API to allow specialization for user-defined types (#751, #759). Thanks @drrlvn (Dror Levin). -
Added more compilers to continuous integration and increased
FMT_PEDANTIC
warning levels (#736). Thanks @eliaskosunen (Elias Kosunen). -
Fixed compilation with MSVC 2013.
-
Fixed handling of user-defined types in
format_to
(#793). -
Forced linking of inline
vformat
functions into the library (#795). -
Fixed incorrect call to on_align in
'{:}='
(#750). -
Fixed floating-point formatting to a non-back_insert_iterator with sign & numeric alignment specified (#756).
-
Fixed formatting to an array with
format_to_n
(#778). -
Fixed formatting of more than 15 named arguments (#754).
-
Fixed handling of compile-time strings when including
fmt/ostream.h
. (#768). -
Fixed various compiler warnings and errors (#742, #748, #752, #770, #775, #779, #780, #790, #792, #800). Thanks @Remotion (Remo), @gabime (Gabi Melman), @foonathan (Jonathan Müller), @Dark-Passenger (Dhruv Paranjape), and @0x8000-0000 (Sign Bit).
5.0.0
-
Added a requirement for partial C++11 support, most importantly variadic templates and type traits, and dropped
FMT_VARIADIC_*
emulation macros. Variadic templates are available since GCC 4.4, Clang 2.9 and MSVC 18.0 (2013). For older compilers use {fmt} version 4.x which continues to be maintained and works with C++98 compilers. -
Renamed symbols to follow standard C++ naming conventions and proposed a subset of the library for standardization in P0645R2 Text Formatting.
-
Implemented
constexpr
parsing of format strings and compile-time format string checks. For example#include <fmt/format.h> std::string s = format(fmt("{:d}"), "foo");
gives a compile-time error because
d
is an invalid specifier for strings (godbolt):... <source>:4:19: note: in instantiation of function template specialization 'fmt::v5::format<S, char [4]>' requested here std::string s = format(fmt("{:d}"), "foo"); ^ format.h:1337:13: note: non-constexpr function 'on_error' cannot be used in a constant expression handler.on_error("invalid type specifier");
Compile-time checks require relaxed
constexpr
(C++14 feature) support. If the latter is not available, checks will be performed at runtime. -
Separated format string parsing and formatting in the extension API to enable compile-time format string processing. For example
struct Answer {}; namespace fmt { template <> struct formatter<Answer> { constexpr auto parse(parse_context& ctx) { auto it = ctx.begin(); spec = *it; if (spec != 'd' && spec != 's') throw format_error("invalid specifier"); return ++it; } template <typename FormatContext> auto format(Answer, FormatContext& ctx) { return spec == 's' ? format_to(ctx.begin(), "{}", "fourty-two") : format_to(ctx.begin(), "{}", 42); } char spec = 0; }; } std::string s = format(fmt("{:x}"), Answer());
gives a compile-time error due to invalid format specifier (godbolt):
... <source>:12:45: error: expression '<throw-expression>' is not a constant expression throw format_error("invalid specifier");
-
Added iterator support:
#include <vector> #include <fmt/format.h> std::vector<char> out; fmt::format_to(std::back_inserter(out), "{}", 42);
-
Added the format_to_n function that restricts the output to the specified number of characters (#298):
char out[4]; fmt::format_to_n(out, sizeof(out), "{}", 12345); // out == "1234" (without terminating '\0')
-
Added the formatted_size function for computing the output size:
#include <fmt/format.h> auto size = fmt::formatted_size("{}", 12345); // size == 5
-
Improved compile times by reducing dependencies on standard headers and providing a lightweight core API:
#include <fmt/core.h> fmt::print("The answer is {}.", 42);
-
Added the make_format_args function for capturing formatting arguments:
// Prints formatted error message. void vreport_error(const char *format, fmt::format_args args) { fmt::print("Error: "); fmt::vprint(format, args); } template <typename... Args> void report_error(const char *format, const Args & ... args) { vreport_error(format, fmt::make_format_args(args...)); }
-
Added the
make_printf_args
function for capturingprintf
arguments ( #687, #694). Thanks @Kronuz (Germán Méndez Bravo). -
Added prefix
v
to non-variadic functions takingformat_args
to distinguish them from variadic ones:std::string vformat(string_view format_str, format_args args); template <typename... Args> std::string format(string_view format_str, const Args & ... args);
-
Added experimental support for formatting ranges, containers and tuple-like types in
fmt/ranges.h
(#735):#include <fmt/ranges.h> std::vector<int> v = {1, 2, 3}; fmt::print("{}", v); // prints {1, 2, 3}
Thanks @Remotion (Remo).
-
Implemented
wchar_t
date and time formatting (#712):#include <fmt/time.h> std::time_t t = std::time(nullptr); auto s = fmt::format(L"The date is {:%Y-%m-%d}.", *std::localtime(&t));
Thanks @DanielaE (Daniela Engert).
-
Provided more wide string overloads (#724). Thanks @DanielaE (Daniela Engert).
-
Switched from a custom null-terminated string view class to
string_view
in the format API and providedfmt::string_view
which implements a subset ofstd::string_view
API for pre-C++17 systems. -
Added support for
std::experimental::string_view
(#607):#include <fmt/core.h> #include <experimental/string_view> fmt::print("{}", std::experimental::string_view("foo"));
-
Allowed mixing named and automatic arguments:
fmt::format("{} {two}", 1, fmt::arg("two", 2));
-
Removed the write API in favor of the format API with compile-time handling of format strings.
-
Disallowed formatting of multibyte strings into a wide character target (#606).
-
Improved documentation ( #515, #614, #617, #661, #680). Thanks @ibell (Ian Bell), @mihaitodor (Mihai Todor), and @johnthagen.
-
Implemented more efficient handling of large number of format arguments.
-
Introduced an inline namespace for symbol versioning.
-
Added debug postfix
d
to thefmt
library name (#636). -
Removed unnecessary
fmt/
prefix in includes (#397). Thanks @chronoxor (Ivan Shynkarenka). -
Moved
fmt/*.h
toinclude/fmt/*.h
to prevent irrelevant files and directories appearing on the include search paths when fmt is used as a subproject and moved source files to thesrc
directory. -
Added qmake project file
support/fmt.pro
(#641). Thanks @cowo78 (Giuseppe Corbelli). -
Added Gradle build file
support/build.gradle
(#649). Thanks @luncliff (Park DongHa). -
Removed
FMT_CPPFORMAT
CMake option. -
Fixed a name conflict with the macro
CHAR_WIDTH
in glibc (#616). Thanks @aroig (Abdó Roig-Maranges). -
Fixed handling of nested braces in
fmt::join
(#638). -
Added
SOURCELINK_SUFFIX
for compatibility with Sphinx 1.5 (#497). Thanks @ginggs (Graham Inggs). -
Added a missing
inline
in the header-only mode (#626). Thanks @aroig (Abdó Roig-Maranges). -
Fixed various compiler warnings ( #640, #656, #679, #681, #705, #715, #717, #720, #723, #726, #730, #739). Thanks @peterbell10, @LarsGullik, @foonathan (Jonathan Müller), @eliaskosunen (Elias Kosunen), @christianparpart (Christian Parpart), @DanielaE (Daniela Engert), and @mwinterb.
-
Worked around an MSVC bug and fixed several warnings (#653). Thanks @alabuzhev (Alex Alabuzhev).
-
Worked around GCC bug 67371 (#682).
-
Fixed compilation with
-fno-exceptions
(#655). Thanks @chenxiaolong (Andrew Gunnerson). -
Made
constexpr remove_prefix
gcc version check tighter (#648). -
Renamed internal type enum constants to prevent collision with poorly written C libraries (#644).
-
Added detection of
wostream operator<<
(#650). -
Fixed compilation when there is a mismatch between
-std
options between the library and user code (#664). -
Fixed compilation with GCC 7 and
-std=c++11
(#734). -
Improved generated binary code on GCC 7 and older (#668).
-
Fixed handling of numeric alignment with no width (#675).
-
Fixed handling of empty strings in UTF8/16 converters (#676). Thanks @vgalka-sl (Vasili Galka).
-
Fixed formatting of an empty
string_view
(#689). -
Fixed detection of
string_view
on libc++ (#686). -
Fixed DLL issues (#696). Thanks @sebkoenig.
-
Fixed compile checks for mixing narrow and wide strings (#690).
-
Disabled unsafe implicit conversion to
std::string
(#729). -
Fixed handling of reused format specs (as in
fmt::join
) for pointers (#725). Thanks @mwinterb. -
Fixed installation of
fmt/ranges.h
(#738). Thanks @sv1990....
4.1.0
-
Added
fmt::to_wstring()
in addition tofmt::to_string()
(#559). Thanks @alabuzhev (Alex Alabuzhev). -
Added support for C++17
std::string_view
(#571 and #578). Thanks @thelostt (Mário Feroldi) and @mwinterb. -
Enabled stream exceptions to catch errors (#581). Thanks @crusader-mike.
-
Allowed formatting of class hierarchies with
fmt::format_arg()
(#547). Thanks @rollbear (Björn Fahller). -
Removed limitations on character types (#563). Thanks @Yelnats321 (Elnar Dakeshov).
-
Conditionally enabled use of
std::allocator_traits
(#583). Thanks @mwinterb. -
Added support for
const
variadic member function emulation withFMT_VARIADIC_CONST
(#591). Thanks @ludekvodicka (Ludek Vodicka). -
Various bugfixes: bad overflow check, unsupported implicit type conversion when determining formatting function, test segfaults (#551), ill-formed macros (#542) and ambiguous overloads (#580). Thanks @xylosper (Byoung-young Lee).
-
Prevented warnings on MSVC (#605, #602, and #545), clang (#582), GCC (#573), various conversion warnings (#609, #567, #553 and #553), and added
override
and[[noreturn]]
(#549 and #555). Thanks @alabuzhev (Alex Alabuzhev), @virgiliofornazin (Virgilio Alexandre Fornazin), @alexanderbock (Alexander Bock), @yumetodo, @VaderY (Császár Mátyás), @jpcima (JP Cimalando), @thelostt (Mário Feroldi), and @Manu343726 (Manu Sánchez). -
Improved CMake: Used GNUInstallDirs to set installation location (#610) and fixed warnings (#536 and #556). Thanks @mikecrowe (Mike Crowe), @evgen231 and @henryiii (Henry Schreiner).
4.0.0
-
Removed old compatibility headers
cppformat/*.h
and CMake options (#527). Thanks @maddinat0r (Alex Martin). -
Added
string.h
containingfmt::to_string()
as alternative tostd::to_string()
as well as other string writer functionality (#326 and #441):#include "fmt/string.h" std::string answer = fmt::to_string(42);
Thanks to @glebov-andrey (Andrey Glebov).
-
Moved
fmt::printf()
to newprintf.h
header and allowed%s
as generic specifier (#453), made%.f
more conformant to regularprintf()
(#490), added custom writer support (#476) and implemented missing custom argument formatting (#339 and #340):#include "fmt/printf.h" // %s format specifier can be used with any argument type. fmt::printf("%s", 42);
Thanks @mojoBrendan, @manylegged (Arthur Danskin) and @spacemoose (Glen Stark). See also #360, #335 and #331.
-
Added
container.h
containing aBasicContainerWriter
to write to containers likestd::vector
(#450). Thanks @polyvertex (Jean-Charles Lefebvre). -
Added
fmt::join()
function that takes a range and formats its elements separated by a given string (#466):#include "fmt/format.h" std::vector<double> v = {1.2, 3.4, 5.6}; // Prints "(+01.20, +03.40, +05.60)". fmt::print("({:+06.2f})", fmt::join(v.begin(), v.end(), ", "));
Thanks @olivier80.
-
Added support for custom formatting specifications to simplify customization of built-in formatting (#444). Thanks @polyvertex (Jean-Charles Lefebvre). See also #439.
-
Added
fmt::format_system_error()
for error code formatting (#323 and #526). Thanks @maddinat0r (Alex Martin). -
Added thread-safe
fmt::localtime()
andfmt::gmtime()
as replacement for the standard version totime.h
(#396). Thanks @codicodi. -
Internal improvements to
NamedArg
andArgLists
(#389 and #390). Thanks @chronoxor. -
Fixed crash due to bug in
FormatBuf
(#493). Thanks @effzeh. See also #480 and #491. -
Fixed handling of wide strings in
fmt::StringWriter
. -
Improved compiler error messages (#357).
-
Fixed various warnings and issues with various compilers (#494, #499, #483, #519, #485, #482, #475, #473 and #414). Thanks @chronoxor, @zhaohuaxishi, @pkestene (Pierre Kestener), @dschmidt (Dominik Schmidt) and @0x414c (Alexey Gorishny) .
-
Improved CMake: targets are now namespaced (#511 and #513), supported header-only
printf.h
(#354), fixed issue with minimal supported library subset (#418, #419 and #420). Thanks @bjoernthiel (Bjoern Thiel), @niosHD (Mario Werner), @LogicalKnight (Sean LK) and @alabuzhev (Alex Alabuzhev). -
Improved documentation. Thanks to @pwm1234 (Phil) for #393.
3.0.2
-
Added
FMT_VERSION
macro (#411). -
Used
FMT_NULL
instead of literal0
(#409). Thanks @alabuzhev (Alex Alabuzhev). -
Added extern templates for
format_float
(#413). -
Fixed implicit conversion issue (#507).
-
Fixed signbit detection (#423).
-
Fixed naming collision (#425).
-
Fixed missing intrinsic for C++/CLI (#457). Thanks @calumr (Calum Robinson)
-
Fixed Android detection (#458). Thanks @Gachapen (Magnus Bjerke Vik).
-
Use lean
windows.h
if not in header-only mode (#503). Thanks @Quentin01 (Quentin Buathier). -
Fixed issue with CMake exporting C++11 flag (#445). Thanks @EricWF (Eric).
-
Fixed issue with nvcc and MSVC compiler bug and MinGW (#505).
-
Fixed DLL issues (#469 and #502). Thanks @richardeakin (Richard Eakin) and @AndreasSchoenle (Andreas Schönle).
-
Fixed test compilation under FreeBSD (#433).
-
Fixed various warnings (#403, #410 and #510). Thanks @Lecetem, @chenhayat (Chen Hayat) and @trozen.
-
Removed redundant include (#479).
-
Fixed documentation issues.
3.0.1
- Fixed handling of thousands seperator (#353)
- Fixed handling of
unsigned char
strings (#373) - Corrected buffer growth when formatting time (#367)
- Removed warnings under MSVC and clang (#318, #250, also merged #385 and #361). Thanks @jcelerier (Jean-Michaël Celerier) and @nmoehrle (Nils Moehrle).
- Fixed compilation issues under Android (#327, #345 and #381), FreeBSD (#358), Cygwin (#388), MinGW (#355) as well as other issues (#350, #366, #348, #402, #405). Thanks to @dpantele (Dmitry), @hghwng (Hugh Wang), @arvedarved (Tilman Keskinöz), @LogicalKnight (Sean) and @JanHellwig (Jan Hellwig).
- Fixed some documentation issues and extended specification (#320, #333, #347, #362). Thanks to @smellman (Taro Matsuzawa aka. btm).
3.0.0
-
The project has been renamed from C++ Format (cppformat) to fmt for consistency with the used namespace and macro prefix (#307). Library headers are now located in the
fmt
directory:#include "fmt/format.h"
Including
format.h
from thecppformat
directory is deprecated but works via a proxy header which will be removed in the next major version.The documentation is now available at http://fmtlib.net. -
Added support for strftime-like date and time formatting (#283):
#include "fmt/time.h" std::time_t t = std::time(nullptr); // Prints "The date is 2016-04-29." (with the current date) fmt::print("The date is {:%Y-%m-%d}.", *std::localtime(&t));
-
std::ostream
support including formatting of user-defined types that provide overloadedoperator<<
has been moved tofmt/ostream.h
:#include "fmt/ostream.h" class Date { int year_, month_, day_; public: Date(int year, int month, int day) : year_(year), month_(month), day_(day) {} friend std::ostream &operator<<(std::ostream &os, const Date &d) { return os << d.year_ << '-' << d.month_ << '-' << d.day_; } }; std::string s = fmt::format("The date is {}", Date(2012, 12, 9)); // s == "The date is 2012-12-9"
-
Added support for custom argument formatters (#235).
-
Added support for locale-specific integer formatting with the
n
specifier (#305):std::setlocale(LC_ALL, "en_US.utf8"); fmt::print("cppformat: {:n}\n", 1234567); // prints 1,234,567
-
Sign is now preserved when formatting an integer with an incorrect
printf
format specifier (#265):fmt::printf("%lld", -42); // prints -42
Note that it would be an undefined behavior in
std::printf
. -
Length modifiers such as
ll
are now optional in printf formatting functions and the correct type is determined automatically (#255):fmt::printf("%d", std::numeric_limits<long long>::max());
Note that it would be an undefined behavior in
std::printf
. -
Added initial support for custom formatters (#231).
-
Fixed detection of user-defined literal support on Intel C++ compiler (#311, #312). Thanks to @dean0x7d (Dean Moldovan) and @speth (Ray Speth).
-
Reduced compile time (#243, #249, #317):
Thanks to @dean0x7d (Dean Moldovan).
-
Compile test fixes (#313). Thanks to @dean0x7d (Dean Moldovan).
-
Documentation fixes (#239, #248, #252, #258, #260, #301, #309). Thanks to @ReadmeCritic @Gachapen (Magnus Bjerke Vik) and @jwilk (Jakub Wilk).
-
Fixed compiler and sanitizer warnings (#244, #256, #259, #263, #274, #277, #286, #291, #296, #308) Thanks to @mwinterb, @pweiskircher (Patrik Weiskircher), @Naios.
-
Improved compatibility with Windows Store apps (#280, #285) Thanks to @mwinterb.
-
Added tests of compatibility with older C++ standards (#273). Thanks to @niosHD.
-
Changed
ArgMap
to be backed by a vector instead of a map. (#261, #262). Thanks to @mwinterb. -
Added
fprintf
overload that writes to astd::ostream
(#251). Thanks to nickhutchinson (Nicholas Hutchinson). -
Export symbols when building a Windows DLL (#245). Thanks to macdems (Maciek Dems).
-
Fixed compilation on Cygwin (#304).
-
Implemented a workaround for a bug in Apple LLVM version 4.2 of clang (#276).
-
Implemented a workaround for Google Test bug #705 on gcc 6 (#268). Thanks to octoploid.
-
Removed Biicode support because the latter has been discontinued.
2.1.1
2.1.0
-
Project layout and build system improvements (#267):
- The code have been moved to the
cppformat
directory. Includingformat.h
from the top-level directory is deprecated but works via a proxy header which will be removed in the next major version. - C++ Format CMake targets now have proper interface definitions.
- Installed version of the library now supports the header-only configuration.
- Targets
doc
,install
, andtest
are now disabled if C++ Format is included as a CMake subproject. They can be enabled by settingFMT_DOC
,FMT_INSTALL
, andFMT_TEST
in the parent project.
Thanks to @niosHD.
- The code have been moved to the