Tom Honermann 0e4e4b37d9 libstdc++: Declare std::c8rtomb and std::mbrtoc8 if provided by the C library ... This patch completes implementation of the C++20 proposal P0482R6 [1] by adding declarations of std::c8rtomb() and std::mbrtoc8() in <cuchar> if provided by the C library in <uchar.h>. This patch addresses feedback provided in response to a previous patch submission [2]. Autoconf changes determine if the C library declares c8rtomb and mbrtoc8 at global scope when uchar.h is included and compiled with either -fchar8_t or -std=c++20. New _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros reflect the probe results. The <cuchar> header declares these functions in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T configuration macro is defined (by default it is defined if the C++20 __cpp_char8_t feature test macro is defined) Patches to glibc to implement c8rtomb and mbrtoc8 have been submitted [3]. New tests validate the presence of these declarations. The tests pass trivially if the C library does not provide these functions. Otherwise they ensure that the functions are declared when <cuchar> is included and either -fchar8_t or -std=c++20 is enabled. 1]: WG21 P0482R6 "char8_t: A type for UTF-8 characters and strings (Revision 6)" https://wg21.link/p0482r6 [2]: [PATCH] C++ P0482R6 char8_t: declare std::c8rtomb and std::mbrtoc8 if provided by the C library https://gcc.gnu.org/pipermail/libstdc++/2021-June/052685.html [3]: "C++20 P0482R6 and C2X N2653" [Patch 0/3]: https://sourceware.org/pipermail/libc-alpha/2022-January/135061.html [Patch 1/3]: https://sourceware.org/pipermail/libc-alpha/2022-January/135062.html [Patch 2/3]: https://sourceware.org/pipermail/libc-alpha/2022-January/135063.html [Patch 3/3]: https://sourceware.org/pipermail/libc-alpha/2022-January/135064.html libstdc++-v3/ChangeLog: * acinclude.m4: Define config macros if uchar.h provides c8rtomb() and mbrtoc8(). * config.h.in: Regenerate. * configure: Regenerate. * include/c_compatibility/uchar.h (c8rtomb, mbrtoc8): Define. * include/c_global/cuchar (c8rtomb, mbrtoc8): Likewise. * include/c_std/cuchar (c8rtomb, mbrtoc8): Likewise. * testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc: New test. * testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc: New test.		2022-01-18 16:31:02 +00:00
..
assert.h
complex.h
ctype.h
errno.h
fenv.h
float.h
inttypes.h
iso646.h
limits.h
locale.h
math.h
setjmp.h
signal.h
stdarg.h
stdatomic.h
stdbool.h
stddef.h
stdint.h
stdio.h
stdlib.h
string.h
tgmath.h
time.h
uchar.h	libstdc++: Declare std::c8rtomb and std::mbrtoc8 if provided by the C library	2022-01-18 16:31:02 +00:00
wchar.h
wctype.h