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| author | Tom Honermann <tom@honermann.net> | 2022-01-17 14:56:33 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2022-01-18 16:31:02 +0000 |
| commit | 0e4e4b37d9944430d0553c283a41e9a29482ccee (patch) | |
| tree | 672c48d4e073a81aa1d536d6661b3855c2f0bae4 /libstdc++-v3/config.h.in | |
| parent | d7f2a09e98520c4e4927f460ad96803b05a205b1 (diff) | |
| download | gcc-0e4e4b37d9944430d0553c283a41e9a29482ccee.zip gcc-0e4e4b37d9944430d0553c283a41e9a29482ccee.tar.gz gcc-0e4e4b37d9944430d0553c283a41e9a29482ccee.tar.bz2 | |
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.
Diffstat (limited to 'libstdc++-v3/config.h.in')
| -rw-r--r-- | libstdc++-v3/config.h.in | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in index 168961a..235d256 100644 --- a/libstdc++-v3/config.h.in +++ b/libstdc++-v3/config.h.in @@ -1010,6 +1010,14 @@ /* Define if obsolescent tmpnam is available in <stdio.h>. */ #undef _GLIBCXX_USE_TMPNAM +/* Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be imported + into namespace std in <cuchar> for C++20. */ +#undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 + +/* Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be imported + into namespace std in <cuchar> for -fchar8_t. */ +#undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T + /* Define if utime is available in <utime.h>. */ #undef _GLIBCXX_USE_UTIME |