0e4e4b37d9
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.
113 lines
2.9 KiB
C++
113 lines
2.9 KiB
C++
// -*- C++ -*- forwarding header.
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// Copyright (C) 2015-2022 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/cuchar
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* This is a Standard C++ Library file. You should @c #include this file
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* in your programs, rather than any of the @a *.h implementation files.
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*
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* This is the C++ version of the Standard C Library header @c uchar.h,
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* and its contents are (mostly) the same as that header, but are all
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* contained in the namespace @c std (except for names which are defined
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* as macros in C).
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*/
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//
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// ISO C++ 14882:2011 21.8
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//
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#ifndef _GLIBCXX_CUCHAR
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#define _GLIBCXX_CUCHAR 1
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#pragma GCC system_header
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#if __cplusplus < 201103L
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# include <bits/c++0x_warning.h>
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#else
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#include <bits/c++config.h>
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#include <cwchar>
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#if _GLIBCXX_USE_C11_UCHAR_CXX11
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#if (_GLIBCXX_USE_C11_UCHAR_CXX11 \
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|| (_GLIBCXX_USE_CHAR8_T \
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&& (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
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|| (__cplusplus >= 202002 \
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&& _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20))))
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#include <uchar.h>
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#endif
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// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library.
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#if (_GLIBCXX_USE_CHAR8_T \
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&& (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
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|| (__cplusplus >= 202002 \
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&& _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20)))
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// Get rid of those macros defined in <uchar.h> in lieu of real functions.
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#undef mbrtoc8
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#undef c8rtomb
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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using ::mbrtoc8;
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using ::c8rtomb;
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif // _GLIBCXX_USE_CHAR8_T
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#if _GLIBCXX_USE_C11_UCHAR_CXX11
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// Get rid of those macros defined in <uchar.h> in lieu of real functions.
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#undef mbrtoc16
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#undef c16rtomb
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#undef mbrtoc32
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#undef c32rtomb
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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using ::mbrtoc16;
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using ::c16rtomb;
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using ::mbrtoc32;
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using ::c32rtomb;
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif // _GLIBCXX_USE_C11_UCHAR_CXX11
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#endif // C++11
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#endif // _GLIBCXX_CUCHAR
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