gcc 13 issues the following diagnostic for the uchar.h header when the
-Wc++20-compat option is enabled in C++ modes that do not enable char8_t
as a builtin type (C++17 and earlier by default; subject to _GNU_SOURCE
and the gcc -f[no-]char8_t option).
warning: identifier ‘char8_t’ is a keyword in C++20 [-Wc++20-compat]
This change modifies the uchar.h header to suppress the diagnostic through
the use of '#pragma GCC diagnostic' directives for gcc 10 and later (the
-Wc++20-compat option was added in gcc version 10). Unfortunately, a bug
in gcc currently prevents those directives from having the intended effect
as reported at https://gcc.gnu.org/PR106423. A patch for that issue has
been submitted and is available in the email thread archive linked below.
https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598736.html
This change provides implementations for the mbrtoc8 and c8rtomb
functions adopted for C++20 via WG21 P0482R6 and for C2X via WG14
N2653. It also provides the char8_t typedef from WG14 N2653.
The mbrtoc8 and c8rtomb functions are declared in uchar.h in C2X
mode or when the _GNU_SOURCE macro or C++20 __cpp_char8_t feature
test macro is defined.
The char8_t typedef is declared in uchar.h in C2X mode or when the
_GNU_SOURCE macro is defined and the C++20 __cpp_char8_t feature
test macro is not defined (if __cpp_char8_t is defined, then char8_t
is a builtin type).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
As noted in bug 17979 (and as I noted earlier in
<https://sourceware.org/ml/libc-alpha/2012-02/msg00647.html>), uchar.h
has gratuitously complicated code to determine the types for char16_t
and char32_t, and to reject including that header for pre-C11
compilers not defining __CHAR16_TYPE__ and __CHAR32_TYPE__. Since
those types are always required to match uint_least16_t and
uint_least32_t, which glibc knows how to define without reference to
such predefined macros, it's safe just to define those types the same
as the *least* types are defined in stdint.h, so allowing the header
to work with (for example) GCC 4.3.
This patch implements that. bits/types.h is made to define
__int_leastN_t and __uint_leastN_t so the logic for those types can
stay in a single place, and stdint.h is made to use those __*_t to
define the public *_t types. uchar.h is then made to use
__uint_least16_t and __uint_least32_t to define char16_t and char32_t,
so simplifying the logic there. A new test is added that verifies the
types chosen for char16_t and char32_t do indeed match the types the
compiler uses for u"" and U"" string literals.
Tested for x86_64. (I have not tested with any of the older compilers
for which this would actually make a difference to whether you can
include uchar.h.)
[BZ #17979]
* posix/bits/types.h (__int_least8_t): New typedef.
(__uint_least8_t): Likewise.
(__int_least16_t): Likewise.
(__uint_least16_t): Likewise.
(__int_least32_t): Likewise.
(__uint_least32_t): Likewise.
(__int_least64_t): Likewise.
(__uint_least64_t): Likewise.
* sysdeps/generic/stdint.h (int_least8_t): Define using
__int_least8_t.
(int_least16_t): Define using __int_least16_t.
(int_least32_t): Define using __int_least32_t.
(int_least64_t): Define using __int_least64_t.
(uint_least8_t): Define using __uint_least8_t.
(uint_least16_t): Define using __uint_least16_t.
(uint_least32_t): Define using __uint_least32_t.
(uint_least64_t): Define using __uint_least64_t.
* wcsmbs/uchar.h: Include <bits/types.h>.
(char16_t): Define using __uint_least16_t conditional only on
[!__USE_ISOCXX11].
(char32_t): Define using __uint_least32_t conditional only on
[!__USE_ISOCXX11].
* wcsmbs/test-char-types.c: New file.
* wcsmbs/Makefile (tests): Add test-char-types.
wint_t is a little finicky because it might be defined by stddef.h, which
belongs to the compiler.
In addition to the _types_, a bunch of other declarations shared between
wctype.h and wchar.h are factored out to their own header.
* libio/bits/types/FILE.h, libio/bits/types/__FILE.h
* wcsmbs/bits/types/mbstate_t.h, wcsmbs/bits/types/__mbstate_t.h
* wcsmbs/bits/types/wint_t.h: New single-type definition files.
* wctype/bits/wctype-wchar.h: New file holding declarations shared
between wctype.h and wchar.h.
* libio/Makefile, wcsmbs/Makefile, wctype/Makefile:
Install them.
* include/bits/types/FILE.h, include/bits/types/__FILE.h
* include/bits/types/mbstate_t.h, include/bits/types/__mbstate_t.h
* include/bits/types/wint_t.h, include/bits/wcsmbs-wchar.h:
New wrappers.
* include/stdio.h, include/wchar.h, include/wctype.h:
No need to handle __need macros.
* grp/grp.h, gshadow/gshadow.h, hurd/hurd.h, iconv/gconv.h
* libio/stdio.h, mach/mach.h, misc/mntent.h, pwd/pwd.h
* shadow/shadow.h, stdio-common/printf.h, wcsmbs/uchar.h
* wcsmbs/wchar.h, wctype/wctype.h
* sysdeps/generic/_G_config.h, sysdeps/unix/sysv/linux/_G_config.h
Use the new files instead of __need macros.
glibc headers include some code (not particularly consistent or
systematic) to put various declarations in C++ namespaces std and
__c99, if _GLIBCPP_USE_NAMESPACES is defined.
As noted in <https://gcc.gnu.org/ml/libstdc++/2017-03/msg00025.html>,
this macro was removed from libstdc++ in 2000. I don't expect
compilation with such old versions of libstdc++ to work with current
glibc headers anyway (whereas old *binaries* are expected to stay
working with current glibc); this patch (which should be a no-op with
any libstdc++ version postdating that removal) removes all this code
from the glibc headers.
The begin-end-check.pl test, whose comments say it is about checking
these namespace macro calls, is also removed. The code in that test
would have covered __BEGIN_DECLS / __END_DECLS as well, but if those
weren't properly matched it would show up with the
check-installed-headers-cxx tests, so I don't think there is an actual
use for keeping begin-end-check.pl with the namespace code removed.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* misc/sys/cdefs.h (__BEGIN_NAMESPACE_STD): Remove macro.
(__END_NAMESPACE_STD): Likewise.
(__USING_NAMESPACE_STD): Likewise.
(__BEGIN_NAMESPACE_C99): Likewise.
(__END_NAMESPACE_C99): Likewise.
(__USING_NAMESPACE_C99): Likewise.
* math/math.h (_Mdouble_BEGIN_NAMESPACE): Do not define and
undefine macro.
(_Mdouble_END_NAMESPACE): Likewise.
* ctype/ctype.h: Do not handle C++ namespaces.
* libio/bits/stdio-ldbl.h: Likewise.
* libio/stdio.h: Likewise.
* locale/locale.h: Likewise.
* math/bits/mathcalls.h: Likewise.
* setjmp/setjmp.h: Likewise.
* signal/signal.h: Likewise.
* stdlib/bits/stdlib-float.h: Likewise.
* stdlib/bits/stdlib-ldbl.h: Likewise.
* stdlib/stdlib.h: Likewise.
* string/string.h: Likewise.
* sysdeps/x86/fpu/bits/mathinline.h: Likewise.
* time/bits/types/clock_t.h: Likewise.
* time/bits/types/struct_tm.h: Likewise.
* time/bits/types/time_t.h: Likewise.
* time/time.h: Likewise.
* wcsmbs/bits/wchar-ldbl.h: Likewise.
* wcsmbs/uchar.h: Likewise.
* wcsmbs/wchar.h: Likewise.
[_GLIBCPP_USE_NAMESPACES] (wint_t): Remove conditional definition.
* wctype/wctype.h: Do not handle C++ namespaces.
* scripts/begin-end-check.pl: Remove.
* Makefile (installed-headers): Likewise.
(tests-special): Do not add $(objpfx)begin-end-check.out.
($(objpfx)begin-end-check.out): Remove.
