Date: Fri, 15 Nov 2024 02:02:08 GMT From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 4afcb821938f - main - cdefs: Support _ISOC23_SOURCE and --std=c23 Message-ID: <202411150202.4AF228AN047810@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=4afcb821938f5e8cb50e3a781f0276c4f5357b1a commit 4afcb821938f5e8cb50e3a781f0276c4f5357b1a Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2024-11-14 23:52:35 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2024-11-15 01:58:17 +0000 cdefs: Support _ISOC23_SOURCE and --std=c23 If either _ISOC23_SOURCE is defined or --std=c23 (or higher) is specified, then default to the making the ISO C visibility to 2023. This mirrors what glibc does, so update the comment for this change to _ISOCxx_SOURCE values. We currently implement xx = 11 or 23. C17 added no new defines or symbols, so we follow glibc's lead and ommit it. However, we don't implement the C95, C99 or C2y versions. These are non-standard and the first two don't seem to be relevant, and the latter is also experimental. Sponsored by: Netflix Reviewed by: brooks Differential Revision: https://reviews.freebsd.org/D47576 --- sys/sys/cdefs.h | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h index 25248bd235b2..1a1705129fa6 100644 --- a/sys/sys/cdefs.h +++ b/sys/sys/cdefs.h @@ -567,14 +567,21 @@ #define __POSIX_VISIBLE 198808 #define __ISO_C_VISIBLE 0 #endif /* _POSIX_C_SOURCE */ + /* - * Both glibc and OpenBSD enable c11 features when _ISOC11_SOURCE is defined, or - * when compiling with -stdc=c11. A strict reading of the standard would suggest - * doing it only for the former. However, a strict reading also requires C99 - * mode only, so building with C11 is already undefined. Follow glibc's and - * OpenBSD's lead for this non-standard configuration for maximum compatibility. + * When we've explicitly asked for a newer C version, make the C variable + * visible by default. Also honor the glibc _ISOC{11,23}_SOURCE macros + * extensions. Both glibc and OpenBSD do this, even when a more strict + * _POSIX_C_SOURCE has been requested, and it makes good sense (especially for + * pre POSIX 2024, since C11 is much nicer than the old C99 base). Continue the + * practice with C23, though don't do older standards. Also, GLIBC doesn't have + * a _ISOC17_SOURCE, so it's not implemented here. glibc has earlier ISOCxx defines, + * but we don't implement those as they are not relevant enough. */ -#if _ISOC11_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) +#if _ISOC23_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) +#undef __ISO_C_VISIBLE +#define __ISO_C_VISIBLE 2023 +#elif _ISOC11_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) #undef __ISO_C_VISIBLE #define __ISO_C_VISIBLE 2011 #endif
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