From patchwork Fri Aug 9 17:05:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Myers X-Patchwork-Id: 34018 Received: (qmail 62362 invoked by alias); 9 Aug 2019 17:06:08 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 62330 invoked by uid 89); 9 Aug 2019 17:06:08 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-15.1 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_PASS autolearn=ham version=3.3.1 spammy=C90, c90, H*i:sk:87r25uz, H*f:sk:87r25uz X-HELO: esa1.mentor.iphmx.com IronPort-SDR: kur84kK7WTstcDMW0OIkhKaBBdjXQiJVMTHeFbzC9QpMXv3g9nvHh2NLOYtB1EEBGGn6/dxbd6 jKFJX+xMLgNbTuEerwTCfOCi8njSsXYXlKuy/a42fQ/90cUy86Wo5rKVkdwr5iUCpEU1uhyeRd B5FWS4WMBF8RFjpDgoIyYE+CsWSRvRKap3KVm+yHo/26r0YFa72ooPI2jiwbvDPK6Ky5DsEIBE 4ni2RU7zWzrWoYTcF0cK+Httl8QXevSC2b1/0z9U6GdnQ5siSO4+AaRhAxO0591XAEJUDhva7H gis= IronPort-SDR: hGF90IAEkkRkJlnp6I1UHqOCFnW/CyNh4BCOo5rDval31qgFC9lgS6xmuq3ymBOcV07qfT7SL0 oyp5FsaSip0Far8SFDWO1D3Zjrb1It3jaf7lBpM0xvMEFYLuvk8CUkUdTyPpOh5B81YMuYc4Hz VPvp7jA+Q0u9MYPGNju3pjPAj/bAoB4iiGT24fKiGLIKRv0csIz9l7BD8lP2Q4roj72SJ5A5a4 QwXxaFB7vO5NWzcrErFi9YS2Uuhrre4FJf9MXhlM+pgBP2S5COctKklwv7r6p5I9H31auCinKC +Rk= Date: Fri, 9 Aug 2019 17:05:59 +0000 From: Joseph Myers To: Florian Weimer CC: Subject: Re: Add feature test macro _ISOC2X_SOURCE In-Reply-To: <87r25uz6t5.fsf@oldenburg2.str.redhat.com> Message-ID: References: <87k1bm6c99.fsf@oldenburg2.str.redhat.com> <87r25uz6t5.fsf@oldenburg2.str.redhat.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Return-Path: joseph@codesourcery.com On Fri, 9 Aug 2019, Florian Weimer wrote: > Regarding the actual patch, do you expect _ISOC2X_SOURCE to enable C11 > and earlier extensions? If not, why not? Here is a version that makes it also enable all the earlier C standard versions. Add feature test macro _ISOC2X_SOURCE. This patch starts preparation for C2X support in glibc headers by adding a feature test macro _ISOC2X_SOURCE and corresponding __GLIBC_USE (ISOC2X). (I chose to use the newer __GLIBC_USE style for this rather than the older __USE_* macros tested with #ifdef.) As with other such macros, C2X features are also enabled by compiling for a standard newer than C17, or by using _GNU_SOURCE. This patch does not itself enable anything new in the headers for C2X; that is to be done in followup patches. (For example, most of the TS 18661-1 functions should be declared for C2X without any __STDC_WANT_IEC_60559_BFP_EXT__ being needed, but the ones that 18661-1 adds to Annex F because of their close relation to IEEE 754 formats do still need the WANT macro in C2X.) Once C2X becomes an actual standard we'll presumably move to using the actual year in the feature test macro and __GLIBC_USE, with some period when both macro spellings are accepted, as was done with _ISOC9X_SOURCE. Tested for x86_64. 2019-08-09 Joseph Myers * include/features.h (_ISOC2X_SOURCE): New feature test macro. Undefine and define to 1 if [_GNU_SOURCE]. (__GLIBC_USE_ISOC2X): New macro. Undefine and redefine depending on [_ISOC2X_SOURCE] and [__STDC_VERSION__ > 201710L]. (__USE_ISOC11): Also define to 1 if [_ISOC2X_SOURCE]. (__USE_ISOC99): Likewise. (__USE_ISOC95): Likewise. * manual/creature.texi (_ISOC2X_SOURCE): Document. diff --git a/NEWS b/NEWS index 4326997ddd..8ca7585c2c 100644 --- a/NEWS +++ b/NEWS @@ -9,7 +9,12 @@ Version 2.31 Major new features: - [Add new features here] +* The GNU C Library now supports a feature test macro _ISOC2X_SOURCE to + enable features from the draft ISO C2X standard. Only some features from + this draft standard are supported by the GNU C Library, and as the draft + is under active development, the set of features enabled by this macro is + liable to change. Features from C2X are also enabled by _GNU_SOURCE, or + by compiling with "gcc -std=gnu2x". Deprecated and removed features, and other changes affecting compatibility: diff --git a/include/features.h b/include/features.h index bf47d881dd..8187539581 100644 --- a/include/features.h +++ b/include/features.h @@ -24,6 +24,7 @@ __STRICT_ANSI__ ISO Standard C. _ISOC99_SOURCE Extensions to ISO C89 from ISO C99. _ISOC11_SOURCE Extensions to ISO C99 from ISO C11. + _ISOC2X_SOURCE Extensions to ISO C99 from ISO C2X. __STDC_WANT_LIB_EXT2__ Extensions to ISO C99 from TR 27431-2:2010. __STDC_WANT_IEC_60559_BFP_EXT__ @@ -139,6 +140,7 @@ #undef __USE_GNU #undef __USE_FORTIFY_LEVEL #undef __KERNEL_STRICT_NAMES +#undef __GLIBC_USE_ISOC2X #undef __GLIBC_USE_DEPRECATED_GETS #undef __GLIBC_USE_DEPRECATED_SCANF @@ -195,6 +197,8 @@ # define _ISOC99_SOURCE 1 # undef _ISOC11_SOURCE # define _ISOC11_SOURCE 1 +# undef _ISOC2X_SOURCE +# define _ISOC2X_SOURCE 1 # undef _POSIX_SOURCE # define _POSIX_SOURCE 1 # undef _POSIX_C_SOURCE @@ -216,26 +220,37 @@ #if (defined _DEFAULT_SOURCE \ || (!defined __STRICT_ANSI__ \ && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \ + && !defined _ISOC2X_SOURCE \ && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \ && !defined _XOPEN_SOURCE)) # undef _DEFAULT_SOURCE # define _DEFAULT_SOURCE 1 #endif +/* This is to enable the ISO C2X extension. */ +#if (defined _ISOC2X_SOURCE \ + || (defined __STDC_VERSION__ && __STDC_VERSION__ > 201710L)) +# define __GLIBC_USE_ISOC2X 1 +#else +# define __GLIBC_USE_ISOC2X 0 +#endif + /* This is to enable the ISO C11 extension. */ -#if (defined _ISOC11_SOURCE \ +#if (defined _ISOC11_SOURCE || defined _ISOC2X_SOURCE \ || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L)) # define __USE_ISOC11 1 #endif /* This is to enable the ISO C99 extension. */ -#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ +#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ + || defined _ISOC2X_SOURCE \ || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)) # define __USE_ISOC99 1 #endif /* This is to enable the ISO C90 Amendment 1:1995 extension. */ -#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ +#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ + || defined _ISOC2X_SOURCE \ || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L)) # define __USE_ISOC95 1 #endif diff --git a/manual/creature.texi b/manual/creature.texi index 8876b2ab77..be5050468b 100644 --- a/manual/creature.texi +++ b/manual/creature.texi @@ -177,6 +177,13 @@ when the compiler uses an earlier language version. If this macro is defined, ISO C11 extensions to ISO C99 are included. @end defvr +@defvr Macro _ISOC2X_SOURCE +@standards{C2X, (none)} +If this macro is defined, ISO C2X extensions to ISO C11 are included. +Only some features from this draft standard are supported by +@theglibc{}. +@end defvr + @defvr Macro __STDC_WANT_LIB_EXT2__ @standards{ISO, (none)} If you define this macro to the value @code{1}, features from ISO/IEC