diff options
Diffstat (limited to 'include/features.h')
-rw-r--r-- | include/features.h | 108 |
1 files changed, 84 insertions, 24 deletions
diff --git a/include/features.h b/include/features.h index 9514d35718..5bed0a4996 100644 --- a/include/features.h +++ b/include/features.h @@ -1,4 +1,4 @@ -/* Copyright (C) 1991-2016 Free Software Foundation, Inc. +/* Copyright (C) 1991-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -24,6 +24,15 @@ __STRICT_ANSI__ ISO Standard C. _ISOC99_SOURCE Extensions to ISO C89 from ISO C99. _ISOC11_SOURCE Extensions to ISO C99 from ISO C11. + __STDC_WANT_LIB_EXT2__ + Extensions to ISO C99 from TR 27431-2:2010. + __STDC_WANT_IEC_60559_BFP_EXT__ + Extensions to ISO C11 from TS 18661-1:2014. + __STDC_WANT_IEC_60559_FUNCS_EXT__ + Extensions to ISO C11 from TS 18661-4:2015. + __STDC_WANT_IEC_60559_TYPES_EXT__ + Extensions to ISO C11 from TS 18661-3:2015. + _POSIX_SOURCE IEEE Std 1003.1. _POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2; if >=199309L, add IEEE Std 1003.1b-1993; @@ -41,10 +50,12 @@ _GNU_SOURCE All of the above, plus GNU extensions. _DEFAULT_SOURCE The default set of features (taking precedence over __STRICT_ANSI__). - _REENTRANT Select additionally reentrant object. - _THREAD_SAFE Same as _REENTRANT, often used by other systems. - _FORTIFY_SOURCE If set to numeric value > 0 additional security - measures are defined, according to level. + + _FORTIFY_SOURCE Add security hardening to many library functions. + Set to 1 or 2; 2 performs stricter checks than 1. + + _REENTRANT, _THREAD_SAFE + Obsolete; equivalent to _POSIX_C_SOURCE=199506L. The `-ansi' switch to the GNU C compiler, and standards conformance options such as `-std=c99', define __STRICT_ANSI__. If none of @@ -58,9 +69,14 @@ These are defined by this file and are used by the header files to decide what to declare or define: + __GLIBC_USE (F) Define things from feature set F. This is defined + to 1 or 0; the subsequent macros are either defined + or undefined, and those tests should be moved to + __GLIBC_USE. __USE_ISOC11 Define ISO C11 things. __USE_ISOC99 Define ISO C99 things. __USE_ISOC95 Define ISO C90 AMD1 (C95) things. + __USE_ISOCXX11 Define ISO C++11 things. __USE_POSIX Define IEEE Std 1003.1 things. __USE_POSIX2 Define IEEE Std 1003.2 things. __USE_POSIX199309 Define IEEE Std 1003.1, and .1b things. @@ -78,7 +94,6 @@ __USE_MISC Define things from 4.3BSD or System V Unix. __USE_ATFILE Define *at interfaces and AT_* constants for them. __USE_GNU Define GNU extensions. - __USE_REENTRANT Define reentrant/thread-safe *_r functions. __USE_FORTIFY_LEVEL Additional security measures used, according to level. The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are @@ -90,7 +105,14 @@ explicitly undefined if they are not explicitly defined. Feature-test macros that are not defined by the user or compiler but are implied by the other feature-test macros defined (or by the - lack of any definitions) are defined by the file. */ + lack of any definitions) are defined by the file. + + ISO C feature test macros depend on the definition of the macro + when an affected header is included, not when the first system + header is included, and so they are handled in + <bits/libc-header-start.h>, which does not have a multiple include + guard. Feature test macros that can be handled from the first + system header included are handled here. */ /* Undefine everything, so we get a clean slate. */ @@ -115,9 +137,9 @@ #undef __USE_MISC #undef __USE_ATFILE #undef __USE_GNU -#undef __USE_REENTRANT #undef __USE_FORTIFY_LEVEL #undef __KERNEL_STRICT_NAMES +#undef __GLIBC_USE_DEPRECATED_GETS /* Suppress kernel-name space pollution unless user expressedly asks for it. */ @@ -125,13 +147,13 @@ # define __KERNEL_STRICT_NAMES #endif -/* Convenience macros to test the versions of glibc and gcc. - Use them like this: +/* Convenience macro to test the version of gcc. + Use like this: #if __GNUC_PREREQ (2,8) ... code requiring gcc 2.8 or later ... #endif - Note - they won't work for gcc1 or glibc1, since the _MINOR macros - were not defined then. */ + Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was + added in 2.0. */ #if defined __GNUC__ && defined __GNUC_MINOR__ # define __GNUC_PREREQ(maj, min) \ ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) @@ -139,6 +161,20 @@ # define __GNUC_PREREQ(maj, min) 0 #endif +/* Similarly for clang. Features added to GCC after version 4.2 may + or may not also be available in clang, and clang's definitions of + __GNUC(_MINOR)__ are fixed at 4 and 2 respectively. Not all such + features can be queried via __has_extension/__has_feature. */ +#if defined __clang_major__ && defined __clang_minor__ +# define __glibc_clang_prereq(maj, min) \ + ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min)) +#else +# define __glibc_clang_prereq(maj, min) 0 +#endif + +/* Whether to use feature set F. */ +#define __GLIBC_USE(F) __GLIBC_USE_ ## F + /* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for _DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not issue a warning; the expectation is that the source is being @@ -178,7 +214,7 @@ define _DEFAULT_SOURCE. */ #if (defined _DEFAULT_SOURCE \ || (!defined __STRICT_ANSI__ \ - && !defined _ISOC99_SOURCE \ + && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \ && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \ && !defined _XOPEN_SOURCE)) # undef _DEFAULT_SOURCE @@ -203,13 +239,17 @@ # define __USE_ISOC95 1 #endif +#ifdef __cplusplus +/* This is to enable compatibility for ISO C++17. */ +# if __cplusplus >= 201703L +# define __USE_ISOC11 1 +# endif /* This is to enable compatibility for ISO C++11. - - So far g++ does not provide a macro. Check the temporary macro for - now, too. */ -#if ((defined __cplusplus && __cplusplus >= 201103L) \ - || defined __GXX_EXPERIMENTAL_CXX0X__) -# define __USE_ISOCXX11 1 + Check the temporary macro for now, too. */ +# if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__ +# define __USE_ISOCXX11 1 +# define __USE_ISOC99 1 +# endif #endif /* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE @@ -224,6 +264,7 @@ # undef _POSIX_C_SOURCE # define _POSIX_C_SOURCE 200809L #endif + #if ((!defined __STRICT_ANSI__ \ || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \ && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE) @@ -240,6 +281,19 @@ # define __USE_POSIX_IMPLICITLY 1 #endif +/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be + defined in all multithreaded code. GNU libc has not required this + for many years. We now treat them as compatibility synonyms for + _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with + comprehensive support for multithreaded code. Using them never + lowers the selected level of POSIX conformance, only raises it. */ +#if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \ + && (defined _REENTRANT || defined _THREAD_SAFE)) +# define _POSIX_SOURCE 1 +# undef _POSIX_C_SOURCE +# define _POSIX_C_SOURCE 199506L +#endif + #if (defined _POSIX_SOURCE \ || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \ || defined _XOPEN_SOURCE) @@ -322,10 +376,6 @@ # define __USE_GNU 1 #endif -#if defined _REENTRANT || defined _THREAD_SAFE -# define __USE_REENTRANT 1 -#endif - #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 # if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0 # warning _FORTIFY_SOURCE requires compiling with optimization (-O) @@ -341,6 +391,16 @@ # define __USE_FORTIFY_LEVEL 0 #endif +/* The function 'gets' existed in C89, but is impossible to use + safely. It has been removed from ISO C11 and ISO C++14. Note: for + compatibility with various implementations of <cstdio>, this test + must consider only the value of __cplusplus when compiling C++. */ +#if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11 +# define __GLIBC_USE_DEPRECATED_GETS 0 +#else +# define __GLIBC_USE_DEPRECATED_GETS 1 +#endif + /* Get definitions of __STDC_* predefined macros, if the compiler has not preincluded this header automatically. */ #include <stdc-predef.h> @@ -357,7 +417,7 @@ /* Major and minor version number of the GNU C library package. Use these macros to test for features in specific releases. */ #define __GLIBC__ 2 -#define __GLIBC_MINOR__ 23 +#define __GLIBC_MINOR__ 28 #define __GLIBC_PREREQ(maj, min) \ ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min)) |