1/* Copyright (C) 1991-2015 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18#ifndef _FEATURES_H
19#define _FEATURES_H 1
20
21/* These are defined by the user (or the compiler)
22 to specify the desired environment:
23
24 __STRICT_ANSI__ ISO Standard C.
25 _ISOC99_SOURCE Extensions to ISO C89 from ISO C99.
26 _ISOC11_SOURCE Extensions to ISO C99 from ISO C11.
27 _POSIX_SOURCE IEEE Std 1003.1.
28 _POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
29 if >=199309L, add IEEE Std 1003.1b-1993;
30 if >=199506L, add IEEE Std 1003.1c-1995;
31 if >=200112L, all of IEEE 1003.1-2004
32 if >=200809L, all of IEEE 1003.1-2008
33 _XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if
34 Single Unix conformance is wanted, to 600 for the
35 sixth revision, to 700 for the seventh revision.
36 _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
37 _LARGEFILE_SOURCE Some more functions for correct standard I/O.
38 _LARGEFILE64_SOURCE Additional functionality from LFS for large files.
39 _FILE_OFFSET_BITS=N Select default filesystem interface.
40 _ATFILE_SOURCE Additional *at interfaces.
41 _GNU_SOURCE All of the above, plus GNU extensions.
42 _DEFAULT_SOURCE The default set of features (taking precedence over
43 __STRICT_ANSI__).
44 _REENTRANT Select additionally reentrant object.
45 _THREAD_SAFE Same as _REENTRANT, often used by other systems.
46 _FORTIFY_SOURCE If set to numeric value > 0 additional security
47 measures are defined, according to level.
48
49 The `-ansi' switch to the GNU C compiler, and standards conformance
50 options such as `-std=c99', define __STRICT_ANSI__. If none of
51 these are defined, or if _DEFAULT_SOURCE is defined, the default is
52 to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
53 200809L, as well as enabling miscellaneous functions from BSD and
54 SVID. If more than one of these are defined, they accumulate. For
55 example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together
56 give you ISO C, 1003.1, and 1003.2, but nothing else.
57
58 These are defined by this file and are used by the
59 header files to decide what to declare or define:
60
61 __USE_ISOC11 Define ISO C11 things.
62 __USE_ISOC99 Define ISO C99 things.
63 __USE_ISOC95 Define ISO C90 AMD1 (C95) things.
64 __USE_POSIX Define IEEE Std 1003.1 things.
65 __USE_POSIX2 Define IEEE Std 1003.2 things.
66 __USE_POSIX199309 Define IEEE Std 1003.1, and .1b things.
67 __USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things.
68 __USE_XOPEN Define XPG things.
69 __USE_XOPEN_EXTENDED Define X/Open Unix things.
70 __USE_UNIX98 Define Single Unix V2 things.
71 __USE_XOPEN2K Define XPG6 things.
72 __USE_XOPEN2KXSI Define XPG6 XSI things.
73 __USE_XOPEN2K8 Define XPG7 things.
74 __USE_XOPEN2K8XSI Define XPG7 XSI things.
75 __USE_LARGEFILE Define correct standard I/O things.
76 __USE_LARGEFILE64 Define LFS things with separate names.
77 __USE_FILE_OFFSET64 Define 64bit interface as default.
78 __USE_MISC Define things from 4.3BSD or System V Unix.
79 __USE_ATFILE Define *at interfaces and AT_* constants for them.
80 __USE_GNU Define GNU extensions.
81 __USE_REENTRANT Define reentrant/thread-safe *_r functions.
82 __USE_FORTIFY_LEVEL Additional security measures used, according to level.
83
84 The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
85 defined by this file unconditionally. `__GNU_LIBRARY__' is provided
86 only for compatibility. All new code should use the other symbols
87 to test for features.
88
89 All macros listed above as possibly being defined by this file are
90 explicitly undefined if they are not explicitly defined.
91 Feature-test macros that are not defined by the user or compiler
92 but are implied by the other feature-test macros defined (or by the
93 lack of any definitions) are defined by the file. */
94
95
96/* Undefine everything, so we get a clean slate. */
97#undef __USE_ISOC11
98#undef __USE_ISOC99
99#undef __USE_ISOC95
100#undef __USE_ISOCXX11
101#undef __USE_POSIX
102#undef __USE_POSIX2
103#undef __USE_POSIX199309
104#undef __USE_POSIX199506
105#undef __USE_XOPEN
106#undef __USE_XOPEN_EXTENDED
107#undef __USE_UNIX98
108#undef __USE_XOPEN2K
109#undef __USE_XOPEN2KXSI
110#undef __USE_XOPEN2K8
111#undef __USE_XOPEN2K8XSI
112#undef __USE_LARGEFILE
113#undef __USE_LARGEFILE64
114#undef __USE_FILE_OFFSET64
115#undef __USE_MISC
116#undef __USE_ATFILE
117#undef __USE_GNU
118#undef __USE_REENTRANT
119#undef __USE_FORTIFY_LEVEL
120#undef __KERNEL_STRICT_NAMES
121
122/* Suppress kernel-name space pollution unless user expressedly asks
123 for it. */
124#ifndef _LOOSE_KERNEL_NAMES
125# define __KERNEL_STRICT_NAMES
126#endif
127
128/* Convenience macros to test the versions of glibc and gcc.
129 Use them like this:
130 #if __GNUC_PREREQ (2,8)
131 ... code requiring gcc 2.8 or later ...
132 #endif
133 Note - they won't work for gcc1 or glibc1, since the _MINOR macros
134 were not defined then. */
135#if defined __GNUC__ && defined __GNUC_MINOR__
136# define __GNUC_PREREQ(maj, min) \
137 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
138#else
139# define __GNUC_PREREQ(maj, min) 0
140#endif
141
142/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
143 _DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not
144 issue a warning; the expectation is that the source is being
145 transitioned to use the new macro. */
146#if (defined _BSD_SOURCE || defined _SVID_SOURCE) \
147 && !defined _DEFAULT_SOURCE
148# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
149# undef _DEFAULT_SOURCE
150# define _DEFAULT_SOURCE 1
151#endif
152
153/* If _GNU_SOURCE was defined by the user, turn on all the other features. */
154#ifdef _GNU_SOURCE
155# undef _ISOC95_SOURCE
156# define _ISOC95_SOURCE 1
157# undef _ISOC99_SOURCE
158# define _ISOC99_SOURCE 1
159# undef _ISOC11_SOURCE
160# define _ISOC11_SOURCE 1
161# undef _POSIX_SOURCE
162# define _POSIX_SOURCE 1
163# undef _POSIX_C_SOURCE
164# define _POSIX_C_SOURCE 200809L
165# undef _XOPEN_SOURCE
166# define _XOPEN_SOURCE 700
167# undef _XOPEN_SOURCE_EXTENDED
168# define _XOPEN_SOURCE_EXTENDED 1
169# undef _LARGEFILE64_SOURCE
170# define _LARGEFILE64_SOURCE 1
171# undef _DEFAULT_SOURCE
172# define _DEFAULT_SOURCE 1
173# undef _ATFILE_SOURCE
174# define _ATFILE_SOURCE 1
175#endif
176
177/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
178 define _DEFAULT_SOURCE. */
179#if (defined _DEFAULT_SOURCE \
180 || (!defined __STRICT_ANSI__ \
181 && !defined _ISOC99_SOURCE \
182 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \
183 && !defined _XOPEN_SOURCE))
184# undef _DEFAULT_SOURCE
185# define _DEFAULT_SOURCE 1
186#endif
187
188/* This is to enable the ISO C11 extension. */
189#if (defined _ISOC11_SOURCE \
190 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
191# define __USE_ISOC11 1
192#endif
193
194/* This is to enable the ISO C99 extension. */
195#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
196 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
197# define __USE_ISOC99 1
198#endif
199
200/* This is to enable the ISO C90 Amendment 1:1995 extension. */
201#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
202 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
203# define __USE_ISOC95 1
204#endif
205
206/* This is to enable compatibility for ISO C++11.
207
208 So far g++ does not provide a macro. Check the temporary macro for
209 now, too. */
210#if ((defined __cplusplus && __cplusplus >= 201103L) \
211 || defined __GXX_EXPERIMENTAL_CXX0X__)
212# define __USE_ISOCXX11 1
213#endif
214
215/* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE
216 is defined, use POSIX.1-2008 (or another version depending on
217 _XOPEN_SOURCE). */
218#ifdef _DEFAULT_SOURCE
219# if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE
220# define __USE_POSIX_IMPLICITLY 1
221# endif
222# undef _POSIX_SOURCE
223# define _POSIX_SOURCE 1
224# undef _POSIX_C_SOURCE
225# define _POSIX_C_SOURCE 200809L
226#endif
227#if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
228 !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
229# define _POSIX_SOURCE 1
230# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
231# define _POSIX_C_SOURCE 2
232# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
233# define _POSIX_C_SOURCE 199506L
234# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
235# define _POSIX_C_SOURCE 200112L
236# else
237# define _POSIX_C_SOURCE 200809L
238# endif
239# define __USE_POSIX_IMPLICITLY 1
240#endif
241
242#if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
243# define __USE_POSIX 1
244#endif
245
246#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
247# define __USE_POSIX2 1
248#endif
249
250#if (_POSIX_C_SOURCE - 0) >= 199309L
251# define __USE_POSIX199309 1
252#endif
253
254#if (_POSIX_C_SOURCE - 0) >= 199506L
255# define __USE_POSIX199506 1
256#endif
257
258#if (_POSIX_C_SOURCE - 0) >= 200112L
259# define __USE_XOPEN2K 1
260# undef __USE_ISOC95
261# define __USE_ISOC95 1
262# undef __USE_ISOC99
263# define __USE_ISOC99 1
264#endif
265
266#if (_POSIX_C_SOURCE - 0) >= 200809L
267# define __USE_XOPEN2K8 1
268# undef _ATFILE_SOURCE
269# define _ATFILE_SOURCE 1
270#endif
271
272#ifdef _XOPEN_SOURCE
273# define __USE_XOPEN 1
274# if (_XOPEN_SOURCE - 0) >= 500
275# define __USE_XOPEN_EXTENDED 1
276# define __USE_UNIX98 1
277# undef _LARGEFILE_SOURCE
278# define _LARGEFILE_SOURCE 1
279# if (_XOPEN_SOURCE - 0) >= 600
280# if (_XOPEN_SOURCE - 0) >= 700
281# define __USE_XOPEN2K8 1
282# define __USE_XOPEN2K8XSI 1
283# endif
284# define __USE_XOPEN2K 1
285# define __USE_XOPEN2KXSI 1
286# undef __USE_ISOC95
287# define __USE_ISOC95 1
288# undef __USE_ISOC99
289# define __USE_ISOC99 1
290# endif
291# else
292# ifdef _XOPEN_SOURCE_EXTENDED
293# define __USE_XOPEN_EXTENDED 1
294# endif
295# endif
296#endif
297
298#ifdef _LARGEFILE_SOURCE
299# define __USE_LARGEFILE 1
300#endif
301
302#ifdef _LARGEFILE64_SOURCE
303# define __USE_LARGEFILE64 1
304#endif
305
306#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
307# define __USE_FILE_OFFSET64 1
308#endif
309
310#if defined _DEFAULT_SOURCE
311# define __USE_MISC 1
312#endif
313
314#ifdef _ATFILE_SOURCE
315# define __USE_ATFILE 1
316#endif
317
318#ifdef _GNU_SOURCE
319# define __USE_GNU 1
320#endif
321
322#if defined _REENTRANT || defined _THREAD_SAFE
323# define __USE_REENTRANT 1
324#endif
325
326#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
327# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
328# warning _FORTIFY_SOURCE requires compiling with optimization (-O)
329# elif !__GNUC_PREREQ (4, 1)
330# warning _FORTIFY_SOURCE requires GCC 4.1 or later
331# elif _FORTIFY_SOURCE > 1
332# define __USE_FORTIFY_LEVEL 2
333# else
334# define __USE_FORTIFY_LEVEL 1
335# endif
336#endif
337#ifndef __USE_FORTIFY_LEVEL
338# define __USE_FORTIFY_LEVEL 0
339#endif
340
341/* Get definitions of __STDC_* predefined macros, if the compiler has
342 not preincluded this header automatically. */
343#include <stdc-predef.h>
344
345/* This macro indicates that the installed library is the GNU C Library.
346 For historic reasons the value now is 6 and this will stay from now
347 on. The use of this variable is deprecated. Use __GLIBC__ and
348 __GLIBC_MINOR__ now (see below) when you want to test for a specific
349 GNU C library version and use the values in <gnu/lib-names.h> to get
350 the sonames of the shared libraries. */
351#undef __GNU_LIBRARY__
352#define __GNU_LIBRARY__ 6
353
354/* Major and minor version number of the GNU C library package. Use
355 these macros to test for features in specific releases. */
356#define __GLIBC__ 2
357#define __GLIBC_MINOR__ 22
358
359#define __GLIBC_PREREQ(maj, min) \
360 ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
361
362/* This is here only because every header file already includes this one. */
363#ifndef __ASSEMBLER__
364# ifndef _SYS_CDEFS_H
365# include <sys/cdefs.h>
366# endif
367
368/* If we don't have __REDIRECT, prototypes will be missing if
369 __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
370# if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
371# define __USE_LARGEFILE 1
372# define __USE_LARGEFILE64 1
373# endif
374
375#endif /* !ASSEMBLER */
376
377/* Decide whether we can define 'extern inline' functions in headers. */
378#if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
379 && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
380 && defined __extern_inline
381# define __USE_EXTERN_INLINES 1
382#endif
383
384
385/* This is here only because every header file already includes this one.
386 Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
387 <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
388 that will always return failure (and set errno to ENOSYS). */
389#include <gnu/stubs.h>
390
391
392#endif /* features.h */
393