include/features.h

   1 /* Copyright (C) 1991-1993,1995-2006,2007,2009 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    _POSIX_SOURCE        IEEE Std 1003.1.
  27    _POSIX_C_SOURCE      If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
  28                         if >=199309L, add IEEE Std 1003.1b-1993;
  29                         if >=199506L, add IEEE Std 1003.1c-1995;
  30                         if >=200112L, all of IEEE 1003.1-2004
  31                         if >=200809L, all of IEEE 1003.1-2008
  32    _XOPEN_SOURCE        Includes POSIX and XPG things.  Set to 500 if
  33                         Single Unix conformance is wanted, to 600 for the
  34                         sixth revision, to 700 for the seventh revision.
  35    _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  36    _LARGEFILE_SOURCE    Some more functions for correct standard I/O.
  37    _LARGEFILE64_SOURCE  Additional functionality from LFS for large files.
  38    _FILE_OFFSET_BITS=N  Select default filesystem interface.
  39    _BSD_SOURCE          ISO C, POSIX, and 4.3BSD things.
  40    _SVID_SOURCE         ISO C, POSIX, and SVID things.
  41    _ATFILE_SOURCE       Additional *at interfaces.
  42    _GNU_SOURCE          All of the above, plus GNU extensions.
  43    _REENTRANT           Select additionally reentrant object.
  44    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  45    _FORTIFY_SOURCE      If set to numeric value > 0 additional security
  46                         measures are defined, according to level.
  47
  48    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  49    If none of these are defined, the default is to have _SVID_SOURCE,
  50    _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
  51    200112L.  If more than one of these are defined, they accumulate.
  52    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  53    together give you ISO C, 1003.1, and 1003.2, but nothing else.
  54
  55    These are defined by this file and are used by the
  56    header files to decide what to declare or define:
  57
  58    __USE_ISOC99         Define ISO C99 things.
  59    __USE_ISOC95         Define ISO C90 AMD1 (C95) things.
  60    __USE_POSIX          Define IEEE Std 1003.1 things.
  61    __USE_POSIX2         Define IEEE Std 1003.2 things.
  62    __USE_POSIX199309    Define IEEE Std 1003.1, and .1b things.
  63    __USE_POSIX199506    Define IEEE Std 1003.1, .1b, .1c and .1i things.
  64    __USE_XOPEN          Define XPG things.
  65    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  66    __USE_UNIX98         Define Single Unix V2 things.
  67    __USE_XOPEN2K        Define XPG6 things.
  68    __USE_XOPEN2K8       Define XPG7 things.
  69    __USE_LARGEFILE      Define correct standard I/O things.
  70    __USE_LARGEFILE64    Define LFS things with separate names.
  71    __USE_FILE_OFFSET64  Define 64bit interface as default.
  72    __USE_BSD            Define 4.3BSD things.
  73    __USE_SVID           Define SVID things.
  74    __USE_MISC           Define things common to BSD and System V Unix.
  75    __USE_ATFILE         Define *at interfaces and AT_* constants for them.
  76    __USE_GNU            Define GNU extensions.
  77    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  78    __USE_FORTIFY_LEVEL  Additional security measures used, according to level.
  79    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  80
  81    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  82    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  83    only for compatibility.  All new code should use the other symbols
  84    to test for features.
  85
  86    All macros listed above as possibly being defined by this file are
  87    explicitly undefined if they are not explicitly defined.
  88    Feature-test macros that are not defined by the user or compiler
  89    but are implied by the other feature-test macros defined (or by the
  90    lack of any definitions) are defined by the file.  */
  91
  92
  93 /* Undefine everything, so we get a clean slate.  */
  94 #undef  __USE_ISOC99
  95 #undef  __USE_ISOC95
  96 #undef  __USE_POSIX
  97 #undef  __USE_POSIX2
  98 #undef  __USE_POSIX199309
  99 #undef  __USE_POSIX199506
 100 #undef  __USE_XOPEN
 101 #undef  __USE_XOPEN_EXTENDED
 102 #undef  __USE_UNIX98
 103 #undef  __USE_XOPEN2K
 104 #undef  __USE_XOPEN2K8
 105 #undef  __USE_LARGEFILE
 106 #undef  __USE_LARGEFILE64
 107 #undef  __USE_FILE_OFFSET64
 108 #undef  __USE_BSD
 109 #undef  __USE_SVID
 110 #undef  __USE_MISC
 111 #undef  __USE_ATFILE
 112 #undef  __USE_GNU
 113 #undef  __USE_REENTRANT
 114 #undef  __USE_FORTIFY_LEVEL
 115 #undef  __FAVOR_BSD
 116 #undef  __KERNEL_STRICT_NAMES
 117
 118 /* Suppress kernel-name space pollution unless user expressedly asks
 119    for it.  */
 120 #ifndef _LOOSE_KERNEL_NAMES
 121 # define __KERNEL_STRICT_NAMES
 122 #endif
 123
 124 /* Always use ISO C things.  */
 125 #define __USE_ANSI      1
 126
 127 /* Convenience macros to test the versions of glibc and gcc.
 128    Use them like this:
 129    #if __GNUC_PREREQ (2,8)
 130    ... code requiring gcc 2.8 or later ...
 131    #endif
 132    Note - they won't work for gcc1 or glibc1, since the _MINOR macros
 133    were not defined then.  */
 134 #if defined __GNUC__ && defined __GNUC_MINOR__
 135 # define __GNUC_PREREQ(maj, min) \
 136         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
 137 #else
 138 # define __GNUC_PREREQ(maj, min) 0
 139 #endif
 140
 141
 142 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 143 #if defined _BSD_SOURCE && \
 144     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 145       defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
 146       defined _GNU_SOURCE || defined _SVID_SOURCE)
 147 # define __FAVOR_BSD    1
 148 #endif
 149
 150 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 151 #ifdef _GNU_SOURCE
 152 # undef  _ISOC99_SOURCE
 153 # define _ISOC99_SOURCE 1
 154 # undef  _POSIX_SOURCE
 155 # define _POSIX_SOURCE  1
 156 # undef  _POSIX_C_SOURCE
 157 # define _POSIX_C_SOURCE        200809L
 158 # undef  _XOPEN_SOURCE
 159 # define _XOPEN_SOURCE  700
 160 # undef  _XOPEN_SOURCE_EXTENDED
 161 # define _XOPEN_SOURCE_EXTENDED 1
 162 # undef  _LARGEFILE64_SOURCE
 163 # define _LARGEFILE64_SOURCE    1
 164 # undef  _BSD_SOURCE
 165 # define _BSD_SOURCE    1
 166 # undef  _SVID_SOURCE
 167 # define _SVID_SOURCE   1
 168 # undef  _ATFILE_SOURCE
 169 # define _ATFILE_SOURCE 1
 170 #endif
 171
 172 /* This macro indicates that the installed library is uClibc.  Use
 173  * __UCLIBC_MAJOR__ and __UCLIBC_MINOR__ to test for the features in
 174  * specific releases.  */
 175 #define __UCLIBC__              1
 176
 177 #ifdef __UCLIBC__
 178 /* Load up the current set of uClibc supported features along
 179  * with the current uClibc major and minor version numbers.
 180  * For uClibc release 0.9.26, these numbers would be:
 181  *      #define __UCLIBC_MAJOR__        0
 182  *      #define __UCLIBC_MINOR__        9
 183  *      #define __UCLIBC_SUBLEVEL__     26
 184  */
 185 # define __need_uClibc_config_h
 186 # include <bits/uClibc_config.h>
 187 # undef __need_uClibc_config_h
 188
 189 /* For uClibc, always optimize for size -- this should disable
 190  * a lot of expensive inlining...
 191  * TODO: this is wrong! __OPTIMIZE_SIZE__ is an indicator of
 192  * gcc -Os compile. We should not mess with compiler inlines.
 193  * We should instead disable __USE_EXTERN_INLINES unconditionally,
 194  * or maybe actually audit and test uclibc to work correctly
 195  * with __USE_EXTERN_INLINES on.
 196  */
 197 # define __OPTIMIZE_SIZE__   1
 198
 199 /* disable unsupported features */
 200 # undef __LDBL_COMPAT
 201
 202 # ifndef __UCLIBC_HAS_FORTIFY__
 203 #  undef _FORTIFY_SOURCE
 204 # endif
 205
 206 # ifndef __UCLIBC_HAS_THREADS__
 207 #  if defined _REENTRANT || defined _THREAD_SAFE
 208 #   warning requested reentrant code, but thread support was disabled
 209 #   undef _REENTRANT
 210 #   undef _THREAD_SAFE
 211 #  endif
 212 # endif
 213
 214 #endif /* __UCLIBC__ */
 215
 216 /* If nothing (other than _GNU_SOURCE) is defined,
 217    define _BSD_SOURCE and _SVID_SOURCE.  */
 218 #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
 219      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 220      !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
 221      !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 222 # define _BSD_SOURCE    1
 223 # define _SVID_SOURCE   1
 224 #endif
 225
 226 /* This is to enable the ISO C99 extension.  Also recognize the old macro
 227    which was used prior to the standard acceptance.  This macro will
 228    eventually go away and the features enabled by default once the ISO C99
 229    standard is widely adopted.  */
 230 #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
 231      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
 232 # define __USE_ISOC99   1
 233 #endif
 234
 235 /* This is to enable the ISO C90 Amendment 1:1995 extension.  */
 236 #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
 237      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
 238 # define __USE_ISOC95   1
 239 #endif
 240
 241 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 242    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 243 #if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
 244      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
 245 # define _POSIX_SOURCE  1
 246 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
 247 #  define _POSIX_C_SOURCE       2
 248 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
 249 #  define _POSIX_C_SOURCE       199506L
 250 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
 251 #  define _POSIX_C_SOURCE       200112L
 252 # else
 253 #  define _POSIX_C_SOURCE       200809L
 254 # endif
 255 # define __USE_POSIX_IMPLICITLY 1
 256 #endif
 257
 258 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 259 # define __USE_POSIX    1
 260 #endif
 261
 262 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 263 # define __USE_POSIX2   1
 264 #endif
 265
 266 #if (_POSIX_C_SOURCE - 0) >= 199309L
 267 # define __USE_POSIX199309      1
 268 #endif
 269
 270 #if (_POSIX_C_SOURCE - 0) >= 199506L
 271 # define __USE_POSIX199506      1
 272 #endif
 273
 274 #if (_POSIX_C_SOURCE - 0) >= 200112L
 275 # define __USE_XOPEN2K          1
 276 # undef __USE_ISOC99
 277 # define __USE_ISOC99           1
 278 #endif
 279
 280 #if (_POSIX_C_SOURCE - 0) >= 200809L
 281 # define __USE_XOPEN2K8         1
 282 # undef  _ATFILE_SOURCE
 283 # define _ATFILE_SOURCE 1
 284 #endif
 285
 286 #ifdef  _XOPEN_SOURCE
 287 # define __USE_XOPEN    1
 288 # if (_XOPEN_SOURCE - 0) >= 500
 289 #  define __USE_XOPEN_EXTENDED  1
 290 #  define __USE_UNIX98  1
 291 #  undef _LARGEFILE_SOURCE
 292 #  define _LARGEFILE_SOURCE     1
 293 #  if (_XOPEN_SOURCE - 0) >= 600
 294 #   if (_XOPEN_SOURCE - 0) >= 700
 295 #    define __USE_XOPEN2K8      1
 296 #   endif
 297 #   define __USE_XOPEN2K        1
 298 #   undef __USE_ISOC99
 299 #   define __USE_ISOC99         1
 300 #  endif
 301 # else
 302 #  ifdef _XOPEN_SOURCE_EXTENDED
 303 #   define __USE_XOPEN_EXTENDED 1
 304 #  endif
 305 # endif
 306 #endif
 307
 308 #ifdef _LARGEFILE_SOURCE
 309 # define __USE_LARGEFILE        1
 310 #endif
 311
 312 #ifdef _LARGEFILE64_SOURCE
 313 # define __USE_LARGEFILE64      1
 314 #endif
 315
 316 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 317 # define __USE_FILE_OFFSET64    1
 318 #endif
 319
 320 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 321 # define __USE_MISC     1
 322 #endif
 323
 324 #ifdef  _BSD_SOURCE
 325 # define __USE_BSD      1
 326 #endif
 327
 328 #ifdef  _SVID_SOURCE
 329 # define __USE_SVID     1
 330 #endif
 331
 332 #ifdef  _ATFILE_SOURCE
 333 # define __USE_ATFILE   1
 334 #endif
 335
 336 #ifdef  _GNU_SOURCE
 337 # define __USE_GNU      1
 338 #endif
 339
 340 #if defined _REENTRANT || defined _THREAD_SAFE
 341 # define __USE_REENTRANT        1
 342 #endif
 343
 344 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \
 345     && __GNUC_PREREQ (4, 1) && defined __OPTIMIZE__ && __OPTIMIZE__ > 0
 346 # if _FORTIFY_SOURCE > 1
 347 #  define __USE_FORTIFY_LEVEL 2
 348 # else
 349 #  define __USE_FORTIFY_LEVEL 1
 350 # endif
 351 #else
 352 # define __USE_FORTIFY_LEVEL 0
 353 #endif
 354
 355 /* We do support the IEC 559 math functionality, real and complex.  */
 356 #ifdef __UCLIBC_HAS_FLOATS__
 357 #define __STDC_IEC_559__                1
 358 #define __STDC_IEC_559_COMPLEX__        1
 359 #endif
 360
 361 #ifdef __UCLIBC_HAS_WCHAR__
 362 /* wchar_t uses ISO 10646-1 (2nd ed., published 2000-09-15) / Unicode 3.1.  */
 363 #define __STDC_ISO_10646__              200009L
 364 #endif
 365
 366 /*  There is an unwholesomely huge amount of code out there that depends on the
 367  *  presence of GNU libc header files.  We have GNU libc header files.  So here
 368  *  we commit a horrible sin.  At this point, we _lie_ and claim to be GNU libc
 369  *  to make things like /usr/include/linux/socket.h and lots of apps work as
 370  *  their developers intended.  This is IMHO, pardonable, since these defines
 371  *  are not really intended to check for the presence of a particular library,
 372  *  but rather are used to define an _interface_.  */
 373 #if !defined __FORCE_NOGLIBC && (!defined _LIBC || defined __FORCE_GLIBC)
 374 /* This macro indicates that the installed library is the GNU C Library.
 375    For historic reasons the value now is 6 and this will stay from now
 376    on.  The use of this variable is deprecated.  */
 377 /* uClibc WARNING: leave these aligned to the left, don't put a space after '#', else
 378  * broken apps could fail the check. */
 379 #undef  __GNU_LIBRARY__
 380 #define __GNU_LIBRARY__ 6
 381
 382 /* Major and minor version number of the GNU C library package.  Use
 383    these macros to test for features in specific releases.  */
 384 /* Don't do it, if you want to keep uClibc happy.  */
 385 #define __GLIBC__       2
 386 #define __GLIBC_MINOR__ 2
 387 #endif
 388
 389 #define __GLIBC_PREREQ(maj, min) \
 390         ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
 391
 392 #ifndef __UCLIBC__
 393 /* Decide whether a compiler supports the long long datatypes.  */
 394 #if defined __GNUC__ \
 395     || (defined __PGI && defined __i386__ ) \
 396     || (defined __INTEL_COMPILER && (defined __i386__ || defined __ia64__)) \
 397     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
 398 # define __GLIBC_HAVE_LONG_LONG 1
 399 #endif
 400 #endif
 401
 402 /* This is here only because every header file already includes this one.  */
 403 #ifndef __ASSEMBLER__
 404 # ifndef _SYS_CDEFS_H
 405 #  include <sys/cdefs.h>
 406 # endif
 407
 408 /* If we don't have __REDIRECT, prototypes will be missing if
 409    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 410 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 411 #  define __USE_LARGEFILE       1
 412 #  define __USE_LARGEFILE64     1
 413 # endif
 414
 415 #endif  /* !ASSEMBLER */
 416
 417 /* Decide whether we can, and are willing to define extern inline
 418  * functions in headers, even if this results in a slightly bigger
 419  * code for user programs built against uclibc.
 420  * Enabled only in -O2 compiles, not -Os.
 421  * uclibc itself is usually built without __USE_EXTERN_INLINES,
 422  * remove "&& !defined __OPTIMIZE_SIZE__" part to do otherwise.
 423  */
 424 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
 425     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
 426     && (defined __extern_inline || defined __GNUC_GNU_INLINE__ || defined __GNUC_STDC_INLINE__)
 427 # define __USE_EXTERN_INLINES   1
 428 #endif
 429
 430 #ifdef _LIBC
 431 #  undef _FILE_OFFSET_BITS
 432 #  undef __USE_FILE_OFFSET64
 433 # include <libc-internal.h>
 434 #endif
 435
 436 #endif  /* features.h  */