features.h 15 KB

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  1. /* Copyright (C) 1991,92,93,95,96,97,98,99,2000,2001 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, write to the Free
  13. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  14. 02111-1307 USA. */
  15. #ifndef _FEATURES_H
  16. #define _FEATURES_H 1
  17. /* For uClibc, always optimize for size -- this should disable
  18. * a lot of expensive inlining... */
  19. #define __OPTIMIZE_SIZE__ 1
  20. /* These are defined by the user (or the compiler)
  21. to specify the desired environment:
  22. __STRICT_ANSI__ ISO Standard C.
  23. _ISOC99_SOURCE Extensions to ISO C89 from ISO C99.
  24. _POSIX_SOURCE IEEE Std 1003.1.
  25. _POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
  26. if >=199309L, add IEEE Std 1003.1b-1993;
  27. if >=199506L, add IEEE Std 1003.1c-1995
  28. _XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if
  29. Single Unix conformance is wanted, to 600 for the
  30. upcoming sixth revision.
  31. _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  32. _LARGEFILE_SOURCE Some more functions for correct standard I/O.
  33. _LARGEFILE64_SOURCE Additional functionality from LFS for large files.
  34. _FILE_OFFSET_BITS=N Select default filesystem interface.
  35. _BSD_SOURCE ISO C, POSIX, and 4.3BSD things.
  36. _SVID_SOURCE ISO C, POSIX, and SVID things.
  37. _GNU_SOURCE All of the above, plus GNU extensions.
  38. _REENTRANT Select additionally reentrant object.
  39. _THREAD_SAFE Same as _REENTRANT, often used by other systems.
  40. The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  41. If none of these are defined, the default is to have _SVID_SOURCE,
  42. _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
  43. 199506L. If more than one of these are defined, they accumulate.
  44. For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  45. together give you ISO C, 1003.1, and 1003.2, but nothing else.
  46. These are defined by this file and are used by the
  47. header files to decide what to declare or define:
  48. __USE_ISOC99 Define ISO C99 things.
  49. __USE_POSIX Define IEEE Std 1003.1 things.
  50. __USE_POSIX2 Define IEEE Std 1003.2 things.
  51. __USE_POSIX199309 Define IEEE Std 1003.1, and .1b things.
  52. __USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things.
  53. __USE_XOPEN Define XPG things.
  54. __USE_XOPEN_EXTENDED Define X/Open Unix things.
  55. __USE_UNIX98 Define Single Unix V2 things.
  56. __USE_XOPEN2K Define XPG6 things.
  57. __USE_LARGEFILE Define correct standard I/O things.
  58. __USE_LARGEFILE64 Define LFS things with separate names.
  59. __USE_FILE_OFFSET64 Define 64bit interface as default.
  60. __USE_BSD Define 4.3BSD things.
  61. __USE_SVID Define SVID things.
  62. __USE_MISC Define things common to BSD and System V Unix.
  63. __USE_GNU Define GNU extensions.
  64. __USE_REENTRANT Define reentrant/thread-safe *_r functions.
  65. __FAVOR_BSD Favor 4.3BSD things in cases of conflict.
  66. The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  67. defined by this file unconditionally. `__GNU_LIBRARY__' is provided
  68. only for compatibility. All new code should use the other symbols
  69. to test for features.
  70. All macros listed above as possibly being defined by this file are
  71. explicitly undefined if they are not explicitly defined.
  72. Feature-test macros that are not defined by the user or compiler
  73. but are implied by the other feature-test macros defined (or by the
  74. lack of any definitions) are defined by the file. */
  75. /* Undefine everything, so we get a clean slate. */
  76. #undef __USE_ISOC99
  77. #undef __USE_POSIX
  78. #undef __USE_POSIX2
  79. #undef __USE_POSIX199309
  80. #undef __USE_POSIX199506
  81. #undef __USE_XOPEN
  82. #undef __USE_XOPEN_EXTENDED
  83. #undef __USE_UNIX98
  84. #undef __USE_XOPEN2K
  85. #undef __USE_LARGEFILE
  86. #undef __USE_LARGEFILE64
  87. #undef __USE_FILE_OFFSET64
  88. #undef __USE_BSD
  89. #undef __USE_SVID
  90. #undef __USE_MISC
  91. #undef __USE_GNU
  92. #undef __USE_REENTRANT
  93. #undef __FAVOR_BSD
  94. #undef __KERNEL_STRICT_NAMES
  95. /* Suppress kernel-name space pollution unless user expressedly asks
  96. for it. */
  97. #ifndef _LOOSE_KERNEL_NAMES
  98. # define __KERNEL_STRICT_NAMES
  99. #endif
  100. /* Always use ISO C things. */
  101. #define __USE_ANSI 1
  102. /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX. */
  103. #if defined _BSD_SOURCE && \
  104. !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
  105. defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
  106. defined _GNU_SOURCE || defined _SVID_SOURCE)
  107. # define __FAVOR_BSD 1
  108. #endif
  109. /* If _GNU_SOURCE was defined by the user, turn on all the other features. */
  110. #ifdef _GNU_SOURCE
  111. # undef _ISOC99_SOURCE
  112. # define _ISOC99_SOURCE 1
  113. # undef _POSIX_SOURCE
  114. # define _POSIX_SOURCE 1
  115. # undef _POSIX_C_SOURCE
  116. # define _POSIX_C_SOURCE 199506L
  117. # undef _XOPEN_SOURCE
  118. # define _XOPEN_SOURCE 600
  119. # undef _XOPEN_SOURCE_EXTENDED
  120. # define _XOPEN_SOURCE_EXTENDED 1
  121. # undef _LARGEFILE64_SOURCE
  122. # define _LARGEFILE64_SOURCE 1
  123. # undef _BSD_SOURCE
  124. # define _BSD_SOURCE 1
  125. # undef _SVID_SOURCE
  126. # define _SVID_SOURCE 1
  127. #endif
  128. /* If nothing (other than _GNU_SOURCE) is defined,
  129. define _BSD_SOURCE and _SVID_SOURCE. */
  130. #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
  131. !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
  132. !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
  133. !defined _BSD_SOURCE && !defined _SVID_SOURCE)
  134. # define _BSD_SOURCE 1
  135. # define _SVID_SOURCE 1
  136. #endif
  137. /* This is to enable the ISO C99 extension. Also recognize the old macro
  138. which was used prior to the standard acceptance. This macro will
  139. eventually go away and the features enabled by default once the ISO C99
  140. standard is widely adopted. */
  141. #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
  142. || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
  143. # define __USE_ISOC99 1
  144. #endif
  145. /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
  146. (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined). */
  147. #if (!defined __STRICT_ANSI__ && !defined _POSIX_SOURCE && \
  148. !defined _POSIX_C_SOURCE)
  149. # define _POSIX_SOURCE 1
  150. # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
  151. # define _POSIX_C_SOURCE 2
  152. # else
  153. # define _POSIX_C_SOURCE 199506L
  154. # endif
  155. #endif
  156. #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
  157. # define __USE_POSIX 1
  158. #endif
  159. #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
  160. # define __USE_POSIX2 1
  161. #endif
  162. #if (_POSIX_C_SOURCE - 0) >= 199309L
  163. # define __USE_POSIX199309 1
  164. #endif
  165. #if (_POSIX_C_SOURCE - 0) >= 199506L
  166. # define __USE_POSIX199506 1
  167. #endif
  168. #ifdef _XOPEN_SOURCE
  169. # define __USE_XOPEN 1
  170. # if (_XOPEN_SOURCE - 0) >= 500
  171. # define __USE_XOPEN_EXTENDED 1
  172. # define __USE_UNIX98 1
  173. # undef _LARGEFILE_SOURCE
  174. # define _LARGEFILE_SOURCE 1
  175. # if (_XOPEN_SOURCE - 0) >= 600
  176. # define __USE_XOPEN2K 1
  177. # undef __USE_ISOC99
  178. # define __USE_ISOC99 1
  179. # endif
  180. # else
  181. # ifdef _XOPEN_SOURCE_EXTENDED
  182. # define __USE_XOPEN_EXTENDED 1
  183. # endif
  184. # endif
  185. #endif
  186. #ifdef _LARGEFILE_SOURCE
  187. # define __USE_LARGEFILE 1
  188. #endif
  189. #ifdef _LARGEFILE64_SOURCE
  190. # define __USE_LARGEFILE64 1
  191. #endif
  192. #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
  193. # define __USE_FILE_OFFSET64 1
  194. #endif
  195. #if defined _BSD_SOURCE || defined _SVID_SOURCE
  196. # define __USE_MISC 1
  197. #endif
  198. #ifdef _BSD_SOURCE
  199. # define __USE_BSD 1
  200. #endif
  201. #ifdef _SVID_SOURCE
  202. # define __USE_SVID 1
  203. #endif
  204. #ifdef _GNU_SOURCE
  205. # define __USE_GNU 1
  206. #endif
  207. #if defined _REENTRANT || defined _THREAD_SAFE
  208. # define __USE_REENTRANT 1
  209. #endif
  210. /* We do support the IEC 559 math functionality, real and complex. */
  211. #define __STDC_IEC_559__ 1
  212. #define __STDC_IEC_559_COMPLEX__ 1
  213. /* wchar_t uses ISO 10646-1 (2nd ed., published 2000-09-15) / Unicode 3.0. */
  214. #define __STDC_ISO_10646__ 200009L
  215. /* This macro indicates that the installed library is uClibc. Use
  216. * __UCLIBC_MAJOR__ and __UCLIBC_MINOR__ to test for the features in
  217. * specific releases. */
  218. #define __UCLIBC__ 1
  219. /* Major and minor version number of the uClibc library package are
  220. * can be used to test for features in specific uClibc releases.
  221. *
  222. * Now included from bits/uClibc_config.h */
  223. #if 0
  224. /* For uClibc release 0.9.12, these numbers would be: */
  225. #define __UCLIBC_MAJOR__ 0
  226. #define __UCLIBC_MINOR__ 9
  227. #define __UCLIBC_SUBLEVEL__ 12
  228. #endif
  229. /* There is an unwholesomely huge amount of code out there that depends on the
  230. * presence of GNU libc header files. We have GNU libc header files. So here
  231. * we commit a horrible sin. At this point, we _lie_ and claim to be GNU libc
  232. * to make things like /usr/include/linux/socket.h and lots of apps work as
  233. * their developers intended. This is IMHO, pardonable, since these defines
  234. * are not really intended to check for the presence of a particular library,
  235. * but rather are used to define an _interface_. */
  236. #if !defined __FORCE_NOGLIBC && (!defined _LIBC || defined __FORCE_GLIBC)
  237. # define __GNU_LIBRARY__ 6
  238. # define __GLIBC__ 2
  239. # define __GLIBC_MINOR__ 2
  240. #endif
  241. /* Convenience macros to test the versions of glibc and gcc.
  242. Use them like this:
  243. #if __GNUC_PREREQ (2,8)
  244. ... code requiring gcc 2.8 or later ...
  245. #endif
  246. Note - they won't work for gcc1 or glibc1, since the _MINOR macros
  247. were not defined then. */
  248. #if defined __GNUC__ && defined __GNUC_MINOR__
  249. # define __GNUC_PREREQ(maj, min) \
  250. ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  251. #else
  252. # define __GNUC_PREREQ(maj, min) 0
  253. #endif
  254. #define __GLIBC_PREREQ(maj, min) \
  255. ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
  256. /* This is here only because every header file already includes this one. */
  257. #ifndef __ASSEMBLER__
  258. #ifndef _SYS_CDEFS_H
  259. # include <sys/cdefs.h>
  260. #endif
  261. /* If we don't have __REDIRECT, prototypes will be missing if
  262. __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
  263. # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
  264. # define __USE_LARGEFILE 1
  265. # define __USE_LARGEFILE64 1
  266. # endif
  267. #endif /* !ASSEMBLER */
  268. /* Decide whether we can define 'extern inline' functions in headers. */
  269. #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
  270. && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__
  271. # define __USE_EXTERN_INLINES 1
  272. #endif
  273. /* This is here only because every header file already includes this one. */
  274. #if 0
  275. /*#ifndef _LIBC*/
  276. /* Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
  277. <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
  278. which will always return failure (and set errno to ENOSYS).
  279. We avoid including <gnu/stubs.h> when compiling the C library itself to
  280. avoid a dependency loop. stubs.h depends on every object file. If
  281. this #include were done for the library source code, then every object
  282. file would depend on stubs.h. */
  283. # include <gnu/stubs.h>
  284. #endif
  285. /* Load up the current set of uClibc supported features */
  286. #define __need_uClibc_config_h
  287. #include <bits/uClibc_config.h>
  288. #undef __need_uClibc_config_h
  289. /* Make sure users large file options agree with uClibc's configuration. */
  290. #ifndef __UCLIBC_HAS_LFS__
  291. /* If uClibc was built without large file support, output an error if
  292. * and 64-bit file offsets were requested, output an error.
  293. * NOTE: This is probably incorrect on a 64-bit arch... */
  294. #ifdef __USE_FILE_OFFSET64
  295. #error It appears you have defined _FILE_OFFSET_BITS=64. Unfortunately, \
  296. uClibc was built without large file support enabled.
  297. #endif
  298. /* If uClibc was built without large file support and _LARGEFILE64_SOURCE
  299. * is defined, undefine it. */
  300. #if defined(_LARGEFILE64_SOURCE)
  301. #undef _LARGEFILE64_SOURCE
  302. #undef __USE_LARGEFILE64
  303. #endif
  304. /* If we're actually building uClibc with large file support,
  305. * define __USE_LARGEFILE64 and __USE_LARGEFILE. */
  306. #elif defined(_LIBC)
  307. #undef _LARGEFILE_SOURCE
  308. #undef _LARGEFILE64_SOURCE
  309. #undef _FILE_OFFSET_BITS
  310. #undef __USE_LARGEFILE
  311. #undef __USE_LARGEFILE64
  312. #undef __USE_FILE_OFFSET64
  313. #define _LARGEFILE_SOURCE 1
  314. #define _LARGEFILE64_SOURCE 1
  315. #define __USE_LARGEFILE 1
  316. #define __USE_LARGEFILE64 1
  317. #endif
  318. /* Some nice features only work properly with ELF */
  319. #if defined _LIBC
  320. #if defined __HAVE_ELF__
  321. /* Define ALIASNAME as a weak alias for NAME. */
  322. # define weak_alias(name, aliasname) _weak_alias (name, aliasname)
  323. # define _weak_alias(name, aliasname) \
  324. extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
  325. /* Define ALIASNAME as a strong alias for NAME. */
  326. # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
  327. # define _strong_alias(name, aliasname) \
  328. extern __typeof (name) aliasname __attribute__ ((alias (#name)));
  329. /* This comes between the return type and function name in
  330. * a function definition to make that definition weak. */
  331. # define weak_function __attribute__ ((weak))
  332. # define weak_const_function __attribute__ ((weak, __const__))
  333. /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
  334. * section attributes on what looks like a comment to the assembler. */
  335. # define link_warning(symbol, msg) \
  336. asm (".section " ".gnu.warning." #symbol "\n\t.previous"); \
  337. static const char __evoke_link_warning_##symbol[] \
  338. __attribute__ ((unused, section (".gnu.warning." #symbol "\n\t#"))) = msg;
  339. #else /* !defined __HAVE_ELF__ */
  340. # define strong_alias(name, aliasname) _strong_alias (name, aliasname)
  341. # define weak_alias(name, aliasname) _strong_alias (name, aliasname)
  342. # define _strong_alias(name, aliasname) \
  343. __asm__(".global " __C_SYMBOL_PREFIX__ #aliasname "\n" \
  344. ".set " __C_SYMBOL_PREFIX__ #aliasname "," __C_SYMBOL_PREFIX__ #name);
  345. # define link_warning(symbol, msg) \
  346. asm (".stabs \"" msg "\",30,0,0,0\n\t" \
  347. ".stabs \"" #symbol "\",1,0,0,0\n");
  348. #endif
  349. #ifndef weak_function
  350. /* If we do not have the __attribute__ ((weak)) syntax, there is no way we
  351. can define functions as weak symbols. The compiler will emit a `.globl'
  352. directive for the function symbol, and a `.weak' directive in addition
  353. will produce an error from the assembler. */
  354. # define weak_function /* empty */
  355. # define weak_const_function /* empty */
  356. #endif
  357. /* On some platforms we can make internal function calls (i.e., calls of
  358. functions not exported) a bit faster by using a different calling
  359. convention. */
  360. #ifndef internal_function
  361. # define internal_function /* empty */
  362. #endif
  363. /* Prepare for the case that `__builtin_expect' is not available. */
  364. #if __GNUC__ == 2 && __GNUC_MINOR__ < 96
  365. #define __builtin_expect(x, expected_value) (x)
  366. #endif
  367. #ifndef likely
  368. # define likely(x) __builtin_expect((!!(x)),1)
  369. #endif
  370. #ifndef unlikely
  371. # define unlikely(x) __builtin_expect((!!(x)),0)
  372. #endif
  373. /* --- this is added to integrate linuxthreads */
  374. #define __USE_UNIX98 1
  375. #endif /* _LIBC only stuff */
  376. #ifndef __linux__
  377. # define __linux__ 1
  378. #endif
  379. #endif /* features.h */