1POSIXOPTIONS(7) Linux Programmer's Manual POSIXOPTIONS(7)
2
6 posixoptions - optional parts of the POSIX standard
7
9 The POSIX standard (the information below is from POSIX.1-2001)
10 describes a set of behaviors and interfaces for a compliant system.
11 However, many interfaces are optional and there are feature test macros
12 to test the availability of interfaces at compile time, and functions
13 sysconf(3), fpathconf(3), pathconf(3), confstr(3) to do this at run
14 time. From shell scripts one can use getconf(1). For more detail, see
15 sysconf(3).
16 We give the name of the POSIX abbreviation, the option, the name of the
18 sysconf() parameter used to inquire about the option, and possibly a
19 very short description. Much more precise detail can be found in the
20 POSIX standard itself, versions of which can nowadays be accessed
21 freely on the web.
22 ADV - _POSIX_ADVISORY_INFO - _SC_ADVISORY_INFO
24 The following advisory functions are present:
25 posix_fadvise(),
27 posix_fallocate(),
28 posix_memalign(),
29 posix_madvise().
30 AIO - _POSIX_ASYNCHRONOUS_IO - _SC_ASYNCHRONOUS_IO
32 The header <aio.h> is present. The following functions are present:
33 aio_cancel(),
35 aio_error(),
36 aio_fsync(),
37 aio_read(),
38 aio_return(),
39 aio_suspend(),
40 aio_write(),
41 lio_listio().
42 BAR - _POSIX_BARRIERS - _SC_BARRIERS
44 This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS
45 options. The following functions are present:
46 pthread_barrier_destroy(),
48 pthread_barrier_init(),
49 pthread_barrier_wait(),
50 pthread_barrierattr_destroy(),
51 pthread_barrierattr_init().
52 --- - POSIX_CHOWN_RESTRICTED
54 If this option is in effect (as it always is under POSIX.1-2001) then
55 only root may change the owner of a file, and non-root can only set the
56 group of a file to one of the groups it belongs to. This affects the
57 functions chown(), fchown().
58 CS - _POSIX_CLOCK_SELECTION - _SC_CLOCK_SELECTION
60 This option implies the _POSIX_TIMERS option. The following functions
61 are present:
62 pthread_condattr_getclock(),
64 pthread_condattr_setclock(),
65 clock_nanosleep().
66 If CLOCK_REALTIME is changed by the function clock_settime(), then this
68 affects all timers set for an absolute time.
69 CPT - _POSIX_CPUTIME - _SC_CPUTIME
71 The clockID CLOCK_PROCESS_CPUTIME_ID is supported. The initial value
72 of this clock is 0 for each process. This option implies the
73 _POSIX_TIMERS option. The function clock_getcpuclockid() is present.
74 --- - _POSIX_FILE_LOCKING - _SC_FILE_LOCKING
76 This option has been deleted. Not in final XPG6.
77 FSC - _POSIX_FSYNC - _SC_FSYNC
79 The function fsync() is present.
80 IP6 - _POSIX_IPV6 - _SC_IPV6
82 Internet Protocol Version 6 is supported.
83 --- - _POSIX_JOB_CONTROL - _SC_JOB_CONTROL
85 If this option is in effect (as it always is under POSIX.1-2001) then
86 the system implements POSIX-style job control, and the following func‐
87 tions are present:
88 setpgid(),
90 tcdrain(),
91 tcflush(),
92 tcgetpgrp(),
93 tcsendbreak(),
94 tcsetattr(),
95 tcsetpgrp().
96 MF - _POSIX_MAPPED_FILES - _SC_MAPPED_FILES
98 Shared memory is supported. The include file <sys/mman.h> is present.
99 The following functions are present: mmap(), msync(), munmap().
100 ML - _POSIX_MEMLOCK - _SC_MEMLOCK
102 Shared memory can be locked into core. The functions mlockall(),
103 munlockall() are present.
104 MR/MLR - _POSIX_MEMLOCK_RANGE - _SC_MEMLOCK_RANGE
106 More precisely, ranges can be locked into core. The functions mlock(),
107 munlock() are present.
108 MPR - _POSIX_MEMORY_PROTECTION - _SC_MEMORY_PROTECTION
110 The function mprotect() is present.
111 MSG - _POSIX_MESSAGE_PASSING - _SC_MESSAGE_PASSING
113 The include file <mqueue.h> is present. The following functions are
114 present:
115 mq_close(),
117 mq_getattr(),
118 mq_notify(),
119 mq_open(),
120 mq_receive(),
121 mq_send(),
122 mq_setattr(),
123 mq_unlink().
124 MON - _POSIX_MONOTONIC_CLOCK - _SC_MONOTONIC_CLOCK
126 CLOCK_MONOTONIC is supported. This option implies the _POSIX_TIMERS
127 option. Affected functions are
128 aio_suspend(),
130 clock_getres(),
131 clock_gettime(),
132 clock_settime(),
133 timer_create().
134 --- - _POSIX_MULTI_PROCESS - _SC_MULTI_PROCESS
136 This option has been deleted. Not in final XPG6.
137 --- - _POSIX_NO_TRUNC
139 If this option is in effect (as it always is under POSIX.1-2001) then
140 pathname components longer than NAME_MAX are not truncated, but give an
141 error. This property may be dependent on the path prefix of the compo‐
142 nent.
143 PIO - _POSIX_PRIORITIZED_IO - _SC_PRIORITIZED_IO
145 This option says that one can specify priorities for asynchronous I/O.
146 This affects the functions
147 aio_read(),
149 aio_write().
150 PS - _POSIX_PRIORITY_SCHEDULING - _SC_PRIORITY_SCHEDULING
152 The include file <sched.h> is present. The following functions are
153 present:
154 sched_get_priority_max(),
156 sched_get_priority_min(),
157 sched_getparam(),
158 sched_getscheduler(),
159 sched_rr_get_interval(),
160 sched_setparam(),
161 sched_setscheduler(),
162 sched_yield().
163 If also _POSIX_SPAWN is in effect, then the following functions are
165 present:
166 posix_spawnattr_getschedparam(),
168 posix_spawnattr_getschedpolicy(),
169 posix_spawnattr_setschedparam(),
170 posix_spawnattr_setschedpolicy().
171 RS - _POSIX_RAW_SOCKETS
173 Raw sockets are supported. Affected functions are getsockopt(), set‐
174 sockopt().
175 --- - _POSIX_READER_WRITER_LOCKS - _SC_READER_WRITER_LOCKS
177 This option implies the _POSIX_THREADS option. Conversely, under
178 POSIX.1-2001 the _POSIX_THREADS option implies this option.
179 The following functions are present:
180 pthread_rwlock_destroy(),
182 pthread_rwlock_init(),
183 pthread_rwlock_rdlock(),
184 pthread_rwlock_tryrdlock(),
185 pthread_rwlock_trywrlock(),
186 pthread_rwlock_unlock(),
187 pthread_rwlock_wrlock(),
188 pthread_rwlockattr_destroy(),
189 pthread_rwlockattr_init().
190 RTS - _POSIX_REALTIME_SIGNALS - _SC_REALTIME_SIGNALS
192 Realtime signals are supported. The following functions are present:
193 sigqueue(),
195 sigtimedwait(),
196 sigwaitinfo().
197 --- - _POSIX_REGEXP - _SC_REGEXP
199 If this option is in effect (as it always is under POSIX.1-2001) then
200 POSIX regular expressions are supported and the following functions are
201 present:
202 regcomp(),
204 regerror(),
205 regexec(),
206 regfree().
207 --- - _POSIX_SAVED_IDS - _SC_SAVED_IDS
209 If this option is in effect (as it always is under POSIX.1-2001) then a
210 process has a saved set-user-ID and a saved set-group-ID. Affected
211 functions are
212 exec(),
214 kill(),
215 seteuid(),
216 setegid(),
217 setgid(),
218 setuid().
219 SEM - _POSIX_SEMAPHORES - _SC_SEMAPHORES
221 The include file <semaphore.h> is present. The following functions are
222 present:
223 sem_close(),
225 sem_destroy(),
226 sem_getvalue(),
227 sem_init(),
228 sem_open(),
229 sem_post(),
230 sem_trywait(),
231 sem_unlink(),
232 sem_wait().
233 SHM - _POSIX_SHARED_MEMORY_OBJECTS - _SC_SHARED_MEMORY_OBJECTS
235 The following functions are present:
236 mmap(),
238 munmap(),
239 shm_open(),
240 shm_unlink().
241 --- - _POSIX_SHELL - _SC_SHELL
243 If this option is in effect (as it always is under POSIX.1-2001), the
244 function system() is present.
245 SPN - _POSIX_SPAWN - _SC_SPAWN
247 This option describes support for process creation in a context where
248 it is difficult or impossible to use fork(), for example, because no
249 MMU is present. If _POSIX_SPAWN is in effect, then the include file
250 <spawn.h> and the following functions are present:
251 posix_spawn(),
253 posix_spawn_file_actions_addclose(),
254 posix_spawn_file_actions_adddup2(),
255 posix_spawn_file_actions_addopen(),
256 posix_spawn_file_actions_destroy(),
257 posix_spawn_file_actions_init(),
258 posix_spawnattr_destroy(),
259 posix_spawnattr_getsigdefault(),
260 posix_spawnattr_getflags(),
261 posix_spawnattr_getpgroup(),
262 posix_spawnattr_getsigmask(),
263 posix_spawnattr_init(),
264 posix_spawnattr_setsigdefault(),
265 posix_spawnattr_setflags(),
266 posix_spawnattr_setpgroup(),
267 posix_spawnattr_setsigmask(),
268 posix_spawnp().
269 If also _POSIX_PRIORITY_SCHEDULING is in effect, then the following
270 functions are present:
271 posix_spawnattr_getschedparam(),
273 posix_spawnattr_getschedpolicy(),
274 posix_spawnattr_setschedparam(),
275 posix_spawnattr_setschedpolicy().
276 SPI - _POSIX_SPIN_LOCKS - _SC_SPIN_LOCKS
278 This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS
279 options. The following functions are present:
280 pthread_spin_destroy(),
282 pthread_spin_init(),
283 pthread_spin_lock(),
284 pthread_spin_trylock(),
285 pthread_spin_unlock().
286 SS - _POSIX_SPORADIC_SERVER - _SC_SPORADIC_SERVER
288 The scheduling policy SCHED_SPORADIC is supported. This option implies
289 the _POSIX_PRIORITY_SCHEDULING option. Affected functions are
290 sched_setparam(),
292 sched_setscheduler().
293 SIO - _POSIX_SYNCHRONIZED_IO - _SC_SYNCHRONIZED_IO
295 Affected functions are open(), msync(), fsync(), fdatasync().
296 TSA - _POSIX_THREAD_ATTR_STACKADDR - _SC_THREAD_ATTR_STACKADDR
298 Affected functions are
299 pthread_attr_getstack(),
301 pthread_attr_getstackaddr(),
302 pthread_attr_setstack(),
303 pthread_attr_setstackaddr().
304 TSS - _POSIX_THREAD_ATTR_STACKSIZE - _SC_THREAD_ATTR_STACKSIZE
306 Affected functions are
307 pthread_attr_getstack(),
309 pthread_attr_getstacksize(),
310 pthread_attr_setstack(),
311 pthread_attr_setstacksize().
312 TCT - _POSIX_THREAD_CPUTIME - _SC_THREAD_CPUTIME
314 The clockID CLOCK_THREAD_CPUTIME_ID is supported. This option implies
315 the _POSIX_TIMERS option. Affected functions are
316 pthread_getcpuclockid(),
318 clock_getres(),
319 clock_gettime(),
320 clock_settime(),
321 timer_create().
322 TPI - _POSIX_THREAD_PRIO_INHERIT - _SC_THREAD_PRIO_INHERIT
324 Affected functions are
325 pthread_mutexattr_getprotocol(),
327 pthread_mutexattr_setprotocol().
328 TPP - _POSIX_THREAD_PRIO_PROTECT - _SC_THREAD_PRIO_PROTECT
330 Affected functions are
331 pthread_mutex_getprioceiling(),
333 pthread_mutex_setprioceiling(),
334 pthread_mutexattr_getprioceiling(),
335 pthread_mutexattr_getprotocol(),
336 pthread_mutexattr_setprioceiling(),
337 pthread_mutexattr_setprotocol().
338 TPS - _POSIX_THREAD_PRIORITY_SCHEDULING - _SC_THREAD_PRIORITY_SCHEDULING
340 If this option is in effect, the different threads inside a process can
341 run with different priorities and/or different schedulers. Affected
342 functions are
343 pthread_attr_getinheritsched(),
345 pthread_attr_getschedpolicy(),
346 pthread_attr_getscope(),
347 pthread_attr_setinheritsched(),
348 pthread_attr_setschedpolicy(),
349 pthread_attr_setscope(),
350 pthread_getschedparam(),
351 pthread_setschedparam(),
352 pthread_setschedprio().
353 TSH - _POSIX_THREAD_PROCESS_SHARED - _SC_THREAD_PROCESS_SHARED
355 Affected functions are
356 pthread_barrierattr_getpshared(),
358 pthread_barrierattr_setpshared(),
359 pthread_condattr_getpshared(),
360 pthread_condattr_setpshared(),
361 pthread_mutexattr_getpshared(),
362 pthread_mutexattr_setpshared(),
363 pthread_rwlockattr_getpshared(),
364 pthread_rwlockattr_setpshared().
365 TSF - _POSIX_THREAD_SAFE_FUNCTIONS - _SC_THREAD_SAFE_FUNCTIONS
367 Affected functions are
368 readdir_r(),
370 getgrgid_r(),
371 getgrnam_r(),
372 getpwnam_r(),
373 getpwuid_r(),
374 flockfile(),
375 ftrylockfile(),
376 funlockfile(),
377 getc_unlocked(),
378 getchar_unlocked(),
379 putc_unlocked(),
380 putchar_unlocked(),
381 rand_r(),
382 strerror_r(),
383 strtok_r(),
384 asctime_r(),
385 ctime_r(),
386 gmtime_r(),
387 localtime_r().
388 TSP - _POSIX_THREAD_SPORADIC_SERVER - _SC_THREAD_SPORADIC_SERVER
390 This option implies the _POSIX_THREAD_PRIORITY_SCHEDULING option.
391 Affected functions are
392 sched_getparam(),
394 sched_setparam(),
395 sched_setscheduler().
396 THR - _POSIX_THREADS - _SC_THREADS
398 Basic support for POSIX threads is available. The following functions
399 are present:
400 pthread_atfork(),
402 pthread_attr_destroy(),
403 pthread_attr_getdetachstate(),
404 pthread_attr_getschedparam(),
405 pthread_attr_init(),
406 pthread_attr_setdetachstate(),
407 pthread_attr_setschedparam(),
408 pthread_cancel(),
409 pthread_cleanup_push(),
410 pthread_cleanup_pop(),
411 pthread_cond_broadcast(),
412 pthread_cond_destroy(),
413 pthread_cond_init(),
414 pthread_cond_signal(),
415 pthread_cond_timedwait(),
416 pthread_cond_wait(),
417 pthread_condattr_destroy(),
418 pthread_condattr_init(),
419 pthread_create(),
420 pthread_detach(),
421 pthread_equal(),
422 pthread_exit(),
423 pthread_getspecific(),
424 pthread_join(),
425 pthread_key_create(),
426 pthread_key_delete(),
427 pthread_mutex_destroy(),
428 pthread_mutex_init(),
429 pthread_mutex_lock(),
430 pthread_mutex_trylock(),
431 pthread_mutex_unlock(),
432 pthread_mutexattr_destroy(),
433 pthread_mutexattr_init(),
434 pthread_once(),
435 pthread_rwlock_destroy(),
436 pthread_rwlock_init(),
437 pthread_rwlock_rdlock(),
438 pthread_rwlock_tryrdlock(),
439 pthread_rwlock_trywrlock(),
440 pthread_rwlock_unlock(),
441 pthread_rwlock_wrlock(),
442 pthread_rwlockattr_destroy(),
443 pthread_rwlockattr_init(),
444 pthread_self(),
445 pthread_setcancelstate(),
446 pthread_setcanceltype(),
447 pthread_setspecific(),
448 pthread_testcancel().
449 TMO - _POSIX_TIMEOUTS - _SC_TIMEOUTS
451 The following functions are present:
452 mq_timedreceive(),
454 mq_timedsend(),
455 pthread_mutex_timedlock(),
456 pthread_rwlock_timedrdlock(),
457 pthread_rwlock_timedwrlock(),
458 sem_timedwait(),
459 posix_trace_timedgetnext_event().
460 TMR - _POSIX_TIMERS - _SC_TIMERS
462 The following functions are present:
463 clock_getres(),
465 clock_gettime(),
466 clock_settime(),
467 nanosleep(),
468 timer_create(),
469 timer_delete(),
470 timer_gettime(),
471 timer_getoverrun(),
472 timer_settime().
473 TRC - _POSIX_TRACE - _SC_TRACE
475 POSIX tracing is available. The following functions are present:
476 posix_trace_attr_destroy(),
478 posix_trace_attr_getclockres(),
479 posix_trace_attr_getcreatetime(),
480 posix_trace_attr_getgenversion(),
481 posix_trace_attr_getmaxdatasize(),
482 posix_trace_attr_getmaxsystemeventsize(),
483 posix_trace_attr_getmaxusereventsize(),
484 posix_trace_attr_getname(),
485 posix_trace_attr_getstreamfullpolicy(),
486 posix_trace_attr_getstreamsize(),
487 posix_trace_attr_init(),
488 posix_trace_attr_setmaxdatasize(),
489 posix_trace_attr_setname(),
490 posix_trace_attr_setstreamsize(),
491 posix_trace_attr_setstreamfullpolicy(),
492 posix_trace_clear(),
493 posix_trace_create(),
494 posix_trace_event(),
495 posix_trace_eventid_equal(),
496 posix_trace_eventid_get_name(),
497 posix_trace_eventid_open(),
498 posix_trace_eventtypelist_getnext_id(),
499 posix_trace_eventtypelist_rewind(),
500 posix_trace_flush(),
501 posix_trace_get_attr(),
502 posix_trace_get_status(),
503 posix_trace_getnext_event(),
504 posix_trace_shutdown(),
505 posix_trace_start(),
506 posix_trace_stop(),
507 posix_trace_trygetnext_event().
508 TEF - _POSIX_TRACE_EVENT_FILTER - _SC_TRACE_EVENT_FILTER
510 This option implies the _POSIX_TRACE option. The following functions
511 are present:
512 posix_trace_eventset_add(),
514 posix_trace_eventset_del(),
515 posix_trace_eventset_empty(),
516 posix_trace_eventset_fill(),
517 posix_trace_eventset_ismember(),
518 posix_trace_get_filter(),
519 posix_trace_set_filter(),
520 posix_trace_trid_eventid_open().
521 TRI - _POSIX_TRACE_INHERIT - _SC_TRACE_INHERIT
523 Tracing children of the traced process is supported. This option
524 implies the _POSIX_TRACE option. The following functions are present:
525 posix_trace_attr_getinherited(),
527 posix_trace_attr_setinherited().
528 TRL - _POSIX_TRACE_LOG - _SC_TRACE_LOG
530 This option implies the _POSIX_TRACE option. The following functions
531 are present:
532 posix_trace_attr_getlogfullpolicy(),
534 posix_trace_attr_getlogsize(),
535 posix_trace_attr_setlogfullpolicy(),
536 posix_trace_attr_setlogsize(),
537 posix_trace_close(),
538 posix_trace_create_withlog(),
539 posix_trace_open(),
540 posix_trace_rewind().
541 TYM - _POSIX_TYPED_MEMORY_OBJECTS - _SC_TYPED_MEMORY_OBJECT
543 The following functions are present:
544 posix_mem_offset(),
546 posix_typed_mem_get_info(),
547 posix_typed_mem_open().
548 --- - _POSIX_VDISABLE
550 Always present (probably 0). Value to set a changeable special control
551 character to indicate that it is disabled.
552
554 _XOPEN_CRYPT, _XOPEN_LEGACY, _XOPEN_REALTIME, _XOPEN_REALTIME_THREADS,
555 _XOPEN_UNIX.
556
558 sysconf(3), standards(7)
559
561 This page is part of release 3.22 of the Linux man-pages project. A
562 description of the project, and information about reporting bugs, can
563 be found at http://www.kernel.org/doc/man-pages/.
564 2007-12-21 POSIXOPTIONS(7)