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(3) 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 nonroot can set the group
56 of a file only 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
164 present:
165 posix_spawnattr_getschedparam(),
167 posix_spawnattr_getschedpolicy(),
168 posix_spawnattr_setschedparam(),
169 posix_spawnattr_setschedpolicy().
170 RS - _POSIX_RAW_SOCKETS
172 Raw sockets are supported. Affected functions are getsockopt(), set‐
173 sockopt().
174 --- - _POSIX_READER_WRITER_LOCKS - _SC_READER_WRITER_LOCKS
176 This option implies the _POSIX_THREADS option. Conversely, under
177 POSIX.1-2001 the _POSIX_THREADS option implies this option.
178 The following functions are present:
180 pthread_rwlock_destroy(),
181 pthread_rwlock_init(),
182 pthread_rwlock_rdlock(),
183 pthread_rwlock_tryrdlock(),
184 pthread_rwlock_trywrlock(),
185 pthread_rwlock_unlock(),
186 pthread_rwlock_wrlock(),
187 pthread_rwlockattr_destroy(),
188 pthread_rwlockattr_init().
189 RTS - _POSIX_REALTIME_SIGNALS - _SC_REALTIME_SIGNALS
191 Realtime signals are supported. The following functions are present:
192 sigqueue(),
194 sigtimedwait(),
195 sigwaitinfo().
196 --- - _POSIX_REGEXP - _SC_REGEXP
198 If this option is in effect (as it always is under POSIX.1-2001) then
199 POSIX regular expressions are supported and the following functions are
200 present:
201 regcomp(),
203 regerror(),
204 regexec(),
205 regfree().
206 --- - _POSIX_SAVED_IDS - _SC_SAVED_IDS
208 If this option is in effect (as it always is under POSIX.1-2001), then
209 a process has a saved set-user-ID and a saved set-group-ID. Affected
210 functions are
211 exec(),
213 kill(),
214 seteuid(),
215 setegid(),
216 setgid(),
217 setuid().
218 SEM - _POSIX_SEMAPHORES - _SC_SEMAPHORES
220 The include file <semaphore.h> is present. The following functions are
221 present:
222 sem_close(),
224 sem_destroy(),
225 sem_getvalue(),
226 sem_init(),
227 sem_open(),
228 sem_post(),
229 sem_trywait(),
230 sem_unlink(),
231 sem_wait().
232 SHM - _POSIX_SHARED_MEMORY_OBJECTS - _SC_SHARED_MEMORY_OBJECTS
234 The following functions are present:
235 mmap(),
237 munmap(),
238 shm_open(),
239 shm_unlink().
240 --- - _POSIX_SHELL - _SC_SHELL
242 If this option is in effect (as it always is under POSIX.1-2001), the
243 function system() is present.
244 SPN - _POSIX_SPAWN - _SC_SPAWN
246 This option describes support for process creation in a context where
247 it is difficult or impossible to use fork(), for example, because no
248 MMU is present. If _POSIX_SPAWN is in effect, then the include file
249 <spawn.h> and the following functions are present:
250 posix_spawn(),
252 posix_spawn_file_actions_addclose(),
253 posix_spawn_file_actions_adddup2(),
254 posix_spawn_file_actions_addopen(),
255 posix_spawn_file_actions_destroy(),
256 posix_spawn_file_actions_init(),
257 posix_spawnattr_destroy(),
258 posix_spawnattr_getsigdefault(),
259 posix_spawnattr_getflags(),
260 posix_spawnattr_getpgroup(),
261 posix_spawnattr_getsigmask(),
262 posix_spawnattr_init(),
263 posix_spawnattr_setsigdefault(),
264 posix_spawnattr_setflags(),
265 posix_spawnattr_setpgroup(),
266 posix_spawnattr_setsigmask(),
267 posix_spawnp().
268 If also _POSIX_PRIORITY_SCHEDULING is in effect, then the following
269 functions are present:
270 posix_spawnattr_getschedparam(),
272 posix_spawnattr_getschedpolicy(),
273 posix_spawnattr_setschedparam(),
274 posix_spawnattr_setschedpolicy().
275 SPI - _POSIX_SPIN_LOCKS - _SC_SPIN_LOCKS
277 This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS
278 options. The following functions are present:
279 pthread_spin_destroy(),
281 pthread_spin_init(),
282 pthread_spin_lock(),
283 pthread_spin_trylock(),
284 pthread_spin_unlock().
285 SS - _POSIX_SPORADIC_SERVER - _SC_SPORADIC_SERVER
287 The scheduling policy SCHED_SPORADIC is supported. This option implies
288 the _POSIX_PRIORITY_SCHEDULING option. Affected functions are
289 sched_setparam(),
291 sched_setscheduler().
292 SIO - _POSIX_SYNCHRONIZED_IO - _SC_SYNCHRONIZED_IO
294 Affected functions are open(), msync(), fsync(), fdatasync().
295 TSA - _POSIX_THREAD_ATTR_STACKADDR - _SC_THREAD_ATTR_STACKADDR
297 Affected functions are
298 pthread_attr_getstack(),
300 pthread_attr_getstackaddr(),
301 pthread_attr_setstack(),
302 pthread_attr_setstackaddr().
303 TSS - _POSIX_THREAD_ATTR_STACKSIZE - _SC_THREAD_ATTR_STACKSIZE
305 Affected functions are
306 pthread_attr_getstack(),
308 pthread_attr_getstacksize(),
309 pthread_attr_setstack(),
310 pthread_attr_setstacksize().
311 TCT - _POSIX_THREAD_CPUTIME - _SC_THREAD_CPUTIME
313 The clockID CLOCK_THREAD_CPUTIME_ID is supported. This option implies
314 the _POSIX_TIMERS option. Affected functions are
315 pthread_getcpuclockid(),
317 clock_getres(),
318 clock_gettime(),
319 clock_settime(),
320 timer_create().
321 TPI - _POSIX_THREAD_PRIO_INHERIT - _SC_THREAD_PRIO_INHERIT
323 Affected functions are
324 pthread_mutexattr_getprotocol(),
326 pthread_mutexattr_setprotocol().
327 TPP - _POSIX_THREAD_PRIO_PROTECT - _SC_THREAD_PRIO_PROTECT
329 Affected functions are
330 pthread_mutex_getprioceiling(),
332 pthread_mutex_setprioceiling(),
333 pthread_mutexattr_getprioceiling(),
334 pthread_mutexattr_getprotocol(),
335 pthread_mutexattr_setprioceiling(),
336 pthread_mutexattr_setprotocol().
337 TPS - _POSIX_THREAD_PRIORITY_SCHEDULING - _SC_THREAD_PRIORITY_SCHEDULING
339 If this option is in effect, the different threads inside a process can
340 run with different priorities and/or different schedulers. Affected
341 functions are
342 pthread_attr_getinheritsched(),
344 pthread_attr_getschedpolicy(),
345 pthread_attr_getscope(),
346 pthread_attr_setinheritsched(),
347 pthread_attr_setschedpolicy(),
348 pthread_attr_setscope(),
349 pthread_getschedparam(),
350 pthread_setschedparam(),
351 pthread_setschedprio().
352 TSH - _POSIX_THREAD_PROCESS_SHARED - _SC_THREAD_PROCESS_SHARED
354 Affected functions are
355 pthread_barrierattr_getpshared(),
357 pthread_barrierattr_setpshared(),
358 pthread_condattr_getpshared(),
359 pthread_condattr_setpshared(),
360 pthread_mutexattr_getpshared(),
361 pthread_mutexattr_setpshared(),
362 pthread_rwlockattr_getpshared(),
363 pthread_rwlockattr_setpshared().
364 TSF - _POSIX_THREAD_SAFE_FUNCTIONS - _SC_THREAD_SAFE_FUNCTIONS
366 Affected functions are
367 readdir_r(),
369 getgrgid_r(),
370 getgrnam_r(),
371 getpwnam_r(),
372 getpwuid_r(),
373 flockfile(),
374 ftrylockfile(),
375 funlockfile(),
376 getc_unlocked(),
377 getchar_unlocked(),
378 putc_unlocked(),
379 putchar_unlocked(),
380 rand_r(),
381 strerror_r(),
382 strtok_r(),
383 asctime_r(),
384 ctime_r(),
385 gmtime_r(),
386 localtime_r().
387 TSP - _POSIX_THREAD_SPORADIC_SERVER - _SC_THREAD_SPORADIC_SERVER
389 This option implies the _POSIX_THREAD_PRIORITY_SCHEDULING option.
390 Affected functions are
391 sched_getparam(),
393 sched_setparam(),
394 sched_setscheduler().
395 THR - _POSIX_THREADS - _SC_THREADS
397 Basic support for POSIX threads is available. The following functions
398 are present:
399 pthread_atfork(),
401 pthread_attr_destroy(),
402 pthread_attr_getdetachstate(),
403 pthread_attr_getschedparam(),
404 pthread_attr_init(),
405 pthread_attr_setdetachstate(),
406 pthread_attr_setschedparam(),
407 pthread_cancel(),
408 pthread_cleanup_push(),
409 pthread_cleanup_pop(),
410 pthread_cond_broadcast(),
411 pthread_cond_destroy(),
412 pthread_cond_init(),
413 pthread_cond_signal(),
414 pthread_cond_timedwait(),
415 pthread_cond_wait(),
416 pthread_condattr_destroy(),
417 pthread_condattr_init(),
418 pthread_create(),
419 pthread_detach(),
420 pthread_equal(),
421 pthread_exit(),
422 pthread_getspecific(),
423 pthread_join(),
424 pthread_key_create(),
425 pthread_key_delete(),
426 pthread_mutex_destroy(),
427 pthread_mutex_init(),
428 pthread_mutex_lock(),
429 pthread_mutex_trylock(),
430 pthread_mutex_unlock(),
431 pthread_mutexattr_destroy(),
432 pthread_mutexattr_init(),
433 pthread_once(),
434 pthread_rwlock_destroy(),
435 pthread_rwlock_init(),
436 pthread_rwlock_rdlock(),
437 pthread_rwlock_tryrdlock(),
438 pthread_rwlock_trywrlock(),
439 pthread_rwlock_unlock(),
440 pthread_rwlock_wrlock(),
441 pthread_rwlockattr_destroy(),
442 pthread_rwlockattr_init(),
443 pthread_self(),
444 pthread_setcancelstate(),
445 pthread_setcanceltype(),
446 pthread_setspecific(),
447 pthread_testcancel().
448 TMO - _POSIX_TIMEOUTS - _SC_TIMEOUTS
450 The following functions are present:
451 mq_timedreceive(),
453 mq_timedsend(),
454 pthread_mutex_timedlock(),
455 pthread_rwlock_timedrdlock(),
456 pthread_rwlock_timedwrlock(),
457 sem_timedwait(),
458 posix_trace_timedgetnext_event().
459 TMR - _POSIX_TIMERS - _SC_TIMERS
461 The following functions are present:
462 clock_getres(),
464 clock_gettime(),
465 clock_settime(),
466 nanosleep(),
467 timer_create(),
468 timer_delete(),
469 timer_gettime(),
470 timer_getoverrun(),
471 timer_settime().
472 TRC - _POSIX_TRACE - _SC_TRACE
474 POSIX tracing is available. The following functions are present:
475 posix_trace_attr_destroy(),
477 posix_trace_attr_getclockres(),
478 posix_trace_attr_getcreatetime(),
479 posix_trace_attr_getgenversion(),
480 posix_trace_attr_getmaxdatasize(),
481 posix_trace_attr_getmaxsystemeventsize(),
482 posix_trace_attr_getmaxusereventsize(),
483 posix_trace_attr_getname(),
484 posix_trace_attr_getstreamfullpolicy(),
485 posix_trace_attr_getstreamsize(),
486 posix_trace_attr_init(),
487 posix_trace_attr_setmaxdatasize(),
488 posix_trace_attr_setname(),
489 posix_trace_attr_setstreamsize(),
490 posix_trace_attr_setstreamfullpolicy(),
491 posix_trace_clear(),
492 posix_trace_create(),
493 posix_trace_event(),
494 posix_trace_eventid_equal(),
495 posix_trace_eventid_get_name(),
496 posix_trace_eventid_open(),
497 posix_trace_eventtypelist_getnext_id(),
498 posix_trace_eventtypelist_rewind(),
499 posix_trace_flush(),
500 posix_trace_get_attr(),
501 posix_trace_get_status(),
502 posix_trace_getnext_event(),
503 posix_trace_shutdown(),
504 posix_trace_start(),
505 posix_trace_stop(),
506 posix_trace_trygetnext_event().
507 TEF - _POSIX_TRACE_EVENT_FILTER - _SC_TRACE_EVENT_FILTER
509 This option implies the _POSIX_TRACE option. The following functions
510 are present:
511 posix_trace_eventset_add(),
513 posix_trace_eventset_del(),
514 posix_trace_eventset_empty(),
515 posix_trace_eventset_fill(),
516 posix_trace_eventset_ismember(),
517 posix_trace_get_filter(),
518 posix_trace_set_filter(),
519 posix_trace_trid_eventid_open().
520 TRI - _POSIX_TRACE_INHERIT - _SC_TRACE_INHERIT
522 Tracing children of the traced process is supported. This option
523 implies the _POSIX_TRACE option. The following functions are present:
524 posix_trace_attr_getinherited(),
526 posix_trace_attr_setinherited().
527 TRL - _POSIX_TRACE_LOG - _SC_TRACE_LOG
529 This option implies the _POSIX_TRACE option. The following functions
530 are present:
531 posix_trace_attr_getlogfullpolicy(),
533 posix_trace_attr_getlogsize(),
534 posix_trace_attr_setlogfullpolicy(),
535 posix_trace_attr_setlogsize(),
536 posix_trace_close(),
537 posix_trace_create_withlog(),
538 posix_trace_open(),
539 posix_trace_rewind().
540 TYM - _POSIX_TYPED_MEMORY_OBJECTS - _SC_TYPED_MEMORY_OBJECT
542 The following functions are present:
543 posix_mem_offset(),
545 posix_typed_mem_get_info(),
546 posix_typed_mem_open().
547 --- - _POSIX_VDISABLE
549 Always present (probably 0). Value to set a changeable special control
550 character to indicate that it is disabled.
551
553 _XOPEN_CRYPT, _XOPEN_LEGACY, _XOPEN_REALTIME, _XOPEN_REALTIME_THREADS,
554 _XOPEN_UNIX.
555
557 sysconf(3), standards(7)
558
560 This page is part of release 4.15 of the Linux man-pages project. A
561 description of the project, information about reporting bugs, and the
562 latest version of this page, can be found at
563 https://www.kernel.org/doc/man-pages/.
564 2007-12-21 POSIXOPTIONS(7)