posixoptions

The following advisory functions are present:

posix_fadvise()
posix_fallocate()
posix_memalign()
posix_madvise()

The header <aio.h> is present. The following functions are present:

aio_cancel()
aio_error()
aio_fsync()
aio_read()
aio_return()
aio_suspend()
aio_write()
lio_listio()

This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS options. The following functions are present:

pthread_barrier_destroy()
pthread_barrier_init()
pthread_barrier_wait()
pthread_barrierattr_destroy()
pthread_barrierattr_init()

If this option is in effect (as it always is under POSIX.1-2001), then only root may change the owner of a file, and nonroot can set the group of a file only to one of the groups it belongs to. This affects the following functions

chown()
fchown()

This option implies the _POSIX_TIMERS option. The following functions are present:

pthread_condattr_getclock()
pthread_condattr_setclock()
clock_nanosleep()

If CLOCK_REALTIME is changed by the function clock_settime(), then this affects all timers set for an absolute time.

The CLOCK_PROCESS_CPUTIME_ID clock ID is supported. The initial value of this clock is 0 for each process. This option implies the _POSIX_TIMERS option. The function clock_getcpuclockid() is present.

This option has been deleted. Not in final XPG6.

The function fsync() is present.

Internet Protocol Version 6 is supported.

If this option is in effect (as it always is under POSIX.1-2001), then the system implements POSIX-style job control, and the following functions are present:

setpgid()
tcdrain()
tcflush()
tcgetpgrp()
tcsendbreak()
tcsetattr()
tcsetpgrp()

Shared memory is supported. The include file <sys/mman.h> is present. The following functions are present:

mmap()
msync()
munmap()

Shared memory can be locked into core. The following functions are present:

mlockall()
munlockall()

More precisely, ranges can be locked into core. The following functions are present:

mlock()
munlock()

The function mprotect() is present.

The include file <mqueue.h> is present. The following functions are present:

mq_close()
mq_getattr()
mq_notify()
mq_open()
mq_receive()
mq_send()
mq_setattr()
mq_unlink()

CLOCK_MONOTONIC is supported. This option implies the _POSIX_TIMERS option. The following functions are affected:

aio_suspend()
clock_getres()
clock_gettime()
clock_settime()
timer_create()

This option has been deleted. Not in final XPG6.

If this option is in effect (as it always is under POSIX.1-2001), then pathname components longer than NAME_MAX are not truncated, but give an error. This property may be dependent on the path prefix of the component.

This option says that one can specify priorities for asynchronous I/O. This affects the functions

aio_read()
aio_write()

The include file <sched.h> is present. The following functions are present:

sched_get_priority_max()
sched_get_priority_min()
sched_getparam()
sched_getscheduler()
sched_rr_get_interval()
sched_setparam()
sched_setscheduler()
sched_yield()

If also _POSIX_SPAWN is in effect, then the following functions are present:

posix_spawnattr_getschedparam()
posix_spawnattr_getschedpolicy()
posix_spawnattr_setschedparam()
posix_spawnattr_setschedpolicy()

Raw sockets are supported. The following functions are affected:

getsockopt()
setsockopt()

This option implies the _POSIX_THREADS option. Conversely, under POSIX.1-2001 the _POSIX_THREADS option implies this option.

The following functions are present:

pthread_rwlock_destroy()
pthread_rwlock_init()
pthread_rwlock_rdlock()
pthread_rwlock_tryrdlock()
pthread_rwlock_trywrlock()
pthread_rwlock_unlock()
pthread_rwlock_wrlock()
pthread_rwlockattr_destroy()
pthread_rwlockattr_init()

Realtime signals are supported. The following functions are present:

sigqueue()
sigtimedwait()
sigwaitinfo()

If this option is in effect (as it always is under POSIX.1-2001), then POSIX regular expressions are supported and the following functions are present:

regcomp()
regerror()
regexec()
regfree()

If this option is in effect (as it always is under POSIX.1-2001), then a process has a saved set-user-ID and a saved set-group-ID. The following functions are affected:

exec()
kill()
seteuid()
setegid()
setgid()
setuid()

The include file <semaphore.h> is present. The following functions are present:

sem_close()
sem_destroy()
sem_getvalue()
sem_init()
sem_open()
sem_post()
sem_trywait()
sem_unlink()
sem_wait()

The following functions are present:

mmap()
munmap()
shm_open()
shm_unlink()

If this option is in effect (as it always is under POSIX.1-2001), the function system() is present.

This option describes support for process creation in a context where it is difficult or impossible to use fork(), for example, because no MMU is present.

If _POSIX_SPAWN is in effect, then the include file <spawn.h> and the following functions are present:

posix_spawn()
posix_spawn_file_actions_addclose()
posix_spawn_file_actions_adddup2()
posix_spawn_file_actions_addopen()
posix_spawn_file_actions_destroy()
posix_spawn_file_actions_init()
posix_spawnattr_destroy()
posix_spawnattr_getsigdefault()
posix_spawnattr_getflags()
posix_spawnattr_getpgroup()
posix_spawnattr_getsigmask()
posix_spawnattr_init()
posix_spawnattr_setsigdefault()
posix_spawnattr_setflags()
posix_spawnattr_setpgroup()
posix_spawnattr_setsigmask()
posix_spawnp()

If also _POSIX_PRIORITY_SCHEDULING is in effect, then the following functions are present:

posix_spawnattr_getschedparam()
posix_spawnattr_getschedpolicy()
posix_spawnattr_setschedparam()
posix_spawnattr_setschedpolicy()

This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS options. The following functions are present:

pthread_spin_destroy()
pthread_spin_init()
pthread_spin_lock()
pthread_spin_trylock()
pthread_spin_unlock()

The scheduling policy SCHED_SPORADIC is supported. This option implies the _POSIX_PRIORITY_SCHEDULING option. The following functions are affected:

sched_setparam()
sched_setscheduler()

The following functions are affected:

open()
msync()
fsync()
fdatasync()

The following functions are affected:

pthread_attr_getstack()
pthread_attr_getstackaddr()
pthread_attr_setstack()
pthread_attr_setstackaddr()

The following functions are affected:

pthread_attr_getstack()
pthread_attr_getstacksize()
pthread_attr_setstack()
pthread_attr_setstacksize()

The clockID CLOCK_THREAD_CPUTIME_ID is supported. This option implies the _POSIX_TIMERS option. The following functions are affected:

pthread_getcpuclockid()
clock_getres()
clock_gettime()
clock_settime()
timer_create()

The following functions are affected:

pthread_mutexattr_getprotocol()
pthread_mutexattr_setprotocol()

The following functions are affected:

pthread_mutex_getprioceiling()
pthread_mutex_setprioceiling()
pthread_mutexattr_getprioceiling()
pthread_mutexattr_getprotocol()
pthread_mutexattr_setprioceiling()
pthread_mutexattr_setprotocol()

If this option is in effect, the different threads inside a process can run with different priorities and/or different schedulers. The following functions are affected:

pthread_attr_getinheritsched()
pthread_attr_getschedpolicy()
pthread_attr_getscope()
pthread_attr_setinheritsched()
pthread_attr_setschedpolicy()
pthread_attr_setscope()
pthread_getschedparam()
pthread_setschedparam()
pthread_setschedprio()

The following functions are affected:

pthread_barrierattr_getpshared()
pthread_barrierattr_setpshared()
pthread_condattr_getpshared()
pthread_condattr_setpshared()
pthread_mutexattr_getpshared()
pthread_mutexattr_setpshared()
pthread_rwlockattr_getpshared()
pthread_rwlockattr_setpshared()

The following functions are affected:

readdir_r()
getgrgid_r()
getgrnam_r()
getpwnam_r()
getpwuid_r()
flockfile()
ftrylockfile()
funlockfile()
getc_unlocked()
getchar_unlocked()
putc_unlocked()
putchar_unlocked()
rand_r()
strerror_r()
strtok_r()
asctime_r()
ctime_r()
gmtime_r()
localtime_r()

This option implies the _POSIX_THREAD_PRIORITY_SCHEDULING option. The following functions are affected:

sched_getparam()
sched_setparam()
sched_setscheduler()

Basic support for POSIX threads is available. The following functions are present:

pthread_atfork()
pthread_attr_destroy()
pthread_attr_getdetachstate()
pthread_attr_getschedparam()
pthread_attr_init()
pthread_attr_setdetachstate()
pthread_attr_setschedparam()
pthread_cancel()
pthread_cleanup_push()
pthread_cleanup_pop()
pthread_cond_broadcast()
pthread_cond_destroy()
pthread_cond_init()
pthread_cond_signal()
pthread_cond_timedwait()
pthread_cond_wait()
pthread_condattr_destroy()
pthread_condattr_init()
pthread_create()
pthread_detach()
pthread_equal()
pthread_exit()
pthread_getspecific()
pthread_join()
pthread_key_create()
pthread_key_delete()
pthread_mutex_destroy()
pthread_mutex_init()
pthread_mutex_lock()
pthread_mutex_trylock()
pthread_mutex_unlock()
pthread_mutexattr_destroy()
pthread_mutexattr_init()
pthread_once()
pthread_rwlock_destroy()
pthread_rwlock_init()
pthread_rwlock_rdlock()
pthread_rwlock_tryrdlock()
pthread_rwlock_trywrlock()
pthread_rwlock_unlock()
pthread_rwlock_wrlock()
pthread_rwlockattr_destroy()
pthread_rwlockattr_init()
pthread_self()
pthread_setcancelstate()
pthread_setcanceltype()
pthread_setspecific()
pthread_testcancel()

The following functions are present:

mq_timedreceive()
mq_timedsend()
pthread_mutex_timedlock()
pthread_rwlock_timedrdlock()
pthread_rwlock_timedwrlock()
sem_timedwait()
posix_trace_timedgetnext_event()

The following functions are present:

clock_getres()
clock_gettime()
clock_settime()
nanosleep()
timer_create()
timer_delete()
timer_gettime()
timer_getoverrun()
timer_settime()

POSIX tracing is available. The following functions are present:

posix_trace_attr_destroy()
posix_trace_attr_getclockres()
posix_trace_attr_getcreatetime()
posix_trace_attr_getgenversion()
posix_trace_attr_getmaxdatasize()
posix_trace_attr_getmaxsystemeventsize()
posix_trace_attr_getmaxusereventsize()
posix_trace_attr_getname()
posix_trace_attr_getstreamfullpolicy()
posix_trace_attr_getstreamsize()
posix_trace_attr_init()
posix_trace_attr_setmaxdatasize()
posix_trace_attr_setname()
posix_trace_attr_setstreamsize()
posix_trace_attr_setstreamfullpolicy()
posix_trace_clear()
posix_trace_create()
posix_trace_event()
posix_trace_eventid_equal()
posix_trace_eventid_get_name()
posix_trace_eventid_open()
posix_trace_eventtypelist_getnext_id()
posix_trace_eventtypelist_rewind()
posix_trace_flush()
posix_trace_get_attr()
posix_trace_get_status()
posix_trace_getnext_event()
posix_trace_shutdown()
posix_trace_start()
posix_trace_stop()
posix_trace_trygetnext_event()

This option implies the _POSIX_TRACE option. The following functions are present:

posix_trace_eventset_add()
posix_trace_eventset_del()
posix_trace_eventset_empty()
posix_trace_eventset_fill()
posix_trace_eventset_ismember()
posix_trace_get_filter()
posix_trace_set_filter()
posix_trace_trid_eventid_open()

Tracing children of the traced process is supported. This option implies the _POSIX_TRACE option. The following functions are present:

posix_trace_attr_getinherited()
posix_trace_attr_setinherited()

This option implies the _POSIX_TRACE option. The following functions are present:

posix_trace_attr_getlogfullpolicy()
posix_trace_attr_getlogsize()
posix_trace_attr_setlogfullpolicy()
posix_trace_attr_setlogsize()
posix_trace_close()
posix_trace_create_withlog()
posix_trace_open()
posix_trace_rewind()

The following functions are present:

posix_mem_offset()
posix_typed_mem_get_info()
posix_typed_mem_open()

Always present (probably 0). Value to set a changeable special control character to indicate that it is disabled.

The following functions are present:

crypt()
encrypt()
setkey()

This option implies the following options:

_POSIX_ASYNCHRONOUS_IO==200112L

_POSIX_FSYNC

_POSIX_MAPPED_FILES

_POSIX_MEMLOCK==200112L

_POSIX_MEMLOCK_RANGE==200112L

_POSIX_MEMORY_PROTECTION

_POSIX_MESSAGE_PASSING==200112L

_POSIX_PRIORITIZED_IO

_POSIX_PRIORITY_SCHEDULING==200112L

_POSIX_REALTIME_SIGNALS==200112L

_POSIX_SEMAPHORES==200112L

_POSIX_SHARED_MEMORY_OBJECTS==200112L

_POSIX_SYNCHRONIZED_IO==200112L

_POSIX_TIMERS==200112L

The Advanced Realtime option group implies that the following options are all defined to 200112L:

_POSIX_ADVISORY_INFO

_POSIX_CLOCK_SELECTION

(implies _POSIX_TIMERS)

_POSIX_CPUTIME

(implies _POSIX_TIMERS)

_POSIX_MONOTONIC_CLOCK

(implies _POSIX_TIMERS)

_POSIX_SPAWN

_POSIX_SPORADIC_SERVER

(implies _POSIX_PRIORITY_SCHEDULING)

_POSIX_TIMEOUTS

_POSIX_TYPED_MEMORY_OBJECTS

This option implies that the following options are all defined to 200112L:

_POSIX_THREAD_PRIO_INHERIT

_POSIX_THREAD_PRIO_PROTECT

_POSIX_THREAD_PRIORITY_SCHEDULING

This option implies that the following options are all defined to 200112L:

_POSIX_BARRIERS

(implies _POSIX_THREADS, _POSIX_THREAD_SAFE_FUNCTIONS)

_POSIX_SPIN_LOCKS

(implies _POSIX_THREADS, _POSIX_THREAD_SAFE_FUNCTIONS)

_POSIX_THREAD_CPUTIME

(implies _POSIX_TIMERS)

_POSIX_THREAD_SPORADIC_SERVER

(implies _POSIX_THREAD_PRIORITY_SCHEDULING)

This option implies that the following options are all defined to 200112L:

_POSIX_TRACE

_POSIX_TRACE_EVENT_FILTER

_POSIX_TRACE_LOG

_POSIX_TRACE_INHERIT

The following functions are present:

fattach()
fdetach()
getmsg()
getpmsg()
ioctl()
isastream()
putmsg()
putpmsg()

Functions included in the legacy option group were previously mandatory, but are now optional in this version. The following functions are present:

bcmp()
bcopy()
bzero()
ecvt()
fcvt()
ftime()
gcvt()
getcwd()
index()
mktemp()
rindex()
utimes()
wcswcs()

The following functions are present:

mmap()
munmap()
msync()

This option implies the following options:

_POSIX_FSYNC

_POSIX_MAPPED_FILES

_POSIX_MEMORY_PROTECTION

_POSIX_THREAD_ATTR_STACKADDR

_POSIX_THREAD_ATTR_STACKSIZE

_POSIX_THREAD_PROCESS_SHARED

_POSIX_THREAD_SAFE_FUNCTIONS

_POSIX_THREADS

This option may imply the following options from the XSI option groups:

Encryption (_XOPEN_CRYPT)

Realtime (_XOPEN_REALTIME)

Advanced Realtime (ADB)

Realtime Threads (_XOPEN_REALTIME_THREADS)

Advanced Realtime Threads (ADVANCED REALTIME THREADS)

Tracing (TRACING)

XSI Streams (STREAMS)

Legacy (_XOPEN_LEGACY)