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POSIXOPTIONS(7)		   Linux Programmer's Manual	       POSIXOPTIONS(7)

NAME

posixoptions - optional parts of the POSIX standard

DESCRIPTION

The POSIX standard (the information below is from POSIX.1-2001) describes a set of behaviours and interfaces for a compliant system. However, many interfaces are optional and there are feature test macros to test the availability of interfaces at compile time, and functions sysconf(3), fpathconf(3), pathconf(3), confstr(3) to do this at run time. From shell scripts one can use getconf(1). For more detail, see sysconf(3). We give the name of the POSIX abbreviation, the option, the name of the sysconf() parameter used to inquire about the option, and possibly a very short description. Much more precise detail can be found in the POSIX standard itself, versions of which can nowadays be accessed freely on the web. ADV - _POSIX_ADVISORY_INFO - _SC_ADVISORY_INFO The advisory functions posix_fadvise(), posix_fallocate(), posix_memalign(), posix_madvise() are present. AIO - _POSIX_ASYNCHRONOUS_IO - _SC_ASYNCHRONOUS_IO The header <aio.h> is present. The functions aio_cancel(), aio_error(), aio_fsync(), aio_read(), aio_return(), aio_suspend(), aio_write(), lio_listio() are present. BAR - _POSIX_BARRIERS - _SC_BARRIERS This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS options. The functions pthread_barrier_destroy(), pthread_barrier_init(), pthread_barrier_wait(), pthread_barrierattr_destroy(), pthread_barrierattr_init() are present. --- - POSIX_CHOWN_RESTRICTED 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 non-root can only set the group of a file to one of the groups it belongs to. This affects the functions chown(), fchown(). CS - _POSIX_CLOCK_SELECTION - _SC_CLOCK_SELECTION This option implies the _POSIX_TIMERS option. The functions pthread_condattr_getclock(), pthread_condattr_setclock(), clock_nanosleep() are present. If CLOCK_REALTIME is changed by the function clock_set- time(), then this affects all timers set for an absolute time. CPT - _POSIX_CPUTIME - _SC_CPUTIME The clockID CLOCK_PROCESS_CPUTIME_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. --- - _POSIX_FILE_LOCKING - _SC_FILE_LOCKING This option has been deleted. Not in final XPG6. FSC - _POSIX_FSYNC - _SC_FSYNC The function fsync() is present. IP6 - _POSIX_IPV6 - _SC_IPV6 Internet Protocol Version 6 is supported. --- - _POSIX_JOB_CONTROL - _SC_JOB_CONTROL If this option is in effect (as it always is under POSIX.1-2001) then the system implements POSIX-style job control, and the functions setpgid(), tcdrain(), tcflush(), tcgetpgrp(), tcsendbreak(), tcsetattr(), tcsetpgrp() are present. MF - _POSIX_MAPPED_FILES - _SC_MAPPED_FILES Shared memory is supported. The include file <sys/mman.h> is present. The functions mmap(), msync(), munmap() are present. ML - _POSIX_MEMLOCK - _SC_MEMLOCK Shared memory can be locked into core. The functions mlockall(), munlockall() are present. MR/MLR - _POSIX_MEMLOCK_RANGE - _SC_MEMLOCK_RANGE More precisely, ranges can be locked into core. The functions mlock(), munlock() are present. MPR - _POSIX_MEMORY_PROTECTION - _SC_MEMORY_PROTECTION The function mprotect() is present. MSG - _POSIX_MESSAGE_PASSING - _SC_MESSAGE_PASSING The include file <mqueue.h> is present. The functions mq_close(), mq_getattr(), mq_notify(), mq_open(), mq_receive(), mq_send(), mq_setattr(), mq_unlink() are present. MON - _POSIX_MONOTONIC_CLOCK - _SC_MONOTONIC_CLOCK CLOCK_MONOTONIC is supported. This option implies the _POSIX_TIMERS option. Affected functions are aio_suspend(), clock_getres(), clock_gettime(), clock_settime(), timer_create(). --- - _POSIX_MULTI_PROCESS - _SC_MULTI_PROCESS This option has been deleted. Not in final XPG6. --- - _POSIX_NO_TRUNC 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 compo- nent. PIO - _POSIX_PRIORITIZED_IO - _SC_PRIORITIZED_IO This option says that one can specify priorities for asynchronous I/O. This affects the functions aio_read(), aio_write(). PS - _POSIX_PRIORITY_SCHEDULING - _SC_PRIORITY_SCHEDULING The include file <sched.h> is present. The functions sched_get_priority_max(), sched_get_priority_min(), sched_getparam(), sched_getscheduler(), sched_rr_get_interval(), sched_setparam(), sched_setscheduler(), sched_yield() are present. If also _POSIX_SPAWN is in effect, then the functions posix_spawnattr_getschedparam(), posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedparam(), posix_spawnattr_setschedpolicy() are present. RS - _POSIX_RAW_SOCKETS Raw sockets are supported. Affected functions are getsockopt(), set- sockopt(). --- - _POSIX_READER_WRITER_LOCKS - _SC_READER_WRITER_LOCKS This option implies the _POSIX_THREADS option. Conversely, under POSIX.1-2001 the _POSIX_THREADS option implies this option. The functions 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() are present. RTS - _POSIX_REALTIME_SIGNALS - _SC_REALTIME_SIGNALS Realtime signals are supported. The functions sigqueue(), sigtimedwait(), sigwaitinfo() are present. --- - _POSIX_REGEXP - _SC_REGEXP If this option is in effect (as it always is under POSIX.1-2001) then POSIX regular expressions are supported and the functions regcomp(), regerror(), regexec(), regfree() are present. --- - _POSIX_SAVED_IDS - _SC_SAVED_IDS 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. Affected functions are exec(), kill(), seteuid(), setegid(), setgid(), setuid(). SEM - _POSIX_SEMAPHORES - _SC_SEMAPHORES The include file <semaphore.h> is present. The functions sem_close(), sem_destroy(), sem_getvalue(), sem_init(), sem_open(), sem_post(), sem_trywait(), sem_unlink(), sem_wait() are present. SHM - _POSIX_SHARED_MEMORY_OBJECTS - _SC_SHARED_MEMORY_OBJECTS The functions mmap(), munmap(), shm_open(), shm_unlink() are present. --- - _POSIX_SHELL - _SC_SHELL If this option is in effect (as it always is under POSIX.1-2001), the function system() is present. SPN - _POSIX_SPAWN - _SC_SPAWN This option describes support for process creation in a context where it is difficult or impossible to use fork(), e.g. because no MMU is present. If _POSIX_SPAWN is in effect, then the include file <spawn.h> and the functions 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() are present. If also _POSIX_PRIORITY_SCHEDULING is in effect, then the functions posix_spawnattr_getschedparam(), posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedparam(), posix_spawnattr_setschedpolicy() are present. SPI - _POSIX_SPIN_LOCKS - _SC_SPIN_LOCKS This option implies the _POSIX_THREADS and _POSIX_THREAD_SAFE_FUNCTIONS options. The functions pthread_spin_destroy(), pthread_spin_init(), pthread_spin_lock(), pthread_spin_trylock(), pthread_spin_unlock() are present. SS - _POSIX_SPORADIC_SERVER - _SC_SPORADIC_SERVER The scheduling policy SCHED_SPORADIC is supported. This option implies the _POSIX_PRIORITY_SCHEDULING option. Affected functions are sched_setparam(), sched_setscheduler(). SIO - _POSIX_SYNCHRONIZED_IO - _SC_SYNCHRONIZED_IO Affected functions are open(), msync(), fsync(), fdatasync(). TSA - _POSIX_THREAD_ATTR_STACKADDR - _SC_THREAD_ATTR_STACKADDR Affected functions are pthread_attr_getstack(), pthread_attr_getstackaddr(), pthread_attr_setstack(), pthread_attr_setstackaddr(). TSS - _POSIX_THREAD_ATTR_STACKSIZE - _SC_THREAD_ATTR_STACKSIZE Affected functions are pthread_attr_getstack(), pthread_attr_getstacksize(), pthread_attr_setstack(), pthread_attr_setstacksize(). TCT - _POSIX_THREAD_CPUTIME - _SC_THREAD_CPUTIME The clockID CLOCK_THREAD_CPUTIME_ID is supported. This option implies the _POSIX_TIMERS option. Affected functions are pthread_getcpuclockid(), clock_getres(), clock_gettime(), clock_settime(), timer_create(). TPI - _POSIX_THREAD_PRIO_INHERIT - _SC_THREAD_PRIO_INHERIT Affected functions are pthread_mutexattr_getprotocol(), pthread_mutexattr_setprotocol(). TPP - _POSIX_THREAD_PRIO_PROTECT - _SC_THREAD_PRIO_PROTECT Affected functions are pthread_mutex_getprioceiling(), pthread_mutex_setprioceiling(), pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), pthread_mutexattr_setprioceiling(), pthread_mutexattr_setprotocol(). TPS - _POSIX_THREAD_PRIORITY_SCHEDULING - _SC_THREAD_PRIORITY_SCHEDULING If this option is in effect, the different threads inside a process can run with different priorities and/or different schedulers. Affected functions are pthread_attr_getinheritsched(), pthread_attr_getschedpolicy(), pthread_attr_getscope(), pthread_attr_setinheritsched(), pthread_attr_setschedpolicy(), pthread_attr_setscope(), pthread_getschedparam(), pthread_setschedparam(), pthread_setschedprio(). TSH - _POSIX_THREAD_PROCESS_SHARED - _SC_THREAD_PROCESS_SHARED Affected functions are pthread_barrierattr_getpshared(), pthread_barrierattr_setpshared(), pthread_condattr_getpshared(), pthread_condattr_setpshared(), pthread_mutexattr_getpshared(), pthread_mutexattr_setpshared(), pthread_rwlockattr_getpshared(), pthread_rwlockattr_setpshared(). TSF - _POSIX_THREAD_SAFE_FUNCTIONS - _SC_THREAD_SAFE_FUNCTIONS Affected functions are 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(). TSP - _POSIX_THREAD_SPORADIC_SERVER - _SC_THREAD_SPORADIC_SERVER This option implies the _POSIX_THREAD_PRIORITY_SCHEDULING option. Affected functions are sched_getparam(), sched_setparam(), sched_setscheduler(). THR - _POSIX_THREADS - _SC_THREADS Basic support for POSIX threads is available. The functions 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() are present. TMO - _POSIX_TIMEOUTS - _SC_TIMEOUTS The functions mq_timedreceive(), mq_timedsend(), pthread_mutex_timedlock(), pthread_rwlock_timedrdlock(), pthread_rwlock_timedwrlock(), sem_timedwait(), posix_trace_timedgetnext_event() are present. TMR - _POSIX_TIMERS - _SC_TIMERS The functions clock_getres(), clock_gettime(), clock_settime(), nanosleep(), timer_create(), timer_delete(), timer_gettime(), timer_getoverrun(), timer_settime() are present. TRC - _POSIX_TRACE - _SC_TRACE POSIX tracing is available. The functions 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() are present. TEF - _POSIX_TRACE_EVENT_FILTER - _SC_TRACE_EVENT_FILTER This option implies the _POSIX_TRACE option. The functions 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() are present. TRI - _POSIX_TRACE_INHERIT - _SC_TRACE_INHERIT Tracing children of the traced process is supported. This option implies the _POSIX_TRACE option. The functions posix_trace_attr_getinherited(), posix_trace_attr_setinherited() are present. TRL - _POSIX_TRACE_LOG - _SC_TRACE_LOG This option implies the _POSIX_TRACE option. The functions 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() are present. TYM - _POSIX_TYPED_MEMORY_OBJECTS - _SC_TYPED_MEMORY_OBJECT The functions posix_mem_offset(), posix_typed_mem_get_info(), posix_typed_mem_open() are present. --- - _POSIX_VDISABLE Always present (probably 0). Value to set a changeable special control character to to indicate that it is disabled.

XOPEN EXTENSIONS

_XOPEN_CRYPT, _XOPEN_LEGACY, _XOPEN_REALTIME, _XOPEN_REALTIME_THREADS, _XOPEN_UNIX.

SEE ALSO

sysconf(3) POSIX 2003-08-24 POSIXOPTIONS(7)

1994 Man-cgi 1.15, Panagiotis Christias <christia@theseas.ntua.gr>