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 behaviors 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(3) 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 following advisory functions are present:

       posix_fadvise(),
       posix_fallocate(),
       posix_memalign(),
       posix_madvise().

   AIO - _POSIX_ASYNCHRONOUS_IO - _SC_ASYNCHRONOUS_IO
   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().

   BAR - _POSIX_BARRIERS - _SC_BARRIERS
   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().

   --- - 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 nonroot can set the group
   of a file only 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 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.

   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  following
   functions are present:

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

   MF - _POSIX_MAPPED_FILES - _SC_MAPPED_FILES
   Shared  memory is supported.  The include file <sys/mman.h> is present.
   The following functions are present: mmap(), msync(), munmap().

   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  following  functions  are
   present:

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

   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
   component.

   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  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().

   RS - _POSIX_RAW_SOCKETS
   Raw  sockets  are  supported.   Affected  functions  are  getsockopt(),
   setsockopt().

   --- - _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 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().

   RTS - _POSIX_REALTIME_SIGNALS - _SC_REALTIME_SIGNALS
   Realtime signals are supported.  The following functions are present:

       sigqueue(),
       sigtimedwait(),
       sigwaitinfo().

   --- - _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 following functions are
   present:

       regcomp(),
       regerror(),
       regexec(),
       regfree().

   --- - _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 following functions are
   present:

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

   SHM - _POSIX_SHARED_MEMORY_OBJECTS - _SC_SHARED_MEMORY_OBJECTS
   The following functions are present:

       mmap(),
       munmap(),
       shm_open(),
       shm_unlink().

   --- - _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(), 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().

   SPI - _POSIX_SPIN_LOCKS - _SC_SPIN_LOCKS
   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().

   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 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().

   TMO - _POSIX_TIMEOUTS - _SC_TIMEOUTS
   The following functions are present:

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

   TMR - _POSIX_TIMERS - _SC_TIMERS
   The following functions are present:

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

   TRC - _POSIX_TRACE - _SC_TRACE
   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().

   TEF - _POSIX_TRACE_EVENT_FILTER - _SC_TRACE_EVENT_FILTER
   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().

   TRI - _POSIX_TRACE_INHERIT - _SC_TRACE_INHERIT
   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().

   TRL - _POSIX_TRACE_LOG - _SC_TRACE_LOG
   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().

   TYM - _POSIX_TYPED_MEMORY_OBJECTS - _SC_TYPED_MEMORY_OBJECT
   The following functions are present:

       posix_mem_offset(),
       posix_typed_mem_get_info(),
       posix_typed_mem_open().

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

XOPEN EXTENSIONS

   _XOPEN_CRYPT,  _XOPEN_LEGACY, _XOPEN_REALTIME, _XOPEN_REALTIME_THREADS,
   _XOPEN_UNIX.

SEE ALSO

   sysconf(3), standards(7)

COLOPHON

   This page is part of release 4.09 of the Linux  man-pages  project.   A
   description  of  the project, information about reporting bugs, and the
   latest    version    of    this    page,    can     be     found     at
   https://www.kernel.org/doc/man-pages/.

                              2007-12-21                   POSIXOPTIONS(7)

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