Manual Pages for UNIX Operating System command usage for man pthread_mutex_getprioceiling

Standard C Library Functions     pthread_mutex_getprioceiling(3C)



NAME
     pthread_mutex_getprioceiling, pthread_mutex_setprioceiling -
     change priority ceiling of a mutex

SYNOPSIS
     cc -mt [ flag... ] file... -lpthread [ library... ]
     #include 

     int pthread_mutex_getprioceiling(const pthread_mutex_t *restrict mutex,
          int *restrict prioceiling);


     int pthread_mutex_setprioceiling(pthread_mutex_t *restrict mutex,
          int prioceiling, int *restrict old_ceiling);


DESCRIPTION
     The  pthread_mutex_getprioceiling()  function  returns   the
     current priority ceiling of the mutex.


     The pthread_mutex_setprioceiling() function either locks the
     mutex if it is unlocked, or blocks until it can successfully
     lock the mutex, then it changes the mutex's priority ceiling
     and  releases  the mutex. When the change is successful, the
     previous value  of  the  priority  ceiling  is  returned  in
     old_ceiling.  The  process  of  locking  the  mutex need not
     adhere to the priority protect protocol.


     If the pthread_mutex_setprioceiling()  function  fails,  the
     mutex priority ceiling is not changed.


     The ceiling value should be drawn from the range of  priori-
     ties  for the SCHED_FIFO policy. When a thread acquires such
     a mutex, the policy  of  the  thread  at  mutex  acquisition
     should  match  that from which the ceiling value was derived
     (SCHED_FIFO, in this  case).     If  a  thread  changes  its
     scheduling   policy  while  holding  a  ceiling  mutex,  the
     behavior of pthread_mutex_lock() and  pthread_mutex_unlock()
     on this mutex is undefined. See pthread_mutex_lock(3C).


     The ceiling value should not  be  treated  as  a  persistent
     value  resident  in  a  pthread_mutex_t that is valid across
     upgrades of Solaris. The semantics  of  the  actual  ceiling
     value  are determined by the existing priority range for the
     SCHED_FIFO     policy,     as     returned       by      the
     sched_get_priority_min()  and sched_get_priority_max() func-
     tions (see sched_get_priority_min(3C)) when  called  on  the
     version  of  Solaris  on  which  the  ceiling value is being



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Standard C Library Functions     pthread_mutex_getprioceiling(3C)



     utilized.

RETURN VALUES
     Upon          successful           completion,           the
     pthread_mutex_getprioceiling()                           and
     pthread_mutex_setprioceiling() functions return   0.  Other-
     wise, an error number is returned to indicate the error.

ERRORS
     The            pthread_mutex_getprioceiling()            and
     pthread_mutex_setprioceiling() functions may fail if:

     EINVAL    The value specified by mutex does not refer  to  a
               currently existing mutex.



     The pthread_mutex_setprioceiling() function will fail if:

     EINVAL    The mutex was not initialized  with  its  protocol
               attribute       having      the      value      of
               PTHREAD_PRIO_PROTECT.


     EINVAL    The priority requested by prioceiling  is  out  of
               range.


     EPERM     The caller does not have the privilege to  perform
               the operation.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:




















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Standard C Library Functions     pthread_mutex_getprioceiling(3C)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     pthread_mutex_init(3C),              pthread_mutex_lock(3C),
     sched_get_priority_min(3C), attributes(5), standards(5)









































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