pthread_mutex_getprioceiling(3C)										  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 <pthread.h>

       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);

       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 priorities 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() functions (see sched_get_priority_min(3RT)) when called  on  the  version	of
       Solaris on which the ceiling value is being utilized.

       Upon  successful completion, the pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions return  0. Otherwise, an error
       number is returned to indicate the error.

       The  pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions will fail if:

       ENOSYS	       The  option   _POSIX_THREAD_PRIO_PROTECT  is  not  defined  and	the  system  does  not	 support   the	 function.   Since
		       _POSIX_THREAD_PRIO_PROTECT is defined, this condition is not reported.

       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.

       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.

       ENOSYS	       The system does not support the priority ceiling protocol for mutexes.

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

       The pthread_mutex_getprioceiling() function may fail if:

       EINVAL	       The priority requested by prioceiling is out of range.

       The pthread_mutex_setprioceiling() function may fail if:

       EINVAL	       The priority requested by prioceiling is out of range.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

       pthread_mutex_init(3C), pthread_mutex_lock(3C), sched_get_priority_min(3RT), attributes(5), standards(5)

								    23 Mar 2005 				  pthread_mutex_getprioceiling(3C)