pthread_mutexattr_getprioceiling(3C)									      pthread_mutexattr_getprioceiling(3C)

NAME

       pthread_mutexattr_getprioceiling, pthread_mutexattr_setprioceiling - get or set prioceiling attribute of mutex attribute object

SYNOPSIS

       cc -mt [ flag... ] file... -lpthread [ library... ]
       #include <pthread.h>

       int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *restrict attr, int *restrict prioceiling);

       int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int prioceiling int *oldceiling);

       The  pthread_mutexattr_getprioceiling()	and  pthread_mutexattr_setprioceiling()  functions, respectively, get and set the priority ceiling
       attribute of a mutex attribute object pointed to by attr, which was previously created by the pthread_mutexattr_init() function.

       The prioceiling attribute contains the priority ceiling of initialized mutexes. The values of prioceiling must be within the maximum  range
       of priorities defined by  SCHED_FIFO.

       The  prioceiling  attribute  defines the priority ceiling of initialized mutexes, which is the minimum priority level at which the critical
       section guarded by the mutex is executed. In order to avoid priority inversion, the priority ceiling of the mutex must be set to a priority
       higher than or equal to the highest priority of all the threads that may lock that mutex. The values of prioceiling must be within the max-
       imum range of priorities defined under the  SCHED_FIFO scheduling policy.

       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(3RT) and sched_get_priority_max() functions when called on the version of Solaris on which the ceiling value
       is being utilized.

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

       The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions will fail if:

       ENOSYS	       The _POSIX_THREAD_PRIO_PROTECT option is not defined and the system does not support the function.

       The pthread_mutexattr_getprioceiling() function will fail if:

       EINVAL	       The value specified by attr is NULL.

       The pthread_mutexattr_setprioceiling() functions will fail if:

       EINVAL	       The value specified by attr is NULL or prioceiling is invalid.

       The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions may fail if:

       EINVAL	       The value specified by attr or prioceiling is invalid.

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

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

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

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

								    23 Mar 2005 			      pthread_mutexattr_getprioceiling(3C)