pthread_mutex_setprioceiling Syntax

#include <pthread.h> 
int pthread_mutex_setprioceiling(pthread_mutex_t *restrict mutex, 
          int prioceiling, int *restrict old_ceiling);

pthread_mutex_setprioceiling() changes the priority ceiling, prioceiling, of a mutex, mutex. pthread_mutex_setprioceiling() locks a mutex if unlocked, or blocks until pthread_mutex_setprioceiling() successfully locks the mutex, changes the priority ceiling of the mutex and releases the mutex. The process of locking the mutex need not adhere to the priority protect protocol.

If pthread_mutex_setprioceiling() succeeds, the previous value of the priority ceiling is returned in old_ceiling. If pthread_mutex_setprioceiling() fails, the mutex priority ceiling remains unchanged.