pthread_mutexattr_getprioceiling(3THR)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO

NAME

pthread_mutexattr_getprioceiling, pthread_mutexattr_setprioceiling– get and set prioceiling attribute of mutex attribute object

SYNOPSIS

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

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

DESCRIPTION

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 maximum 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(3THR).

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.

RETURN VALUES

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

ERRORS

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.

ATTRIBUTES

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

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

SEE ALSO

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

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO