pthread_mutex_getprioceilStandard C Library Fupthread_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);
DESCRIPTION
The pthread_mutex_getprioceiling() function returns the current prior‐
ity 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 ceil‐
ing 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 prior‐
ity 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 ceil‐
ing 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.
RETURN VALUES
Upon successful completion, the pthread_mutex_getprioceiling() and
pthread_mutex_setprioceiling() functions return 0. Otherwise, an error
number is returned to indicate the error.
ERRORS
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 cur‐
rently existing mutex.
ENOSYS The system does not support the priority ceiling proto‐
col 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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOpthread_mutex_init(3C), pthread_mutex_lock(3C), sched_get_prior‐
ity_min(3RT), attributes(5), standards(5)SunOS 5.10 23 Mar 2005 pthread_mutex_getprioceiling(3C)
