pthread_mutexattr_getprioStandard3C)Librarpthread_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);
DESCRIPTION
The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprio‐
ceiling() 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 sec‐
tion 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 maxi‐
mum range of priorities defined under the SCHED_FIFO scheduling pol‐
icy.
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(3RT) and sched_get_priority_max() func‐
tions 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_setprio‐
ceiling() 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_setprio‐
ceiling() 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 ALSOpthread_cond_init(3C), pthread_create(3C), pthread_mutex_init(3C),
pthread_mutex_lock(3C), sched_get_priority_min(3RT), attributes(5),
standards(5)SunOS 5.10 23 Mar 2pthread_mutexattr_getprioceiling(3C)
