NAME

pthread_mutex_setprioceiling, pthread_mutex_getprioceiling - change the priority ceiling of a mutex (REALTIME THREADS)

 SYNOPSIS

#include <pthread.h>

int pthread_mutex_setprioceiling(pthread_mutex_t *mutex,
    int prioceiling, int *old_ceiling);
int pthread_mutex_getprioceiling(const pthread_mutex_t *mutex,
    int *prioceiling);

 DESCRIPTION

The pthread_mutex_getprioceiling() function returns the current priority 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 ceiling 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 priority ceiling is not changed.

 RETURN VALUE

If successful, the pthread_mutex_setprioceiling() and pthread_mutex_getprioceiling() functions return zero. 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 implementation does not support the function.

The pthread_mutex_setprioceiling() and pthread_mutex_getprioceiling() functions may fail if:

[EINVAL]

The priority requested by prioceiling is out of range.

[EINVAL]

The value specified by mutex does not refer to a currently existing mutex.

[ENOSYS]

The implementation does not support the priority ceiling protocol for mutexes.

[EPERM]

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

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

pthread_mutex_init(), pthread_mutex_lock(), pthread_mutex_unlock(), pthread_mutex_trylock(), <pthread.h>.

DERIVATION

Derived from the POSIX Threads Extension (1003.1c-1995)