This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
pthread_mutex_getprioceiling, pthread_mutex_setprioceiling — get and set the priority ceiling of a mutex ( REALTIME THREADS)
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);
The pthread_mutex_getprioceiling() function shall return the current priority ceiling of the mutex.
The pthread_mutex_setprioceiling() function shall attempt to lock the mutex as if by a call to pthread_mutex_lock(), except that the process of locking the mutex need not adhere to the priority protect protocol. On acquiring the mutex it shall change the mutex's priority ceiling and then release the mutex as if by a call to pthread_mutex_unlock(). When the change is successful, the previous value of the priority ceiling shall be returned in old_ceiling.
If the pthread_mutex_setprioceiling() function fails, the mutex priority ceiling shall not be changed.
If successful, the pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions shall return zero; otherwise, an error number shall be returned to indicate the error.
These functions shall fail if:
- The protocol attribute of mutex is PTHREAD_PRIO_NONE.
The pthread_mutex_setprioceiling() function shall fail if:
- The implementation requires appropriate privileges to perform the operation and the caller does not have appropriate privileges.
- The mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded.
- The mutex type is PTHREAD_MUTEX_ERRORCHECK and the current thread already owns the mutex.
- The mutex was created with the protocol attribute having the value PTHREAD_PRIO_PROTECT and the calling thread's priority is higher than the mutex's current priority ceiling, and the implementation adheres to the priority protect protocol in the process of locking the mutex.
The mutex is a robust mutex and the state protected by the mutex is not recoverable.
The pthread_mutex_setprioceiling() function may fail if:
The mutex is a robust mutex and the process containing the previous owning thread terminated while holding the mutex lock. The mutex lock shall be acquired by the calling thread and it is up to the new owner to make the state consistent (see pthread_mutex_lock()).
- A deadlock condition was detected.
- The priority requested by prioceiling is out of range.
These functions shall not return an error code of [EINTR].
The following sections are informative.
pthread_mutex_destroy(), pthread_mutex_lock(), pthread_mutex_timedlock()
The Base Definitions volume of POSIX.1‐2008, <pthread.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .
The mutex is a robust mutex and the previous owning thread terminated while holding the mutex lock. The mutex lock shall be acquired by the calling thread and it is up to the new owner to make the state consistent (see pthread_mutex_lock()).
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