PTHREAD_MUTEX_GETPRIOCEILING(3POSIX)

PROLOG
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.

NAME
pthread_mutex_getprioceiling, pthread_mutex_setprioceiling — get and set the priority ceiling of a mutex (REALTIME THREADS)

SYNOPSIS

#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 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.

RETURN VALUE
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.

ERRORS
These functions shall fail if:

EINVAL
    The protocol attribute of mutex is PTHREAD_PRIO_NONE.

EPERM
    The implementation requires appropriate privileges to perform the operation and the caller does not have appropriate privileges.

The pthread_mutex_setprioceiling() function shall fail if:

EAGAIN
    The mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded.

EDEADLK
    The mutex type is PTHREAD_MUTEX_ERRORCHECK and the current thread already owns the mutex.

EINVAL
    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.

ENOTRECOVERABLE
    The mutex is a robust mutex and the state protected by the mutex is not recoverable.

EOWNERDEAD
    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()).

The pthread_mutex_setprioceiling() function may fail if:

EDEADLK
    A deadlock condition was detected.

EINVAL
    The priority requested by prioceiling is out of range.

EOWNERDEAD
    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()).

These functions shall not return an error code of [EINTR].

The following sections are informative.

EXAMPLES
None.

APPLICATION USAGE
None.

RATIONALE
None.

FUTURE DIRECTIONS
None.

SEE ALSO
pthread_mutex_destroy(), pthread_mutex_lock(), pthread_mutex_timedlock()

The Base Definitions volume of POSIX.1-2017, <pthread.h>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .