---
name: "pthread_mutex_getprioceiling"
section: "3p"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pthread_mutex_getprioceiling"
---

# pthread\_mutex\_getprioceiling(3p)

get and set the priority ceiling of a mutex (REALTIME THREADS)

## 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 .