pthread_mutex_getprioceiling or pthread_mutex_setprioceiling Subroutine
Purpose
Gets and sets the priority ceiling of a mutex.
Syntax
#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 subroutine returns the current priority ceiling of the mutex.
The pthread_mutex_setprioceiling subroutine 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 shall be returned in old_ceiling. The process of locking the mutex need not adhere to the priority protect protocol.
If the pthread_mutex_setprioceiling subroutine fails, the mutex priority ceiling is not changed.
Return Values
If successful, the pthread_mutex_getprioceiling and pthread_mutex_setprioceiling subroutines return zero; otherwise, an error number is returned to indicate the error.
Error Codes
| Item | Description |
|---|---|
| [EINVAL] | The priority requested by the prioceiling parameter is out of range. |
| [EINVAL] | The value specified by the mutex parameter does not refer to a currently existing mutex. |
| [ENOSYS] | This function is not supported (draft 7). |
| [ENOTSUP] | This function is not supported together with checkpoint/restart. |
| [EPERM] | The caller does not have the privilege to perform the operation in a strictly standards conforming environment where environment variable XPG_SUS_ENV=ON. |
The pthread_mutex_setprioceiling subroutine can fail because of one of the following errors:
| Item | Description |
|---|---|
| ENOTRECOVERABLE | The protected state of the mutex cannot be recovered. |
| EOWNERDEAD | The mutex is a robust mutex, and the process of the thread that owns the mutex terminated while holding the mutex lock. |