On successful completion, pthread_mutex_getprioceiling() returns 0. Any other return value indicates that an error occurred.
If any of the following conditions occurs, pthread_mutexatt_getprioceiling() fails and returns the corresponding value.
If any of the following conditions occurs, pthread_mutex_getprioceiling() might fail and return the corresponding value.
EINVAL
Description:The value specified by mutex does not refer to a currently existing mutex.
EPERM
Description:The caller does not have the privilege to perform the operation.