The function int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *restrict attr, int *restrict prioceiling); Gets the priority ceiling attribute of a mutexattr object (which was prev. created by the function pthread_mutexattr_init()). Upon success, it returns 0, and stores the value of the prioceiling in 'prioceiling'. It MAY fail if: [EINVAL] - 'attr' or 'prioceiling' is invalid. [EPERM] - The caller doesn't have the privilege to perform the operation. Shall not return an error code of [EINTR]