pthread_mutexattr_gettype() — Get type of mutex attribute object

#define _OPEN_THREADS
#include <pthread.h>

int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *type);

SUSV3:

#define _UNIX03_THREADS 
#include <pthread.h>
int pthread_mutexattr_gettype(const pthread_mutexattr_t * __restrict__attr,
                              int * __restrict__type);

The values for the attribute type are:

PTHREAD_MUTEX_NORMAL

A normal type mutex does not detect deadlock. That is, a thread attempting to relock this mutex without first unlocking it will deadlock. The mutex is either in a locked or unlocked state for a thread.

PTHREAD_MUTEX_ERRORCHECK

An errorcheck type mutex provides error checking. That is, a thread attempting to relock this mutex without first unlocking it will return with an error. The mutex is either in a locked or unlocked state for a thread. If a thread attempts to relock a mutex that it has already locked, it will return with an error. If a thread attempts to unlock a mutex that is unlocked, it will return with an error.

PTHREAD_MUTEX_RECURSIVE

A recursive type mutex permits a thread to lock many times. That is, a thread attempting to relock this mutex without first unlocking will succeed. This type of mutex must be unlocked the same number to times it is locked before the mutex will be returned to an unlocked state. If locked, an error is returned.

PTHREAD_MUTEX_DEFAULT

The default type mutex is mapped to a normal type mutex which does not detect deadlock. That is, a thread attempting to relock this mutex without first unlocking it will deadlock. The mutex is either in a locked or unlocked state for a thread. The normal mutex is the default type mutex.

__MUTEX_NONRECURSIVE

A nonrecursive mutex can be locked only once. That is, the mutex is either in a locked or unlocked state for a thread. If a thread attempts to lock a mutex that it has already locked, an error is returned.

__MUTEX_RECURSIVE

A recursive mutex can be locked more than once by the same thread. A count of the number of times the mutex has been locked is maintained. The mutex is unlocked when pthread_mutex_unlock() is performed an equal number of times.

__MUTEX_NONRECURSIVE + __MUTEX_NODEBUG

A nonrecursive mutex can be given an additional attribute, NODEBUG. This indicates that state changes to this mutex will not be reported to the debug interface, even if present.

__MUTEX_RECURSIVE + __MUTEX_NODEBUG

A recursive mutex can be given an additional attribute, NODEBUG. This indicates that state changes to this mutex will not be reported to the debug interface, even if present.

If unsuccessful, pthread_mutexattr_gettype() returns -1 and sets errno to one of the following values:

Error Code

Description

EINVAL

The value specified for attr is not valid.