The Open Group Base Specifications Issue 7
IEEE Std 1003.1, 2013 Edition
Copyright © 2001-2013 The IEEE and The Open Group

#### NAME

> pthread_mutex_consistent - mark state protected by robust mutex as consistent

#### SYNOPSIS

> ``#include <pthread.h>
> int pthread_mutex_consistent(pthread_mutex_t *`mutex`);
> ``

#### DESCRIPTION

> If mutex is a robust mutex in an inconsistent state, the pthread_mutex_consistent() function can be used to mark the state protected by the mutex referenced by mutex as consistent again.

> If an owner of a robust mutex terminates while holding the mutex, the mutex becomes inconsistent and the next thread that acquires the mutex lock shall be notified of the state by the return value [EOWNERDEAD]. In this case, the mutex does not become normally usable again until the state is marked consistent.

> If the thread which acquired the mutex lock with the return value [EOWNERDEAD] terminates before calling either pthread_mutex_consistent() or pthread_mutex_unlock(), the next thread that acquires the mutex lock shall be notified about the state of the mutex by the return value [EOWNERDEAD].

> The behavior is undefined if the value specified by the mutex argument to pthread_mutex_consistent() does not refer to an initialized mutex.

#### RETURN VALUE

> Upon successful completion, the pthread_mutex_consistent() function shall return zero. Otherwise, an error value shall be returned to indicate the error.

#### ERRORS

> The pthread_mutex_consistent() function shall fail if:

> [EINVAL]
>   The mutex object referenced by mutex is not robust or does not protect an inconsistent state.

> These functions shall not return an error code of [EINTR].

The following sections are informative.

#### EXAMPLES

> None.

#### APPLICATION USAGE

> The pthread_mutex_consistent() function is only responsible for notifying the implementation that the state protected by the mutex has been recovered and that normal operations with the mutex can be resumed. It is the responsibility of the application to recover the state so it can be reused. If the application is not able to perform the recovery, it can notify the implementation that the situation is unrecoverable by a call to pthread_mutex_unlock() without a prior call to pthread_mutex_consistent(), in which case subsequent threads that attempt to lock the mutex will fail to acquire the lock and be returned [ENOTRECOVERABLE].

#### RATIONALE

> If an implementation detects that the value specified by the mutex argument to pthread_mutex_consistent() does not refer to an initialized mutex, it is recommended that the function should fail and report an [EINVAL] error.

#### FUTURE DIRECTIONS

> None.

#### SEE ALSO

> pthread_mutex_lock, pthread_mutexattr_getrobust

> XBD <pthread.h>

#### CHANGE HISTORY

> First released in Issue 7.

End of informative text.

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