pthread_mutex_trylock

Locks a mutex. If the mutex is already locked, the calling thread does not wait for the mutex to become available.

Syntax

pthread_mutex_trylock( mutex );

Argument Data Type Access

mutex opaque pthread_mutex_t read

C Binding

int
pthread_mutex_trylock (
pthread_mutex_t *mutex);

Arguments

mutex: Mutex locked.

Description

This routine locks a mutex and its behavior varies based on the kind of mutex. If the specified mutex is locked when a thread calls this routine, the calling thread does not wait for the mutex to become available.

When a thread calls this routine, an attempt is made to immediately lock the mutex. If the mutex is successfully locked, 1 is returned and the current thread is then the mutex's current owner.

If a recursive mutex is owned by the current thread, 1 is returned and the mutex is relocked. (To unlock a recursive mutex, each call to pthread_mutex_trylock must be matched by a call to pthread_mutex_ unlock.) If the mutex is locked by another thread when this routine is called, 0 is returned and the thread does not wait to acquire the lock. If a fast mutex is owned by the current thread, 0 is returned.

Return Values

If an error condition occurs, this routine returns -1 and sets errno to the corresponding error value. Possible return values are as follows:

Return Error Description

1 Successful completion. 0 The mutex is already locked; therefore, it was not acquired. -1 [EINVAL] The value specified by mutex is invalid.