pthread_mutex_trylock(3)pthread_mutex_trylock(3)NAMEpthread_mutex_trylock - Attempts to lock the specified mutex, without
waiting if already locked
SYNOPSIS
#include <pthread.h>
int pthread_mutex_trylock(
pthread_mutex_t *mutex );
LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so)
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
PARAMETERS
Mutex to be locked.
DESCRIPTION
This routine attempts to lock the mutex specified in the mutex argu‐
ment. When a thread calls this routine, an attempt is made to immedi‐
ately lock the mutex. If the mutex is successfully locked, this routine
returns zero (0) and the calling thread becomes the mutex's current
owner. If the specified mutex is locked when a thread calls this rou‐
tine, the calling thread does not wait for the mutex to become avail‐
able.
The behavior of this routine is as follows: For a normal, default, or
errorcheck mutex: if the mutex is locked by any thread (including the
calling thread) when this routine is called, this routine returns
[EBUSY] and the calling thread does not wait to acquire the lock. For
a normal or errorcheck mutex: if the mutex is not owned, this routine
returns zero (0) and the mutex becomes locked by the calling thread.
For a recursive mutex: if the mutex is owned by the calling thread,
this routine returns zero (0) and the mutex lock count is incremented.
(To unlock a recursive mutex, each call to pthread_mutex_trylock(3)
must be matched by a call to pthread_mutex_unlock(3).)
Use the pthread_mutexattr_settype(3) routine to set the mutex type
attribute (normal, default, recursive, or errorcheck).
RETURN VALUES
If an error condition occurs, this routine returns an integer value
indicating the type of error. Possible return values are as follows:
Successful completion. The mutex is already locked; therefore, it was
not acquired. The value specified by mutex is not a valid mutex.
ERRORS
None
SEE ALSO
Functions: pthread_mutexattr_settype(3), pthread_mutex_destroy(3),
pthread_mutex_init(3), pthread_mutex_lock(3), pthread_mutex_unlock(3)
Manuals: Guide to DECthreads and Programmer's Guide
pthread_mutex_trylock(3)
