NetBSD/lib/libpthread/pthread_mutex_lock.3

.\" $NetBSD: pthread_mutex_lock.3,v 1.4 2003/07/04 08:36:06 wiz Exp $
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.\" Copyright (c) 1997 Brian Cully <shmit@kublai.com>
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.\" $FreeBSD: src/lib/libpthread/man/pthread_mutex_lock.3,v 1.11 2002/09/16 19:29:29 mini Exp $
.\"
.Dd January 30, 2003
.Dt PTHREAD_MUTEX_LOCK 3
.Os
.Sh NAME
.Nm pthread_mutex_lock ,
.Nm pthread_mutex_trylock
.Nd acquire a lock on a mutex
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_mutex_lock "pthread_mutex_t *mutex"
.Ft int
.Fn pthread_mutex_trylock "pthread_mutex_t *mutex"
.Sh DESCRIPTION
The
.Fn pthread_mutex_lock
function locks
.Fa mutex .
If the mutex is already locked, the calling thread will block until the
mutex becomes available.
.Pp
The
.Fn pthread_mutex_trylock
function locks
.Fa mutex .
If the mutex is already locked,
.Fn pthread_mutex_trylock
will not block waiting for the mutex, but will return an error condition.
.Sh RETURN VALUES
If successful,
.Fn pthread_mutex_lock
and
.Fn pthread_mutex_trylock
will return zero, otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
.Fn pthread_mutex_lock
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa mutex
is invalid.
.It Bq Er EDEADLK
A deadlock would occur if the thread blocked waiting for
.Fa mutex .
.El
.Pp
.Fn pthread_mutex_trylock
shall fail if:
.Bl -tag -width Er
.It Bq Er EBUSY
.Fa Mutex
is already locked.
.El
.Pp
.Fn pthread_mutex_trylock
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa mutex
is invalid.
.El
.Sh SEE ALSO
.Xr pthread_mutex_destroy 3 ,
.Xr pthread_mutex_init 3 ,
.Xr pthread_mutex_unlock 3
.Sh STANDARDS
.Fn pthread_mutex_lock
and
.Fn pthread_mutex_trylock
conform to
.St -p1003.1-96 .