.\" Copyright (c) 1997 Brian Cully <shmit@kublai.com>
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.\" $FreeBSD: src/lib/libc_r/man/pthread_mutex_lock.3,v 1.5.2.4 2001/08/17 15:42:51 ru Exp $
.\"
.Dd July 30, 1998
.Dt PTHREAD_MUTEX_LOCK 3
.Os
.Sh NAME
.Nm pthread_mutex_lock
.Nd lock a mutex
.Sh SYNOPSIS
.Fd #include <pthread.h>
.Ft int
.Fo pthread_mutex_lock
.Fa "pthread_mutex_t *mutex"
.Fc
.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.
.Sh RETURN VALUES
If successful,
.Fn pthread_mutex_lock
will return zero.
Otherwise, an error number will be returned to indicate the error.
.Sh ERRORS
.Fn pthread_mutex_lock
will fail if:
.Bl -tag -width Er
.It Bq Er EDEADLK
A deadlock would occur if the thread blocked waiting for
.Fa mutex .
.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_trylock 3 ,
.Xr pthread_mutex_unlock 3
.Sh STANDARDS
.Fn pthread_mutex_lock
conforms to
.St -p1003.1-96 .