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.Dd July 30, 1998
.Dt PTHREAD_MUTEX_UNLOCK 3
.Os
.Sh NAME
.Nm pthread_mutex_unlock
.Nd unlock a mutex
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_mutex_unlock "pthread_mutex_t *mutex"
.Sh DESCRIPTION
If the current thread holds the lock on
.Fa mutex ,
then the
.Fn pthread_mutex_unlock
function unlocks
.Fa mutex .
.Pp
Calling
.Fn pthread_mutex_unlock
with a
.Fa mutex
that the calling thread does not hold will result 
in undefined behavior.
.Sh RETURN VALUES
If successful,
.Fn pthread_mutex_unlock
will return zero, otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
The
.Fn pthread_mutex_unlock
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa mutex
is invalid.
.It Bq Er EPERM
The current thread does not hold a lock on
.Fa mutex .
.El
.Sh SEE ALSO
.Xr pthread_mutex_destroy 3 ,
.Xr pthread_mutex_init 3 ,
.Xr pthread_mutex_lock 3 ,
.Xr pthread_mutex_trylock 3
.Sh STANDARDS
The
.Fn pthread_mutex_unlock
function conforms to
.St -p1003.1-96 .