1.\" $OpenBSD: pthread_rwlock_unlock.3,v 1.8 2013/06/05 03:44:50 tedu Exp $
2.\" Copyright (c) 1998 Alex Nash
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26.\" $FreeBSD: pthread_rwlock_unlock.3,v 1.2 1999/08/28 00:03:10 peter Exp $
27.\"
28.Dd $Mdocdate: June 5 2013 $
29.Dt PTHREAD_RWLOCK_UNLOCK 3
30.Os
31.Sh NAME
32.Nm pthread_rwlock_unlock
33.Nd release a read/write lock
34.Sh SYNOPSIS
35.In pthread.h
36.Ft int
37.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
38.Sh DESCRIPTION
39The
40.Fn pthread_rwlock_unlock
41function is used to release the read/write lock previously obtained by
42.Fn pthread_rwlock_rdlock ,
43.Fn pthread_rwlock_wrlock ,
44.Fn pthread_rwlock_tryrdlock ,
45or
46.Fn pthread_rwlock_trywrlock .
47.Sh RETURN VALUES
48If successful, the
49.Fn pthread_rwlock_unlock
50function will return zero.
51Otherwise an error number will be returned to indicate the error.
52.Pp
53The results are undefined if
54.Fa lock
55is not held by the calling thread.
56.Sh ERRORS
57The
58.Fn pthread_rwlock_unlock
59function may fail if:
60.Bl -tag -width Er
61.It Bq Er EINVAL
62The value specified by
63.Fa lock
64is invalid.
65.It Bq Er EPERM
66The current thread does not own the read/write lock.
67.El
68.Sh SEE ALSO
69.Xr pthread_rwlock_rdlock 3 ,
70.Xr pthread_rwlock_wrlock 3
71.Sh STANDARDS
72The
73.Fn pthread_rwlock_unlock
74function is expected to conform to
75.St -susv2 .
76.Sh HISTORY
77The
78.Fn pthread_rwlock_unlock
79function first appeared in
80.Fx 3.0
81and
82.Ox 2.5 .
83