1.\" Copyright (c) 1998 Alex Nash
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25.\" $FreeBSD: src/share/man/man3/pthread_rwlock_unlock.3,v 1.10 2007/10/22 10:08:00 ru Exp $
26.\" $DragonFly: src/lib/libc_r/man/pthread_rwlock_unlock.3,v 1.3 2006/02/17 19:35:07 swildner Exp $
27.\"
28.Dd July 10, 2009
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 LIBRARY
35.Lb libpthread
36.Sh SYNOPSIS
37.In pthread.h
38.Ft int
39.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
40.Sh DESCRIPTION
41The
42.Fn pthread_rwlock_unlock
43function is used to release the read/write lock previously obtained by
44.Fn pthread_rwlock_rdlock ,
45.Fn pthread_rwlock_wrlock ,
46.Fn pthread_rwlock_tryrdlock ,
47or
48.Fn pthread_rwlock_trywrlock .
49.Sh RETURN VALUES
50If successful, the
51.Fn pthread_rwlock_unlock
52function will return zero.
53Otherwise an error number will be returned
54to indicate the error.
55.Pp
56The results are undefined if
57.Fa lock
58is not held by the calling thread.
59.Sh ERRORS
60The
61.Fn pthread_rwlock_unlock
62function may fail if:
63.Bl -tag -width Er
64.It Bq Er EINVAL
65The value specified by
66.Fa lock
67is invalid.
68.It Bq Er EPERM
69The current thread does not own the read/write lock.
70.El
71.Sh SEE ALSO
72.Xr pthread_rwlock_rdlock 3 ,
73.Xr pthread_rwlock_wrlock 3
74.Sh STANDARDS
75The
76.Fn pthread_rwlock_unlock
77function is expected to conform to
78.St -susv2 .
79.Sh HISTORY
80The
81.Fn pthread_rwlock_unlock
82function first appeared in
83.Fx 3.0 .
84