1.\" Copyright (c) 1998 Alex Nash
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25.\" $FreeBSD: src/lib/libc_r/man/pthread_rwlock_unlock.3,v 1.2.2.2 2001/12/17 10:08:26 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 April 15, 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.  Otherwise an error number will be returned
53to indicate the error.
54.Pp
55The results are undefined if
56.Fa lock
57is not held by the calling thread.
58.Sh ERRORS
59The
60.Fn pthread_rwlock_unlock
61function may fail if:
62.Bl -tag -width Er
63.It Bq Er EINVAL
64The value specified by
65.Fa lock
66is invalid.
67.It Bq Er EPERM
68The current thread does not own the read/write lock.
69.El
70.Sh SEE ALSO
71.Xr pthread_rwlock_rdlock 3 ,
72.Xr pthread_rwlock_wrlock 3
73.Sh STANDARDS
74The
75.Fn pthread_rwlock_unlock
76function is expected to conform to
77.St -susv2 .
78.Sh HISTORY
79The
80.Fn pthread_rwlock_unlock
81function first appeared in
82.Fx 3.0 .
83