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.\"
27.Dd July 10, 2009
28.Dt PTHREAD_RWLOCK_UNLOCK 3
29.Os
30.Sh NAME
31.Nm pthread_rwlock_unlock
32.Nd release a read/write lock
33.Sh LIBRARY
34.Lb libpthread
35.Sh SYNOPSIS
36.In pthread.h
37.Ft int
38.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
39.Sh DESCRIPTION
40The
41.Fn pthread_rwlock_unlock
42function is used to release the read/write lock previously obtained by
43.Fn pthread_rwlock_rdlock ,
44.Fn pthread_rwlock_wrlock ,
45.Fn pthread_rwlock_tryrdlock ,
46or
47.Fn pthread_rwlock_trywrlock .
48.Sh RETURN VALUES
49If successful, the
50.Fn pthread_rwlock_unlock
51function will return zero.
52Otherwise 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