1.\" Copyright (c) 1998 Alex Nash
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25.Dd August 4, 1998
26.Dt PTHREAD_RWLOCK_UNLOCK 3
27.Os
28.Sh NAME
29.Nm pthread_rwlock_unlock
30.Nd release a read/write lock
31.Sh LIBRARY
32.Lb libpthread
33.Sh SYNOPSIS
34.In pthread.h
35.Ft int
36.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
37.Sh DESCRIPTION
38The
39.Fn pthread_rwlock_unlock
40function is used to release the read/write lock previously obtained by
41.Fn pthread_rwlock_rdlock ,
42.Fn pthread_rwlock_wrlock ,
43.Fn pthread_rwlock_tryrdlock ,
44or
45.Fn pthread_rwlock_trywrlock .
46.Sh RETURN VALUES
47If successful, the
48.Fn pthread_rwlock_unlock
49function will return zero.
50Otherwise an error number will be returned
51to 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 .
81