Move pthread* manpages to lib/libpthread as they are not libc_r specific.
[dragonfly.git] / lib / libpthread / sem_post.3
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1.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
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28.\" $FreeBSD: src/lib/libc_r/man/sem_post.3,v 1.1.2.8 2001/12/17 10:08:26 ru Exp $
1de703da 29.\" $DragonFly: src/lib/libc_r/man/sem_post.3,v 1.2 2003/06/17 04:26:48 dillon Exp $
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30.Dd February 15, 2000
31.Dt SEM_POST 3
32.Os
33.Sh NAME
34.Nm sem_post
35.Nd increment (unlock) a semaphore
36.Sh LIBRARY
37.Lb libc_r
38.Sh SYNOPSIS
39.In semaphore.h
40.Ft int
41.Fn sem_post "sem_t *sem"
42.Sh DESCRIPTION
43The
44.Fn sem_post
45function increments (unlocks) the semaphore pointed to by
46.Fa sem .
47If there are threads blocked on the semaphore when
48.Fn sem_post
49is called, then the highest priority thread that has been blocked the longest on
50the semaphore will be allowed to return from
51.Fn sem_wait .
52.Pp
53.Fn sem_post
54is signal-reentrant and may be called within signal handlers.
55.Sh RETURN VALUES
56.Rv -std sem_post
57.Sh ERRORS
58.Fn sem_post
59will fail if:
60.Bl -tag -width Er
61.It Bq Er EINVAL
62.Fa sem
63points to an invalid semaphore.
64.El
65.Sh SEE ALSO
66.Xr sem_trywait 3 ,
67.Xr sem_wait 3
68.Sh STANDARDS
69.Fn sem_post
70conforms to
71.St -p1003.1-96 .