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1 | .\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>. |
2 | .\" All rights reserved. | |
3 | .\" | |
4 | .\" Redistribution and use in source and binary forms, with or without | |
5 | .\" modification, are permitted provided that the following conditions | |
6 | .\" are met: | |
7 | .\" 1. Redistributions of source code must retain the above copyright | |
8 | .\" notice(s), this list of conditions and the following disclaimer as | |
9 | .\" the first lines of this file unmodified other than the possible | |
10 | .\" addition of one or more copyright notices. | |
11 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
12 | .\" notice(s), this list of conditions and the following disclaimer in | |
13 | .\" the documentation and/or other materials provided with the | |
14 | .\" distribution. | |
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16 | .\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY | |
17 | .\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
18 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
19 | .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE | |
20 | .\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
21 | .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
22 | .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR | |
23 | .\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | |
24 | .\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE | |
25 | .\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, | |
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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 $ | |
9964d5ef | 29 | .Dd April 15, 2009 |
984263bc MD |
30 | .Dt SEM_POST 3 |
31 | .Os | |
32 | .Sh NAME | |
33 | .Nm sem_post | |
34 | .Nd increment (unlock) a semaphore | |
35 | .Sh LIBRARY | |
9964d5ef | 36 | .Lb libpthread |
984263bc MD |
37 | .Sh SYNOPSIS |
38 | .In semaphore.h | |
39 | .Ft int | |
40 | .Fn sem_post "sem_t *sem" | |
41 | .Sh DESCRIPTION | |
42 | The | |
43 | .Fn sem_post | |
44 | function increments (unlocks) the semaphore pointed to by | |
45 | .Fa sem . | |
46 | If there are threads blocked on the semaphore when | |
47 | .Fn sem_post | |
48 | is called, then the highest priority thread that has been blocked the longest on | |
49 | the semaphore will be allowed to return from | |
50 | .Fn sem_wait . | |
51 | .Pp | |
52 | .Fn sem_post | |
53 | is signal-reentrant and may be called within signal handlers. | |
54 | .Sh RETURN VALUES | |
55 | .Rv -std sem_post | |
56 | .Sh ERRORS | |
57 | .Fn sem_post | |
58 | will fail if: | |
59 | .Bl -tag -width Er | |
60 | .It Bq Er EINVAL | |
61 | .Fa sem | |
62 | points to an invalid semaphore. | |
63 | .El | |
64 | .Sh SEE ALSO | |
65 | .Xr sem_trywait 3 , | |
66 | .Xr sem_wait 3 | |
67 | .Sh STANDARDS | |
68 | .Fn sem_post | |
69 | conforms to | |
70 | .St -p1003.1-96 . |