xref: /freebsd/share/man/man4/sem.4 (revision 4db78cacdee1b6f3b7880eb8c5560e8edaf91698)
1.\" Copyright (c) 2002 Tim J. Robbins
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, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
25.\" $FreeBSD$
26.\"
27.Dd February 7, 2014
28.Dt SEM 4
29.Os
30.Sh NAME
31.Nm sem
32.Nd POSIX semaphores
33.Sh SYNOPSIS
34To compile this driver into the kernel,
35place the following line in your
36kernel configuration file:
37.Bd -ragged -offset indent
38.Cd "options P1003_1B_SEMAPHORES"
39.Ed
40.Pp
41Alternatively, to load the driver as a
42module at boot time, place the following line in
43.Xr loader.conf 5 :
44.Bd -literal -offset indent
45sem_load="YES"
46.Ed
47.Pp
48To load the driver as a module at run-time, run the following
49command as root:
50.Bd -ragged -offset indent
51kldload sem
52.Ed
53.Sh DESCRIPTION
54The
55.Nm
56facility provides system calls used by the standard C library
57.Pq Pa libc
58to implement
59.Tn POSIX
60semaphores.
61This facility offers support for such functions as
62.Fn sem_init
63and
64.Fn sem_wait .
65It is available both as a kernel option for static inclusion and as a
66dynamic kernel module.
67.Sh SEE ALSO
68.Xr sem_destroy 3 ,
69.Xr sem_getvalue 3 ,
70.Xr sem_init 3 ,
71.Xr sem_open 3 ,
72.Xr sem_post 3 ,
73.Xr sem_wait 3 ,
74.Xr config 8 ,
75.Xr kldload 8 ,
76.Xr kldunload 8
77.Sh HISTORY
78The
79.Nm
80facility appeared in
81.Fx 5.0 .
82