xref: /freebsd/share/man/man4/sem.4 (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
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.Dd February 7, 2014
26.Dt SEM 4
27.Os
28.Sh NAME
29.Nm sem
30.Nd POSIX semaphores
31.Sh SYNOPSIS
32To compile this driver into the kernel,
33place the following line in your
34kernel configuration file:
35.Bd -ragged -offset indent
36.Cd "options P1003_1B_SEMAPHORES"
37.Ed
38.Pp
39Alternatively, to load the driver as a
40module at boot time, place the following line in
41.Xr loader.conf 5 :
42.Bd -literal -offset indent
43sem_load="YES"
44.Ed
45.Pp
46To load the driver as a module at run-time, run the following
47command as root:
48.Bd -ragged -offset indent
49kldload sem
50.Ed
51.Sh DESCRIPTION
52The
53.Nm
54facility provides system calls used by the standard C library
55.Pq Pa libc
56to implement
57.Tn POSIX
58semaphores.
59This facility offers support for such functions as
60.Fn sem_init
61and
62.Fn sem_wait .
63It is available both as a kernel option for static inclusion and as a
64dynamic kernel module.
65.Sh SEE ALSO
66.Xr sem_destroy 3 ,
67.Xr sem_getvalue 3 ,
68.Xr sem_init 3 ,
69.Xr sem_open 3 ,
70.Xr sem_post 3 ,
71.Xr sem_wait 3 ,
72.Xr config 8 ,
73.Xr kldload 8 ,
74.Xr kldunload 8
75.Sh HISTORY
76The
77.Nm
78facility appeared in
79.Fx 5.0 .
80