.\" Copyright (c) 2002 Tim J. Robbins
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.\" $FreeBSD: head/share/man/man4/sem.4 261611 2014-02-07 22:04:56Z brueffer $
.\"
.Dd February 7, 2014
.Dt SEM 4
.Os
.Sh NAME
.Nm sem
.Nd POSIX semaphores
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "options P1003_1B_SEMAPHORES"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
sem_load="YES"
.Ed
.Pp
To load the driver as a module at run-time, run the following
command as root:
.Bd -ragged -offset indent
kldload sem
.Ed
.Sh DESCRIPTION
The
.Nm
facility provides system calls used by the standard C library
.Pq Pa libc
to implement
.Tn POSIX
semaphores.
This facility offers support for such functions as
.Fn sem_init
and
.Fn sem_wait .
It is available both as a kernel option for static inclusion and as a
dynamic kernel module.
.Sh SEE ALSO
.Xr sem_destroy 3 ,
.Xr sem_getvalue 3 ,
.Xr sem_init 3 ,
.Xr sem_open 3 ,
.Xr sem_post 3 ,
.Xr sem_wait 3 ,
.Xr config 8 ,
.Xr kldload 8 ,
.Xr kldunload 8
.Sh HISTORY
The
.Nm
facility appeared in
.Fx 5.0 .