2001-08-13 16:33:00 +00:00
|
|
|
.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
|
2000-02-16 19:31:53 +00:00
|
|
|
.\" All rights reserved.
|
2001-07-15 07:53:42 +00:00
|
|
|
.\"
|
2000-02-16 19:31:53 +00:00
|
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
|
|
|
.\" modification, are permitted provided that the following conditions
|
|
|
|
|
.\" are met:
|
|
|
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
|
|
|
.\" notice(s), this list of conditions and the following disclaimer as
|
|
|
|
|
.\" the first lines of this file unmodified other than the possible
|
|
|
|
|
.\" addition of one or more copyright notices.
|
|
|
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
|
.\" notice(s), this list of conditions and the following disclaimer in
|
|
|
|
|
.\" the documentation and/or other materials provided with the
|
|
|
|
|
.\" distribution.
|
2001-07-15 07:53:42 +00:00
|
|
|
.\"
|
2000-02-16 19:31:53 +00:00
|
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
|
|
|
|
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
|
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
|
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
|
|
|
|
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
|
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
|
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
|
|
|
|
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
|
|
|
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
|
|
|
|
|
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
|
|
|
|
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
2001-07-15 07:53:42 +00:00
|
|
|
.\"
|
2000-02-16 19:31:53 +00:00
|
|
|
.\" $FreeBSD$
|
2004-07-02 16:45:56 +00:00
|
|
|
.\"
|
2000-02-16 19:31:53 +00:00
|
|
|
.Dd February 15, 2000
|
|
|
|
|
.Dt SEM_POST 3
|
|
|
|
|
.Os
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm sem_post
|
|
|
|
|
.Nd increment (unlock) a semaphore
|
2000-04-22 15:50:29 +00:00
|
|
|
.Sh LIBRARY
|
2004-01-14 20:54:16 +00:00
|
|
|
.Lb libc
|
2000-02-16 19:31:53 +00:00
|
|
|
.Sh SYNOPSIS
|
2001-10-01 16:09:29 +00:00
|
|
|
.In semaphore.h
|
2000-02-16 19:31:53 +00:00
|
|
|
.Ft int
|
|
|
|
|
.Fn sem_post "sem_t *sem"
|
|
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The
|
|
|
|
|
.Fn sem_post
|
|
|
|
|
function increments (unlocks) the semaphore pointed to by
|
|
|
|
|
.Fa sem .
|
|
|
|
|
If there are threads blocked on the semaphore when
|
|
|
|
|
.Fn sem_post
|
|
|
|
|
is called, then the highest priority thread that has been blocked the longest on
|
|
|
|
|
the semaphore will be allowed to return from
|
|
|
|
|
.Fn sem_wait .
|
2000-08-01 21:19:09 +00:00
|
|
|
.Pp
|
2003-06-08 10:13:50 +00:00
|
|
|
The
|
2000-08-01 21:19:09 +00:00
|
|
|
.Fn sem_post
|
2003-06-08 10:13:50 +00:00
|
|
|
function is signal-reentrant and may be called within signal handlers.
|
2000-02-16 19:31:53 +00:00
|
|
|
.Sh RETURN VALUES
|
2001-08-09 13:32:13 +00:00
|
|
|
.Rv -std sem_post
|
2000-02-16 19:31:53 +00:00
|
|
|
.Sh ERRORS
|
2003-06-08 10:13:50 +00:00
|
|
|
The
|
2000-02-16 19:31:53 +00:00
|
|
|
.Fn sem_post
|
2003-06-08 10:13:50 +00:00
|
|
|
function will fail if:
|
2000-02-16 19:31:53 +00:00
|
|
|
.Bl -tag -width Er
|
|
|
|
|
.It Bq Er EINVAL
|
2004-07-02 16:45:56 +00:00
|
|
|
The
|
2000-02-16 19:31:53 +00:00
|
|
|
.Fa sem
|
2004-07-02 16:45:56 +00:00
|
|
|
argument
|
2000-02-16 19:31:53 +00:00
|
|
|
points to an invalid semaphore.
|
|
|
|
|
.El
|
|
|
|
|
.Sh SEE ALSO
|
2005-07-13 13:15:22 +00:00
|
|
|
.Xr sem_getvalue 3 ,
|
2000-07-17 22:33:32 +00:00
|
|
|
.Xr sem_trywait 3 ,
|
2003-01-14 03:39:09 +00:00
|
|
|
.Xr sem_wait 3 ,
|
|
|
|
|
.Xr sem 4
|
2000-02-16 19:31:53 +00:00
|
|
|
.Sh STANDARDS
|
2003-06-08 10:13:50 +00:00
|
|
|
The
|
2000-02-16 19:31:53 +00:00
|
|
|
.Fn sem_post
|
2003-06-08 10:13:50 +00:00
|
|
|
function conforms to
|
2001-02-26 15:16:43 +00:00
|
|
|
.St -p1003.1-96 .
|
