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
|
|
|
.\" $FreeBSD$
|
2003-01-14 04:12:33 +00:00
|
|
|
.Dd January 14, 2003
|
2000-02-16 19:31:53 +00:00
|
|
|
.Dt SEM_INIT 3
|
|
|
|
|
.Os
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm sem_init
|
|
|
|
|
.Nd initialize an unnamed semaphore
|
2000-04-22 15:50:29 +00:00
|
|
|
.Sh LIBRARY
|
|
|
|
|
.Lb libc_r
|
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_init "sem_t *sem" "int pshared" "unsigned int value"
|
|
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The
|
|
|
|
|
.Fn sem_init
|
|
|
|
|
function initializes the unnamed semaphore pointed to by
|
|
|
|
|
.Fa sem
|
|
|
|
|
to have the value
|
|
|
|
|
.Fa value .
|
|
|
|
|
A non-zero value for
|
|
|
|
|
.Fa pshared
|
2003-01-14 04:12:33 +00:00
|
|
|
specifies a shared semaphore that can be used by any process
|
|
|
|
|
that can access
|
|
|
|
|
.Fa sem .
|
2000-02-16 19:31:53 +00:00
|
|
|
.Pp
|
|
|
|
|
Following a successful call to
|
|
|
|
|
.Fn sem_init ,
|
|
|
|
|
.Fa sem
|
|
|
|
|
can be used as an argument in subsequent calls to
|
|
|
|
|
.Fa sem_wait ,
|
|
|
|
|
.Fa sem_trywait ,
|
|
|
|
|
.Fa sem_post ,
|
|
|
|
|
and
|
|
|
|
|
.Fa sem_destroy .
|
|
|
|
|
.Fa sem
|
|
|
|
|
is no longer valid after a successful call to
|
|
|
|
|
.Fa sem_destroy .
|
|
|
|
|
.Sh RETURN VALUES
|
2001-08-09 13:32:13 +00:00
|
|
|
.Rv -std sem_init
|
2000-02-16 19:31:53 +00:00
|
|
|
.Sh ERRORS
|
|
|
|
|
.Fn sem_init
|
|
|
|
|
will fail if:
|
|
|
|
|
.Bl -tag -width Er
|
|
|
|
|
.It Bq Er EINVAL
|
|
|
|
|
.Fa value
|
|
|
|
|
exceeds SEM_VALUE_MAX.
|
|
|
|
|
.It Bq Er ENOSPC
|
|
|
|
|
Memory allocation error.
|
2003-01-14 04:12:33 +00:00
|
|
|
.It Bq Er ENFILE
|
|
|
|
|
The system limit on semaphores
|
|
|
|
|
.Pq Dv SEM_NSEMS_MAX
|
|
|
|
|
has been reached.
|
2000-02-16 19:31:53 +00:00
|
|
|
.El
|
|
|
|
|
.Sh SEE ALSO
|
2000-07-17 22:33:32 +00:00
|
|
|
.Xr sem_destroy 3 ,
|
2000-02-16 19:31:53 +00:00
|
|
|
.Xr sem_post 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
|
|
|
|
|
.Fn sem_init
|
2001-02-26 15:16:43 +00:00
|
|
|
conforms to
|
|
|
|
|
.St -p1003.1-96 .
|
