1.\" $OpenBSD: sem_init.3,v 1.6 2013/11/20 03:26:56 tedu Exp $ 2.\" 3.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice(s), this list of conditions and the following disclaimer as 11.\" the first lines of this file unmodified other than the possible 12.\" addition of one or more copyright notices. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice(s), this list of conditions and the following disclaimer in 15.\" the documentation and/or other materials provided with the 16.\" distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 19.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 22.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 25.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 26.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 27.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 28.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29.\" 30.\" $FreeBSD: src/lib/libc_r/man/sem_init.3,v 1.11 2001/10/01 16:09:09 ru Exp $ 31.Dd $Mdocdate: November 20 2013 $ 32.Dt SEM_INIT 3 33.Os 34.Sh NAME 35.Nm sem_init 36.Nd initialize an unnamed semaphore 37.Sh SYNOPSIS 38.In semaphore.h 39.Ft int 40.Fn sem_init "sem_t *sem" "int pshared" "unsigned int value" 41.Sh DESCRIPTION 42The 43.Fn sem_init 44function initializes the unnamed semaphore pointed to by 45.Fa sem 46to have the value 47.Fa value . 48A non-zero value for 49.Fa pshared 50specifies a shared semaphore that can be used by multiple processes. 51.Pp 52Following a successful call to 53.Fn sem_init , 54.Fa sem 55can be used as an argument in subsequent calls to 56.Fa sem_wait , 57.Fa sem_trywait , 58.Fa sem_post , 59and 60.Fa sem_destroy . 61.Fa sem 62is no longer valid after a successful call to 63.Fa sem_destroy . 64.Sh RETURN VALUES 65.Rv -std sem_init 66.Sh ERRORS 67It is an error to call 68.Fn sem_destroy 69on a named semaphore created by 70.Fn sem_open . 71.Pp 72.Fn sem_init 73will fail if: 74.Bl -tag -width Er 75.It Bq Er EINVAL 76.Fa value 77exceeds SEM_VALUE_MAX. 78.It Bq Er ENOSPC 79Memory allocation error. 80.El 81.Sh SEE ALSO 82.Xr sem_destroy 3 , 83.Xr sem_getvalue 3 , 84.Xr sem_open 3 , 85.Xr sem_post 3 , 86.Xr sem_wait 3 87.Sh STANDARDS 88.Fn sem_init 89conforms to 90.St -p1003.1-96 . 91