18e234adfSJason Evans.\" Copyright (C) 2000 Jason Evans <jasone@freebsd.org>. 2b0a1b4f8SJason Evans.\" All rights reserved. 3b0a1b4f8SJason Evans.\" 4b0a1b4f8SJason Evans.\" Redistribution and use in source and binary forms, with or without 5b0a1b4f8SJason Evans.\" modification, are permitted provided that the following conditions 6b0a1b4f8SJason Evans.\" are met: 7b0a1b4f8SJason Evans.\" 1. Redistributions of source code must retain the above copyright 8b0a1b4f8SJason Evans.\" notice(s), this list of conditions and the following disclaimer as 9b0a1b4f8SJason Evans.\" the first lines of this file unmodified other than the possible 10b0a1b4f8SJason Evans.\" addition of one or more copyright notices. 11b0a1b4f8SJason Evans.\" 2. Redistributions in binary form must reproduce the above copyright 12b0a1b4f8SJason Evans.\" notice(s), this list of conditions and the following disclaimer in 13b0a1b4f8SJason Evans.\" the documentation and/or other materials provided with the 14b0a1b4f8SJason Evans.\" distribution. 15b0a1b4f8SJason Evans.\" 16b0a1b4f8SJason Evans.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17b0a1b4f8SJason Evans.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18b0a1b4f8SJason Evans.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19b0a1b4f8SJason Evans.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 20b0a1b4f8SJason Evans.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21b0a1b4f8SJason Evans.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22b0a1b4f8SJason Evans.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23b0a1b4f8SJason Evans.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24b0a1b4f8SJason Evans.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25b0a1b4f8SJason Evans.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 26b0a1b4f8SJason Evans.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27b0a1b4f8SJason Evans.\" 28b0a1b4f8SJason Evans.\" $FreeBSD$ 29b0a1b4f8SJason Evans.Dd February 15, 2000 30b0a1b4f8SJason Evans.Dt SEM_INIT 3 31b0a1b4f8SJason Evans.Os 32b0a1b4f8SJason Evans.Sh NAME 33b0a1b4f8SJason Evans.Nm sem_init 34b0a1b4f8SJason Evans.Nd initialize an unnamed semaphore 35d8a78688SAlexey Zelkin.Sh LIBRARY 36d8a78688SAlexey Zelkin.Lb libc_r 37b0a1b4f8SJason Evans.Sh SYNOPSIS 38b0a1b4f8SJason Evans.Fd #include <semaphore.h> 39b0a1b4f8SJason Evans.Ft int 40b0a1b4f8SJason Evans.Fn sem_init "sem_t *sem" "int pshared" "unsigned int value" 41b0a1b4f8SJason Evans.Sh DESCRIPTION 42b0a1b4f8SJason EvansThe 43b0a1b4f8SJason Evans.Fn sem_init 44b0a1b4f8SJason Evansfunction initializes the unnamed semaphore pointed to by 45b0a1b4f8SJason Evans.Fa sem 46b0a1b4f8SJason Evansto have the value 47b0a1b4f8SJason Evans.Fa value . 48b0a1b4f8SJason EvansA non-zero value for 49b0a1b4f8SJason Evans.Fa pshared 50b0a1b4f8SJason Evansspecifies a shared semaphore that can be used by multiple processes, which this 51b0a1b4f8SJason Evansimplementation is not capable of. 52b0a1b4f8SJason Evans.Pp 53b0a1b4f8SJason EvansFollowing a successful call to 54b0a1b4f8SJason Evans.Fn sem_init , 55b0a1b4f8SJason Evans.Fa sem 56b0a1b4f8SJason Evanscan be used as an argument in subsequent calls to 57b0a1b4f8SJason Evans.Fa sem_wait , 58b0a1b4f8SJason Evans.Fa sem_trywait , 59b0a1b4f8SJason Evans.Fa sem_post , 60b0a1b4f8SJason Evansand 61b0a1b4f8SJason Evans.Fa sem_destroy . 62b0a1b4f8SJason Evans.Fa sem 63b0a1b4f8SJason Evansis no longer valid after a successful call to 64b0a1b4f8SJason Evans.Fa sem_destroy . 65b0a1b4f8SJason Evans.Sh RETURN VALUES 66b0a1b4f8SJason EvansIf successful, 67b0a1b4f8SJason Evans.Fn sem_init 68b0a1b4f8SJason Evansreturns 0. Otherwise, -1 is returned and 69b0a1b4f8SJason Evans.Va errno 70b0a1b4f8SJason Evansis set to indicate the type of 71b0a1b4f8SJason Evanserror. 72b0a1b4f8SJason Evans.Sh ERRORS 73b0a1b4f8SJason Evans.Fn sem_init 74b0a1b4f8SJason Evanswill fail if: 75b0a1b4f8SJason Evans.Bl -tag -width Er 76b0a1b4f8SJason Evans.It Bq Er EINVAL 77b0a1b4f8SJason Evans.Fa value 78b0a1b4f8SJason Evansexceeds SEM_VALUE_MAX. 79b0a1b4f8SJason Evans.It Bq Er ENOSPC 80b0a1b4f8SJason EvansMemory allocation error. 81b0a1b4f8SJason Evans.It Bq Er EPERM 82b0a1b4f8SJason EvansUnable to initialize a shared semaphore. 83b0a1b4f8SJason Evans.El 84b0a1b4f8SJason Evans.Sh SEE ALSO 8582db3da3SJason Evans.Xr sem_destroy 3 , 86b0a1b4f8SJason Evans.Xr sem_post 3 , 8782db3da3SJason Evans.Xr sem_trywait 3 , 8882db3da3SJason Evans.Xr sem_wait 3 89b0a1b4f8SJason Evans.Sh STANDARDS 90b0a1b4f8SJason Evans.Fn sem_init 91b0a1b4f8SJason Evansconforms to ISO/IEC 9945-1 ANSI/IEEE 92b0a1b4f8SJason Evans.Pq Dq Tn POSIX 93b0a1b4f8SJason EvansStd 1003.1 1996 Edition. 94b0a1b4f8SJason Evans.Pp 95b0a1b4f8SJason EvansThis implementation does not support shared semaphores, and reports this fact 96b0a1b4f8SJason Evansby setting 97b0a1b4f8SJason Evans.Va errno 98b0a1b4f8SJason Evansto EPERM. This is perhaps a stretch of the intention of POSIX, but is 99b0a1b4f8SJason Evanscompliant, with the caveat that 100b0a1b4f8SJason Evans.Fn sem_init 101b0a1b4f8SJason Evansalways reports a permissions error when an attempt to create a shared semaphore 102b0a1b4f8SJason Evansis made. 103