131 lines
3.8 KiB
Groff
131 lines
3.8 KiB
Groff
.\" $NetBSD: semget.2,v 1.2 1997/03/27 08:20:41 mikel Exp $
|
|
.\"
|
|
.\" Copyright (c) 1995 Frank van der Linden
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" 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, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed for the NetBSD Project
|
|
.\" by Frank van der Linden
|
|
.\" 4. The name of the author may not be used to endorse or promote products
|
|
.\" derived from this software without specific prior written permission
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
|
.\"/
|
|
.Dd August 17, 1995
|
|
.Dt SEMGET 2
|
|
.Os NetBSD
|
|
.Sh NAME
|
|
.Nm semget
|
|
.Nd get semaphore set
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <sys/ipc.h>
|
|
.Fd #include <sys/sem.h>
|
|
.Ft int
|
|
.Fn semget "key_t key" "int nsems" "int semflg"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn semget
|
|
system call returns the semaphore identifier associated with
|
|
.Fa key .
|
|
|
|
A new set containing
|
|
.Fa nsems
|
|
semaphores is created if either
|
|
.Fa key
|
|
is equal to IPC_PRIVATE, or
|
|
.Fa key
|
|
does not have a semaphore set associated with it, and the IPC_CREAT bit is
|
|
set in
|
|
.Fa msgflg.
|
|
|
|
If a new set of semaphores is created, the data structure associated with it
|
|
(the
|
|
.Va semid_ds
|
|
structure, see
|
|
.Xr semctl 2 )
|
|
is intialized as follows:
|
|
.Bl -bullet
|
|
.It
|
|
.Va sem_perm.cuid
|
|
and
|
|
.Va sem_perm.uid
|
|
are set to the effective uid of the calling process.
|
|
.It
|
|
.Va sem_perm.gid
|
|
and
|
|
.Va sem_perm.cgid
|
|
are set to the effective gid of the calling process.
|
|
.It
|
|
.Va sem_perm.mode
|
|
is set to the lower 9 bits of
|
|
.Fa msgflg .
|
|
.It
|
|
.Va sem_nsems
|
|
is set to the value of
|
|
.Fa nsems
|
|
.It
|
|
.Va sem_ctime
|
|
is set to the current time
|
|
.It
|
|
.Va sem_otime
|
|
is set to 0
|
|
.El
|
|
.Sh RETURN VALUES
|
|
.Fn semget
|
|
returns a non-negative semaphore identifier if successful. Otherwise, -1
|
|
is returned and
|
|
.Va errno
|
|
is set to reflect the error.
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er EACCESS
|
|
The caller has no permission to access a semaphore set already associated with
|
|
.Fa key.
|
|
.It Bq Er EEXIST
|
|
Both IPC_CREAT and IPC_EXCL are set in
|
|
.Fa msgflg ,
|
|
and a semaphore set is already associated with
|
|
.Fa key .
|
|
.It Bq Er EINVAL
|
|
.Va nsems
|
|
is less than 0 or greater than the system limit for the number in a semaphore
|
|
set.
|
|
|
|
A semaphore set associated with
|
|
.Fa key
|
|
exists, but has fewer semaphores than the number specified in
|
|
.Fa nsems .
|
|
.It Bq Er ENOSPC
|
|
A new set of semaphores could not be created because the system limit
|
|
for the number of semaphores or the number of semaphore sets has been
|
|
reached.
|
|
.It Bq Er ENOENT
|
|
IPC_CREAT was not set in
|
|
.Fa msgflg
|
|
and no semaphore set associated with
|
|
.Fa key
|
|
was found.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr semctl 2 ,
|
|
.Xr semop 2
|