From owner-freebsd-questions  Tue Mar 10 14:06:28 1998
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id OAA11501
          for freebsd-questions-outgoing; Tue, 10 Mar 1998 14:06:28 -0800 (PST)
          (envelope-from owner-freebsd-questions@FreeBSD.ORG)
Received: from luna.e-planet.com (luna.e-planet.com [192.203.7.4])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id OAA11277
          for <freebsd-questions@freebsd.org>; Tue, 10 Mar 1998 14:05:18 -0800 (PST)
          (envelope-from ARahimi@e-planet.com)
Received: by LUNA.e-planet.com with Internet Mail Service (5.0.1458.49)
	id <ZFQX8G69>; Tue, 10 Mar 1998 14:04:48 -0800
Message-ID: <0FDE707975DCD0119E75006097C2ED881C85F6@LUNA.e-planet.com>
From: "Rahimi, Ali" <ARahimi@e-planet.com>
To: freebsd-questions@FreeBSD.ORG
Subject: Problem with SYSV IPC MSG.
Date: Tue, 10 Mar 1998 14:04:46 -0800
X-Priority: 3
MIME-Version: 1.0
X-Mailer: Internet Mail Service (5.0.1458.49)
Content-Type: text/plain
Sender: owner-freebsd-questions@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG


> Hi. I have created the following two SYSV message queues:
> 
> 
> bitch:~/camera/apps/videoctrl> ipcs -q
> Message Queues:
> T     ID     KEY        MODE       OWNER    GROUP
> q  65536      23745 --rwarwarwa      ali     1001
> q  65537      23746 --rwarwarwa      ali     1001
> 
> using:
> 
> key_t kid = ftok(VIDEO_CMD_CHANNEL, 0);
> msgq = msgget(kid, IPC_CREAT|0777);
> 
> and by using ftok(...)+1.
> 
> I can reattach to both of these queues just fine. However, I can't
> read from these queues:
> 
> int err = msgrcv(msgq, &ipc_block, sizeof(ipc_block), 1, IPC_NOWAIT);
> 
> ipc_block is a small structure, and msgq is the same as what i got
> from
> msgget() (it's equal to 1 or 2, depending on what I attach to).
> However,
> I get a return value of -1 and errno=EINVAL from msgrcv(). So I tried
> using
> the ID reported by ipcs (that is, 65536 and 65537), and things work
> just
> fine. Anyone know what's up with that? The msgq returned from msgget()
> seems to be in general 65535 short of the msgid that works.
> 
>  Ali.
> 
> 

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message