Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Subject: Re: cygserver shmat
From: bertrand marquis <bertrand DOT marquis AT sysgo DOT com>
To: cygwin <cygwin AT cygwin DOT com>
In-Reply-To: <20040812104409.GA28756@cygbert.vinschen.de>
References: <1092302630 DOT 4368 DOT 3 DOT camel AT bma DOT sysgo DOT com> <20040812093246 DOT GB24822 AT cygbert DOT vinschen DOT de> <1092305627 DOT 4368 DOT 10 DOT camel AT bma DOT sysgo DOT com> <20040812104409 DOT GA28756 AT cygbert DOT vinschen DOT de>
Content-Type: multipart/mixed; boundary="=-SEf6iT+Q4o7jBrHekyab"
Organization: SYSGO AG
Message-Id: <1092312195.4368.14.camel@bma.sysgo.com>
Mime-Version: 1.0
Date: 12 Aug 2004 14:03:15 +0200
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on donald.sysgo.com
X-Spam-Level: 
X-Spam-Status: No, hits=-4.9 required=5.0 tests=BAYES_00 autolearn=no version=2.63
X-AntiVirus: checked by AntiVir MailGate (version: 2.0.1.16; AVE: 6.27.0.4; VDF: 6.27.0.7; host: mailgate.sysgo.de)

--=-SEf6iT+Q4o7jBrHekyab
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Le jeu 12/08/2004 =C3=A0 12:44, Corinna Vinschen a =C3=A9crit :
> On Aug 12 12:13, bertrand marquis wrote:
> > In fact i wasn't using the SHM_RNd flag.
> >=20
> > In details here is what i do:
> >=20
> > - get a shared segment of with size=3D SIZE (SIZE multiple of SHMLBA)
> > - attach the segment without specifying address and storing the result
> > in beginaddress
> > - attach the segment again specifying the address: endposition=3D
> > beginaddress + SIZE
> >=20
> > without SHM_RND in the second shmat i've got the error : invalid
> > argument
> >=20
> > now that i specifie SHM_RND in the flag i have the error: value to large
> > for defined type ....
> >=20
> > any idea ?
>=20
> Nope.  Not without knowing the actual values.  An strace output of
> the affected calls would be good.  Even better, create a simple testcase
> which allows to reproduce the behaviour.  Just the minimum of necessary
> code.
>=20
>=20
> Corinna


Ok,

i have made a minimum program showing the problem.
You can try specifying or not SHM_RND in the second shmat, without i
have INvalid argument error and with i have value too large for defined
data type.


thanks
bertrand

--=-SEf6iT+Q4o7jBrHekyab
Content-Disposition: attachment; filename=testshm.c
Content-Type: text/x-c; name=testshm.c; charset=UTF-8
Content-Transfer-Encoding: 7bit

#include <cygwin/shm.h>
#include <cygwin/ipc.h>
#include <stdio.h>
#include <errno.h>

#define SHM_R           0400
#define SHM_W           0200

main()
{
	int sh_key,sz;
	unsigned int size=1000000;
	unsigned char *begin,*end,*tmp;
	
	sz = getpagesize();
	size= (size / sz)*sz;

	sh_key = shmget (IPC_PRIVATE, size, IPC_CREAT | IPC_EXCL | SHM_R | SHM_W);
	if (sh_key != -1)
	{
		printf("sh_key=%i\n",sh_key);
		begin = (unsigned char *)shmat (sh_key, NULL, 0);
		
		if ( begin != -1)
		{
			tmp = begin + size;
			printf("begin=%d, tmp=%d\n",(int)begin,(int)tmp);
			
			end = (unsigned char *) shmat(sh_key,tmp,SHM_RND);
			
			if (tmp == end )
			{
				printf("end=%i\n",(int)end);
				
				shmdt(end);
			}
			else
			{
				printf("error in shmat : %s\n",strerror(errno));
			}
	
			shmdt(begin);
		}
		else
		{
			printf("error in shmat : %s\n",strerror(errno));
		}
		
		shmctl (sh_key, IPC_RMID, NULL);
	}
	else
	{
		printf("error in shmget : %s\n",strerror(errno));
	}

}


--=-SEf6iT+Q4o7jBrHekyab
Content-Type: text/plain; charset=us-ascii

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/
--=-SEf6iT+Q4o7jBrHekyab--