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From: Manuel Wienand <Manuel DOT Wienand AT ubitronix DOT com>
To: "cygwin AT cygwin DOT com" <cygwin AT cygwin DOT com>
Date: Mon, 4 Apr 2011 15:06:35 +0200
Subject: RE: 1.7.9: mq_unlink/mq_open leaks handles
Message-ID: <0C11C5BF0B29FD43A8D0250F711D497F89DC3AE22D@ex01-ubitronix.ubitronix.local>
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Grmpf,

sorry for the spam. Just realized that mq_close is still needed, even if we=
 don't want to open the queue again.
mq_unlink just deletes the file while mq_close frees the resources of the m=
qd_t struct.

Manuel


> -----Original Message-----
> Sent: Monday, April 04, 2011 2:50 PM
> Subject: 1.7.9: mq_unlink/mq_open leaks handles
>=20
> Hallo,
>=20
> it seems that mq_unlink and/or mq_open forget to close some handles (5
> to be precise).
> How to test:
> Execute the following code and watch the number of handles in the
> windows task-manager (processes tab, you can add a column there). For
> me it increases by 5 with every loop.
>=20
> Tested with this DLL: cygwin1-20110327.dll
>=20
> Thanks,
>=20
> Manuel
>=20
>=20
>=20
>=20
> #include <stdio.h>
> #include <stdlib.h>
> #include <mqueue.h>
> #include <string.h>
> #include <errno.h>
> #include <fcntl.h>
> #include <unistd.h>
>=20
> int main(void)
> {
>   int res;
>   int i =3D 0;
>   char msgQueueTestName[] =3D "./testQueue";
>   mqd_t testQueue;
>   struct mq_attr  attrQueue;
>   memset(&attrQueue,0x00,sizeof(attrQueue));
>   attrQueue.mq_maxmsg  =3D 10;  /* room for X messages in the queue */
>   attrQueue.mq_msgsize =3D 20;  /* maximum size of a message */
>=20
>   while(1)
>   {
>     sleep(1);
>     i++;
>     printf("Loop #%d\n", i); fflush(stdout);
>=20
>     // Remove old queues before trying to create a new one.
>     res =3D mq_unlink(msgQueueTestName);
>     if ((res =3D=3D -1) && (errno !=3D ENOENT))
>     {
>       // Don't print anything if the queue can't be unlinked, because
> it doesn't exist.
>      printf("Failed to unlink msg queue %s: %s %d\n", msgQueueTestName,
> sys_errlist[errno],errno);
>     }
>=20
>     testQueue =3D mq_open(msgQueueTestName, O_RDWR | O_CREAT | O_EXCL,
> S_IRWXU | S_IRWXG, &attrQueue);
>     if( testQueue =3D=3D (mqd_t)-1 )
>     {
>       printf("Failed to open msg queue %s: %s %d\n", msgQueueTestName,
> sys_errlist[errno],errno);
>     }
>=20
>     res =3D mq_unlink(msgQueueTestName);
>     if (res =3D=3D -1)
>     {
>       printf("Failed to unlink msg queue %s: %s %d\n",
> msgQueueTestName, sys_errlist[errno],errno);
>     }
>   }
>=20
> 	return EXIT_SUCCESS;
> }

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