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RE: 1.7.9: mq_unlink/mq_open leaks handles
- 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
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 mqd_t struct.
Manuel
> -----Original Message-----
> Sent: Monday, April 04, 2011 2:50 PM
> Subject: 1.7.9: mq_unlink/mq_open leaks handles
>
> Hallo,
>
> 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.
>
> Tested with this DLL: cygwin1-20110327.dll
>
> Thanks,
>
> Manuel
>
>
>
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <mqueue.h>
> #include <string.h>
> #include <errno.h>
> #include <fcntl.h>
> #include <unistd.h>
>
> int main(void)
> {
> int res;
> int i = 0;
> char msgQueueTestName[] = "./testQueue";
> mqd_t testQueue;
> struct mq_attr attrQueue;
> memset(&attrQueue,0x00,sizeof(attrQueue));
> attrQueue.mq_maxmsg = 10; /* room for X messages in the queue */
> attrQueue.mq_msgsize = 20; /* maximum size of a message */
>
> while(1)
> {
> sleep(1);
> i++;
> printf("Loop #%d\n", i); fflush(stdout);
>
> // Remove old queues before trying to create a new one.
> res = mq_unlink(msgQueueTestName);
> if ((res == -1) && (errno != 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);
> }
>
> testQueue = mq_open(msgQueueTestName, O_RDWR | O_CREAT | O_EXCL,
> S_IRWXU | S_IRWXG, &attrQueue);
> if( testQueue == (mqd_t)-1 )
> {
> printf("Failed to open msg queue %s: %s %d\n", msgQueueTestName,
> sys_errlist[errno],errno);
> }
>
> res = mq_unlink(msgQueueTestName);
> if (res == -1)
> {
> printf("Failed to unlink msg queue %s: %s %d\n",
> msgQueueTestName, sys_errlist[errno],errno);
> }
> }
>
> return EXIT_SUCCESS;
> }
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