MQSeries.net :: View topic - Losing communication between applications running C and JMS

nberger

Here's the situation:

We have one application that is written in C++ and uses MQSeries' C API.
We have another application that is written in Java and uses JMS.

They communicate P2P... the Java application sends a message to the C++ application over a named queue and the C++ application replies using the (temporary) replyToQ. This works fine.

We also have a little utility written in C (based on the MQSeries sample code) which basically reads in XML from a file, sends it P2P over a named queue, and waits for a reply on the temporary replyToQ. We generally use it to communicate with the C++ application. This also works fine.

The problem happens when all three applications are running at once. The C++ application and the Java application communicate successfully until a message is sent over the same named queue using the C utility. At this point, the C++ application does not receive any more messages from the Java application. The Java app does not log any errors on the PUT and the C++ does not log any errors on the GET. The C++ application can still receive and respond to messages sent by the C utility.

A couple of other clues:

- The Java app opens the named queue at the beginning, periodically PUTs messages on the named queue, and then closes the named queue when it is shutdown.
- The C++ opens the named queue at the beginning, periodically GETs messages off of the named queue, and then closes the named queue when it is shut down.
- The C utility opens the named queue, PUTs a message on the named queue, and then closes the named queue when it exits.

I am stumped on this one. Anyone have any ideas?!?