Hello.

Please read this first: opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...y%20subscribed%20entities.html

The fact that you are asking questions like this means that you intend to do something incorrect with the handles. In general, they are opaque values, and you should not make assumptions like those you suggested. In reality, just between two us, we do not pass out zero handles, and as long as possible we try not to reuse the handles - but this is simply to make troubleshooting easier. All of this should be considered an implementation detail and your code must not rely on it. I do not have definitive answer on negative values, but the same applies to them.

If you are struggling with how to write your subscription code, please explain more about your issue, and I will suggest the approach we think is the best.

Best regards