c++ - what to do if debug runs fine, but release crashes

Question

I have an application that runs just fine in the debug build, but when I start it in the release build, I get a

unhandled Exception at 0x0043b134 in myapp.exe: 0xC0000005:
Access violation while reading at position 0x004bd96c

If I click on 'break' it tells me that there are no symbols loaded and the source code can't be displayed.

What can I do in such a situation to track down the problem?

Answer 1

This kind of problem is often due to unitialized variables. I'd start there looking for your problem.

Debug mode is more forgiving because it is often configured to initialize variables that have not been explicitly initialized.

Perhaps you're deleting an unitialized pointer. In debug mode it works because pointer was nulled and delete ptr will be ok on NULL. On release it's some rubbish, then delete ptr will actually cause a problem.