Thread: Complete Port I/O and Heap Problems :: Winsock

Hi.

I am very close to finishing an IOCP Winsock program. However, there is one major bug that I have not been able to debug and determine a working solution. One reason is the fact that I do not know what causes this bug. Note that this now the only bug or at least the only one that Visual C++ Debugger finds.

Here is the message from the debugger.

Code:

HEAP[Program.exe]: HEAP: Free Heap block 36a9c8 modified at 36a9f4 after it was freed
Unhandled exception at 0x77f7f570 in Program.exe: User breakpoint.

I notice that the program crashes and Visual C++ Debugger outputs this message only when the IOCP handles multiple sockets. I do not have an accurate count, but I believe ten or more sockets will cause the program to crash. To my understand, IOCP can handle thousands of sockets. In fact, a working WSAAsyncSelect I/O model of this same program works great under hundreds of sockets at any given time.

In terms of IOCP, what could be some causes of this heap problem?

Thanks,
Kuphryn

Excellent point. Thanks.

I will check all allocations using new and make sure they remain valid.

Kuphryn