Shared memory of same DLL in different 32 bit processes is sometimes different in a terminal session on Windows server 2008 with 64 bit

Question

We have an 32 bit application consisting of some processes. They communicate with shared memory of a DLL used by every process. Shared memory is build with global variables in C++ by "#pragma data_seg ("Shared")".

When running this application sometime during starting a new process in addition to an existing (first) process we observe that the shared memory of both processes is not the same. All new started processes cannot communicate with the first process. After stopping all of our processes and restarting the application (with some processes) everything works fine. But sometime or other after successfully starting and finishing new processes the problem occurs again.

Running on all other Windows versions or terminal sessions on Windows server 2003 our application never got this problem. Is there any new "feature" on Windows server 2008 that might disturb the hamony of our application?

Answer 1

Windows runs 32bit programs under a wrapper called Wow64. Are your processes all running under the same Wow64 wrapper (use Process Explorer to see the process tree).