Hi, You are hitting at a genuine question here. Seeing that you use the GNU Compiler, I take it that you are running Linux. I take it, that you close down each exe, before starting the next instance. Then again, each instance starts in it's own virtual memory space. All your variables are stack based, and it suggests that Linux sets up a Random Stack Base, when a Process is started. This may be caused by the Debugger you use, if the results you display, are a result of Debugging Runs. Try it again in Retail Mode. Whereas your question is of academic interest, I cannot see any practical implications, or even, Application. Anything that assumes a Fixed Location in Memory of Anything, relating to a running program, is ultimately bad design, and doomed to failure. Kind Regards :) Bram van Kampen