InitCVIRTE generates error message "Unhandled exception in "MyApp.exe": 0xC0000005: Access violation reading location 0x00000000."

Question

Hi,
I have converted a LabWindows CVI project to Visual Studio 2005. When I start the application i debug mode I get the message "Unhandled exception at 0x685662ba in EE352-500V.exe: 0xC0000005: Access violation reading location 0x00000000."
It comes when the application calls:  InitCVIRTE in this context:
int __stdcall WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
// Initialize LabWindows/CVI run-time library
if (InitCVIRTE (hInstance, 0, 0) == 0)
return -1; /* out of memory */
The debugger indicates that value of hInstance is 0x00400000 {unused=9460301} 
Can someone give me a solution to this problem. I have done some search on the Web without success.
Thanks!

Answer 1

I think that exception might be coming from the data execution prevention service that is part of Win XP SP2.  The OS thinks that you're somehow trying to execute in the data segment and kills the process.  It's intended to catch worms and viruses.
You can turn this service off for non-Microsoft programs using the control panel.
Many pointer handling errors now report as this exception instead of as a memory violation exception.  That looks like a null pointer derefence to me.
Menchar
Message Edited by menchar on 11-09-2007 07:12 PM