Why does my OSG MFC based application show memory leaks

From: http://www.vis-sim.com/3dsceneBB/viewtopic.php?t=1027

There is a known issue/BUG with MFC, were MFC makes a call to 
_CrtDumpMemoryLeaks() in the destructor of the _AFX_DEBUG_STATE, followed by _CrtSetDbgFlag() which sets it to ~_CRTDBG_LEAK_CHECK_DF (therefor disabling memory leak test at *true* program exit) This destructor is called at exit (i.e. atexit()), but before statics residing in dlls and others are destroyed, resulting in many false memory leaks are reported 

As to fix any real memory leaks, you have the source ... also you can do a 
google to see how others have gotten around this issue to get at any real 
leaks. 

The MFC memory leak will not go away as Microsoft have no reason to fix it( it been there for many years) as MFC is a deprecated API as far as they are concerned 


Another solution to the MFC and wrong memory leak reports. You need to make your MFC dll load first during application start up and unload last during application exit. I managed to do this by making the following change. 

In your MFC application. 

. Goto project settings. In there, make the following changes for theDebug build. 
. General->Use of MFC->Use Standard Windows Libraries. 
. Add _AFXDLL to C/C++->Preprocessor->Preprocessor Definitions. 
. Add mfc80??.lib (in my case it is mfc80ud.lib) as a first dependency or at least before osg libs to Linker->Input->Additional 
Dependencies. 

You can find what the other mfc libs are in your visual studio install directory\VC\atlmfc\lib. You don't need to do this release mode. 


Other solutions possible : 

If you add a MFC dependency to osg dlls that should also create the desired effect. Change the Use of MFC setting to General->Use of 
MFC->Use MFC In a Shared DLL in your debug builds of osg libraries. 

This should add MFC dll dependency to your osg dll in debug so forcing MFC dll to unload after the osg dlls but as I said I did not actually 
try this. 

Rebuild the MFC dlls with the following change. At least remove the "_CrtDumpMemoryLeaks()" call in 
_AFX_DEBUG_STATE's destructor. It is in VS_INSTALL\VC\atlmfc\src\mfc\dumpinit.cpp. The makefile is in VS_INSTALL\VC\atlmfc\src\atlmfc.mak. I did not try this, either.