This variable is accessible from a debugger or your program and allows you to tune allocation diagnostics.
int afxMemDF;
Remarks
afxMemDF can have the following values as specified by the enumeration afxMemDF:
- allocMemDF Turns on debugging allocator (default setting in Debug library). 
- delayFreeMemDF Delays freeing memory. While your program frees a memory block, the allocator does not return that memory to the underlying operating system. This will place maximum memory stress on your program. 
- checkAlwaysMemDF Calls AfxCheckMemory every time memory is allocated or freed. This will significantly slow memory allocations and deallocations. 
Example
afxMemDF = allocMemDF | checkAlwaysMemDF;   
Requirements
Header: afx.h