Before you can use the memory diagnostics facilities, you must enable diagnostic tracing.
To enable or disable memory diagnostics
To select specific memory diagnostic features with afxMemDF
| Value | Meaning | 
| allocMemDF | Turn on diagnostic memory allocator (default). | 
| delayFreeMemDF | Delay freeing memory when calling delete or free until program exits. This will cause your program to allocate the maximum possible amount of memory. | 
| checkAlwaysMemDF | Call AfxCheckMemory every time memory is allocated or freed. | 
These values can be used in combination by performing a logical-OR operation, as shown here:
afxMemDF | delayFreeMemDF | checkAlwaysMemDF;