The debug version of the Microsoft C run-time library uses the following flags to control the heap allocation and reporting process. For more information, see CRT Debugging Techniques.
|_CRTDBG_MAP_ALLOC||Maps the base heap functions to their debug version counterparts|
|_DEBUG||Enables the use of the debugging versions of the run-time functions|
|_crtDbgFlag||Controls how the debug heap manager tracks allocations|
These flags can be defined with a /D command-line option or with a #define directive. When the flag is defined with #define, the directive must appear before the header file include statement for the routine declarations.