Question

I have a host program that implicitly (with libs and their DLLs) loads DLLs. When I make a memory leak on purpose, in my host program, the CrtDbg* functions detect the leak. When I on purpose make a memory leak in one of the DLLs the leak is not detected.

Note: in my host, I activate the _CrtDumpMemoryLeaks function after the main function has terminated.

Answer 1

More than likely your DLLs are statically linking to the CRT. (or they are a retail build, but your EXE is a debug build). Either way, you have more than one heap. When you call _CrtDeumpMemoryLeaks, it can only track the unreleased memory allocations for the binary that calls is made from. You have two options.

• Change all your code (DLL and EXE) to link to the same MSVCRT DLL instead of static linking. In the project settings for each binary, choose “Multithreaded DEBUG DLL” or “Multithreaded DLL” as the linkage type to the CRT. Don not choose static. Then all DLLs and the EXE will share the same heap.

OR

• Export a function out of each DLL called “DetectMemoryLeaks” (or similarly named function for the other DLLs so there’s not a naming conflict). This function just calls _CrtDumpMemoryLeaks. From your EXE, call this function around the same time you call _CrtDumpMemoryLeaks. Each heap from each DLL will get checked for leaks.