Now, if your DLL doesn't use MFC, all I've said isn't possible because MFC uses it's own allocator (basically by overloading operators new and delete ). So, I have a little question: is any good reason for you to develop DLLs which do not use. You don't need to call _CrtDumpMemoryLeaks. MFC calls this function when all user libraries are unloaded. _CrtDumpMemoryLeaks just prints all undeleted allocations. So, if you call this function, it just prints everything that is allocated for now. Topic archived. No new replies allowed. How can I tell Visual c also to show me the memory leaks in a called dll? thx Ralf Reply With quot; December 20th, 2012, 05:05 AM #2 Re: Show memory leaks in dll? VC program prints memory leaks by calling _CrtDumpMemoryLeaks just before the program. If the DLL uses MFC (it's a MFC-extension DLL or regular DLL using MFC) and you have source files, then for detecting the source of memory leaks is enough to have defined DEBUG _NEW in each implemetation file (as Alex suggested before). Is this MFC application or not? Do you request memory leaks dump? Do you redefine new to DEBUG _NEW? Where is the code that creates memory leaks in both your posts? What is Dll type, how it is loaded by main executable? _CRTDBG _MAP_ALLOC is used for malloc tracking, not for C new operations. It is not related here. So, if the whole project is MFC, every C allocation which is not released, must be printed in the end.