C++ Memory Leak Using STL Containers

Question

The following code is giving me a memory leak (using Visual Studio):

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#include <vector>
#include <memory>

struct Listener {};

struct Subject
{
    std::vector<Listener*> listeners;
};

int main(void)
{
    Subject subject;
    _CrtDumpMemoryLeaks();
    return 1;
}

I presume this is because the STL vector container is using memory on the heap when the Subject class is instantiated. How do I ensure that the vector container is destroyed when the program exits? (I've tried deleting the container in the Subject destructor, but that doesn't seem to work).

Answer 1

The vector is destroyed when the program exits, you don't need to ensure it. You do need to ensure that _CrtDumpMemoryLeaks is called after that destruction if you don't want it to report the allocated memory as "leaked":

int main()
{
    { Subject subject; }
    _CrtDumpMemoryLeaks();
    return 1;
}