return pointer to data declared in function

Question

I know this won'T work because the variable x gets destroyed when the function returns:

int* myFunction()
{
    int x = 4; return &x;
}

so how do I correctly return a pointer to something I create within the function, and what do I have to take care with? How do I avoid memory leaks?

I've also used malloc:

int* myFunction2()
{
    int* x = (int*)malloc(sizeof int); *x = 4; return x;
}

How do you correctly do this - in C and C++ ?

Answer 1

For C++, you can use a smart pointer to enforce the ownership transfer. auto_ptr or boost::shared_ptr are good options.