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;
}

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Answer 1

There is another approach - declare x static. In this case it will be located in data segment, not on stack, therefore it is available (and persistent) during the program runtime.

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

Please note that assignment x=4 will be performed only on first call of myFunction:

int *foo = myFunction();   // foo is 4
*foo = 10;                 // foo is 10
*foo = myFunction();       // foo is 10

NB! Using function-scope static variables isn't tread-safe technique.