does free() follow pointers?

Question

I'm sure it doesn't, but maybe there's black magic in it, so here's my question:

If I have a struct like this:

struct mystr {
    char * strp,
    unsigned int foo,
};

and I allocate memory for it and want to release it later. Do I have to do

free(mystr_var->strp);
free(mystr_var);

or is the last line enought, does the free() function follow the pointers and free them two?

Answer 1

No, free doesn't follow pointers, you need both lines.

I usually write a function like:

void freemystr(mystr *mystr_var)
{
    if (mystr_var)
    {
        free(mystr_var->strp);
        mystr_var->strp = NULL;
        free(mystr_var);
    }
}