Question

Is this okay to do in c?

int *i;
// do stuff

i = NULL;

i = (int *) some_func();
// do stuff

if (i != NULL)
    free(i);

i = NULL;

// do stuff
i = (int *) some_func();
// do stuff
if (i != NULL)
    free(i);

i = NULL;

Answer 1

1) That depends on the contract you have with some_func(). If some_func expects you to call free() on its return value, your code is ok.

2) It’s ok, though not terribly elegant, to reuse variables in C. It’s generally better to use different variables for different purposes. From a performance and mem-usage perspective it completely the same thing.