Is this a double free in C?

Question

Normally, if a pointer is freed twice, it\'s a double free. For example,

char *ptr;
ptr=malloc(5 * sizeof(*ptr));
free(ptr);
free(ptr);

The

Answer 1

Yes this is a double free (and a very bad thing to do). The ptr1 is a pointer to the memory allocated by the malloc. It is the same location that ptr was pointing to. By freeing ptr and ptr1 you are freeing the same memory twice.