why pointer to pointer is needed to allocate memory in function

Question

I have a segmentation fault in the code below, but after I changed it to pointer to pointer, it is fine. Could anybody give me any reason?

void memory(int *          


        

Answer 1

You need a pointer to pointer because you need to return the value of the newly allocated pointer.

There is three ways to return that value (2 if you use C):

• use a pointer, here it is a pointer to pointer
• use a reference, here it is a reference to pointer
• use the return value of the function, so make memory return a int * instead of void

The third way has definitely my preference.

(and not, I won't admit you could also use a global, it's not a fourth way but an horror).