When is pointer to array useful?

Question

I can declare:

int (*ap)[N];

So ap is pointer to int array of size N. Why is this ever useful? If I pass it to function, what usefu

Answer 1

There are situations where you want to pass the memory location across programs. e.g a windows API might expect you to pass a pointer to data structure or an array where as you are programming in some other language, say c#. Windows API does not care how the target language handles array's, for windows API it is just a stream of bytes in memory and it will fill it, send it back to you. to avoid cross language type missmatch in some cases we use pointer to array rather than implicit array name as pointer. More over it is not guaranteed that the implicit array name is a long pointer, some compilers might optimize it to be a relative value withing segment. a pointer to an array guarantees that it is of the order of machine register size and you can point to a location anywhere in the available RAM.