What's the difference between a null pointer and a void pointer?

Question

Whats the difference between a Null pointer & a Void pointer?

Answer 1

A null pointer is guaranteed to not compare equal to a pointer to any object. It's actual value is system dependent and may vary depending on the type. To get a null int pointer you would do

int* p = 0;

A null pointer will be returned by malloc on failure.

We can test if a pointer is null, i.e. if malloc or some other function failed simply by testing its boolean value:

if (p) {
    /* Pointer is not null */
} else {
    /* Pointer is null */
}

A void pointer can point to any type and it is up to you to handle how much memory the referenced objects consume for the purpose of dereferencing and pointer arithmetic.