( void* )0 is NULL, in that NULL is (most usually) #defined to be ( void* )0. But the literal 0 in a pointer context doesn't guarentee that the null pointer is actually all bits zero.

To put it another way, if you have a literal zero in a pointer context, the compiler will replace it with the machine's representation of a null pointer, which may or may not be a machine word with all bits zero.

I think that's right...