[spc476]

Nope. There is no need in C for all pointers to be the same size. An implementation is free (and there indeed, exist some) where a char* is a different size from an int. You can* safely cast any data pointer to void, and a void back to any data pointer. POSIX requires that function pointers can do this; the C standard doesn't require it.

Now, that said, it is possible to write generic link list routines (I've done it) but the devil is in the details.