pointer question

[cobb at utcsstat.UUCP]

If anyone out there is still not convinced about "p = p + 4" portability,
after reading Archie's explanation (Archie Lachner), I submit the
following:
	given a structure struct X {
					int a;
					int b;
					int c;
				}
	with a register pointer p of type X;

	p = p + 4 	generates

	addl	$48,reg_n,reg_n		; add decimal 48 to register
					; VAX - berkeley C compiler

and
	add	$30,reg_n		; add octal 30 (24) to register
					; 11/70 - Bell C Compiler

	As you might've guessed, reg_n is p.
	In each case, the actual value added is <size of struct> * 4.

	Thus, any fears about "p = p + n" is quite unfounded.
	In fact, K&R states that a construct p[i] is actually
	treated as p + i.

If this is still not convincing enough, c'est la vie !!

	OZ

				Ozan S. Yigit (utzoo!utcsstat!cobb)
				(utzoo!yetti!ozan)
				Dept. of Computer Science
				York University