From: utzoo!decvax!genradbo!mitccc!zrm
Newsgroups: net.unix-wizards
Title: Re: Information on Unix/Vax peculiarities
Article-I.D.: mitccc.218
Posted: Mon Dec 13 13:55:41 1982
Received: Wed Dec 15 05:27:49 1982
References: sri-unix.4758

Aw C'mon, people. Its and pointers should be of the same size to keep
the compiler implementer sane, and has relativly little to do with code
portability. Most machines, even machines that split their arithmetic
and address registers (like the 68000) have one uniform size for
registers. Because most C compilers bring things into registers and bash
on them there, one would like the most commonplace objects to fit nicely
into these registers. Ints and pointers should be of a "natural" size.
There are enough datatypes to go around so all the other sizes can be
covered.

Code portability is achieved by guarenteeing sizes, as best as one can
in C. The most common way to do this is with defined types. In order to
bring up a program, originally on a pdp11,  on a machine with 32 bit
ints, but 16 bit shorts, you would change one line in the code from

	typedef WORD int;
to
 	typedef WORD short;

and all places where size really matters will come out the same. Instead
of flaming how about an example where it might actually be useful for
there to be 16 bit ints and 32 bit pointers?

Cheers,
Zig