Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site burl.UUCP
Path: utzoo!watmath!clyde!burl!rcj
From: rcj@burl.UUCP (R. Curtis Jackson)
Newsgroups: net.unix-wizards
Subject: long vs. int vs. short guidelines (especially for wizards!!)
Message-ID: <430@burl.UUCP>
Date: Thu, 5-Apr-84 20:04:44 EST
Article-I.D.: burl.430
Posted: Thu Apr  5 20:04:44 1984
Date-Received: Sat, 7-Apr-84 03:13:23 EST
References: <444@sri-arpa.UUCP>
Organization: AT&T Technologies; Burlington, NC
Lines: 42

Here are some guidelines on using int/short/long direct from
both past experience and the AT&T Technologies Unix/C interfacing
course I took a while back:

GUIDELINE #1:	DON'T EVER USE int.

GUIDELINE #2:	THERE IS NO GUIDELINE #2.

It is very simple -- don't worry about which type is involved; just
worry about how many bits you need.  If you are doing heavy math, you
may want to watch out for automatic conversions; they are explained
in great detail in R&K p. 184 section 6.6.  As for the reason not to
use int, here is a rundown on three computers that I can
be sure of my info on right off the bat:

	   Number of bits
	short	int	long
3B20S	16	32	32
VAX	16	32	32
PDP	16	16	32

One excellent way to do things is to head each program or major
header file (if a big software package is involved) with the
following:

typedef EIGHT	char;
typedef SIXTEEN	short;
typedef THIRTY2	long;

or something similar.  Then just tell the person porting the software
to go in and do a 30-second customization of your program(s); you
will have used your EIGHT, SIXTEEN, and THIRTY2 throughout so all
she has to change is those three lines.  I would love to see some
good portability guidelines for 'C', because I get REAL tired of
people who write code without (apparently) knowing about cpp(1),
typedef statements, make(1), header files, etc. etc.

Who, me?  Throw the first stone?  I must be a saint!!    :-)
-- 

The MAD Programmer -- 919-228-3313 (Cornet 291)
alias: Curtis Jackson	...![ floyd clyde ihnp4 mhuxv ]!burl!rcj