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From: crowl@cs.rochester.edu (Lawrence Crowl)
Newsgroups: comp.lang.c,comp.sys.atari.st,comp.sys.amiga
Subject: Re: 32bit = 16bit x 16bit
Message-ID: <3626@sol.ARPA>
Date: Tue, 27-Oct-87 13:53:03 EST
Article-I.D.: sol.3626
Posted: Tue Oct 27 13:53:03 1987
Date-Received: Thu, 29-Oct-87 23:46:36 EST
References: <1912@gryphon.CTS.COM> <3294@sol.ARPA> <2545@cbmvax.UUCP> <2565@cbmvax.UUCP> <2262@sfsup.UUCP>
Reply-To: crowl@cs.rochester.edu (Lawrence Crowl)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 55
Xref: mnetor comp.lang.c:5172 comp.sys.atari.st:5965 comp.sys.amiga:10031

In article <2262@sfsup.UUCP> mpl@sfsup.UUCP (M.P.Lindner) writes:
>3. as for the people who say "Never use the basic types", I say the following:
>	1. use "char" to mean a character or a byte (guaranteed in K&R)

Use char to mean a character.  Use "typedef char applicationtype" when the best
implementation for the intended use happens to be a char on your machine.  My
six bit char may not give the range you assumed because of your chars are
twelve bits.

>	2. use short for a small integer

Use "typedef short applicationtype" when the best implementation for the
intended use happens to be a short on your machine.  My short may be longer
than your short.  This way I only have to change the implementation in one
place.

>	3. use int where the size doesn't matter

Use "typedef int applicationtype" when the implementation for the intended use
does not matter significantly.  Let's hope my ints are at least as large as
you assume.

>	4. use long where you need a long (ie in interfacing to the OS, etc.)

Use a crowbar where you need a crowbar?  Use "typedef long systemtype" when the
implementation for the system type is a long.  When porting, changing the
types passed to system routines in one place can reduce hassle considerably.

>	5. use pointers with care

Amen.

>	6. use void where you mean void (either the compiler handles it or
>	   it doesn't - if it does, great, if it doesn't, try "cc -Dvoid=int"
>	   but don't go changing the input language because you have a bad
>	   compiler.

Agreed.

>	7. NEVER NEVER NEVER! use LONG, ULONG, VOID, etc.
>	   if you're using ULONG because you want an unsigned 32 bit integer
>	   try using
>		typedef unsigned long	uint32;
>		typedef long	int32;
>	  so someone can try to figure out what bizzare thing you were trying
>	  to do.

Use "typedef BASIC_TYPE APPLICATION_TYPE /* required range is a..b */".  This
documents the program's needs and allows people porting the program to identify
exactly what changes need to be made.

-- 
  Lawrence Crowl		716-275-9499	University of Rochester
		      crowl@cs.rochester.edu	Computer Science Department
...!{allegra,decvax,rutgers}!rochester!crowl	Rochester, New York,  14627