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From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: net.lang.c
Subject: Re: Boolean Operators Slighted in C
Message-ID: <412@brl-smoke.ARPA>
Date: Wed, 30-Apr-86 07:43:01 EDT
Article-I.D.: brl-smok.412
Posted: Wed Apr 30 07:43:01 1986
Date-Received: Sun, 4-May-86 05:34:47 EDT
References: <838@ihwpt.UUCP>
Reply-To: gwyn@brl.ARPA
Distribution: net
Organization: Ballistic Research Lab (BRL)
Lines: 27

In article <838@ihwpt.UUCP> knudsen@ihwpt.UUCP (mike knudsen) writes:
>Has anyone else noticed that Boolean types and operators
>have less than full citizenship in C?  Examples:
>...
>(3) There is no boolean data type.  No big gripe;
>lots of us say "typedef short bool" in our .h files.

Technically, there are no true Boolean data types in C.
Ints (NOT shorts) are made to serve when a Boolean would
be called for.  I have always considered this a deficiency,
but (except for getting "lint" to cooperate) it can be
remedied by the programmer being careful to keep Boolean
usages distinct from integer usages.  For example, treat
the result of a relational expression as Boolean, not as
a 1 or a 0.  I find that carefully maintaining the
distinction contributes to code correctness and
maintainability.

I generally frown on C language extension via the
preprocessor (as in a recent Byte article), but I make an
exception for Booleans.  The same standard header file
that I mentioned a few days ago (that defines "void" for
machines that don't have it, etc.) contains the following:

typedef int	bool;			/* boolean data */
#define 	false	0
#define 	true	1