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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.c
Subject: Re: TRUE and FALSE
Message-ID: <23970:Sep505:16:2390@kramden.acf.nyu.edu>
Date: 5 Sep 90 05:16:23 GMT
References: <5398@harrier.ukc.ac.uk>
Organization: IR
Lines: 20

In article <5398@harrier.ukc.ac.uk> mtr@ukc.ac.uk (M.T.Russell) writes:
> To the people complaining about `if (x == TRUE)': YOU ONLY USE `TRUE' AND
> `FALSE' FOR ASSIGNMENT AND PARAMETER PASSING.  It's a fairly simple rule.

It is wise to take advantage of the language's syntax to remind the
programmer of this at every turn. If I were really desperate for this
type:

typedef struct { int truth; } truefalse;
#define set_true(b) ((void) ((b)->true = 1))
#define set_false(b) ((void) ((b)->true = 0))
#define is_true(b) ((b).true)

Usage: truefalse flagfoo; set_true(&flagfoo); if (is_true(flagfoo)) ...

Somehow in real programs I've never had trouble with declaring variables
flagthis, flagthat, flagtheotherthing. The ``flag'' alerts the reader.
Flags are multi-valued when I need to express different shades of truth.

---Dan