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From: gwyn@brl-smoke.UUCP
Newsgroups: comp.lang.c
Subject: Re: enum
Message-ID: <6505@brl-smoke.ARPA>
Date: Sat, 3-Oct-87 19:54:57 EDT
Article-I.D.: brl-smok.6505
Posted: Sat Oct  3 19:54:57 1987
Date-Received: Sun, 4-Oct-87 07:05:08 EDT
References: <1177@laidbak.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 13

In article <1177@laidbak.UUCP> daveb@laidbak.UUCP (Dave Burton) writes:
>	enum { A, B, C } varA, varB;
>	printf("varA  < varB is %c\n", varA  < varB ? 'T' : 'F');
>"enum.c", line 12: illegal comparison of enums

For a while, some C compilers attempted to make enums act like a "set"
type, and in the absence of ordering (PRED, SUCC operators), inequality
comparison was in general ill-defined.

ANSI C intends to have enums act much more like integers, the way older
C compilers had them, so (I think) the inequality test would work.
This may seem a step backward, but there is existing code that depends
on int-like behavior from enums.