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From: diamond@jit345.swstokyo.dec.com (Norman Diamond)
Newsgroups: comp.std.c
Subject: Re: #error
Message-ID: <1991Apr24.004437.26993@tkou02.enet.dec.com>
Date: 24 Apr 91 00:44:37 GMT
References: <14793@darkstar.ucsc.edu> <687@taumet.com>
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Reply-To: diamond@jit345.enet@tkou02.enet.dec.com (Norman Diamond)
Organization: Digital Equipment Corporation Japan , Tokyo
Lines: 34

In article <687@taumet.com> steve@taumet.com (Stephen Clamage) writes:
>daniel@terra.ucsc.edu (Daniel Edelson) writes:
>>There is no constraint to the effect:
>>	``The #error directive shall not be present.''
>>Therefore, a strictly conforming program may contain #error.
>
>The Rationale states, "It is the intent of the Committee, however,
>that translation cease immediately upon encountering this directive..."

Sigh, in giving my previous answer, I neglected to RTFR again.
Nonetheless, my previous answer (and Mr. Clamage's) are correct according
to the wording of TFS.

>The problem is that there is no way to put this language into the
>standard itself.

There sure is.  To modify Mr. Edelson's hypothesis appropriately:
    ``The #error directive shall not be present except in groups that
      are skipped under control of conditional inclusion (section 3.8.1)."

In fact, such wording would mean exactly what is desired.  The programmer
would really have an illegal program.  After all, the programmer's
purpose in using #error was so that the programmer could tell itself
that it made an illegal program.  (The programmer in this case may be a
collection of persons.)

However, TFS did not include such a clean statement of the committee's
intention.  The combination of TFS and TFR suggests that their intention
is for implementations to play low and dirty games with implementation
limits.  This is unfortunate.  It actively discourages the idea of
Quality of Implementation, instead of being neutral on such ideas.
--
Norman Diamond       diamond@tkov50.enet.dec.com
If this were the company's opinion, I wouldn't be allowed to post it.