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From: dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi)
Newsgroups: comp.std.c
Subject: Re: #pragma
Message-ID: <2772@cirrusl.UUCP>
Date: 5 Dec 90 19:42:15 GMT
References: <9012050330.AA04857@decpa.pa.dec.com>
Sender: news@cirrusl.UUCP
Organization: Cirrus Logic Inc.
Lines: 26

In <9012050330.AA04857@decpa.pa.dec.com> diamond@tkou02.enet.dec.com
("diamond@tkovoa") writes:

>In that case, why should unrecognized #pragmas be ignored?

A minor mistake.

Pragmas allow one to escape from the confines of the standard.  Such
escapes should always be done under the full control of the user.  A
good way to implement pragmas is to require that all pragmas that will
be recognized by a compiler be listed in a file, and any pragma not in
that file result in a warning.  This will minimize the probability 
that a switch in compilers, or a revision in the names of pragmas
interpreted by a compiler, won't cause surprises.

The current situation, such that some pragmas are silently obeyed,
while others are silently ignored, is a disaster waiting to happen.

    /* The "unroll-loop" pragma force loop unrolling, so our process
    will react well within the 0.5 milliseconds needed to avoid a
    nuclear explosion. */

    #pragma  unrolll_loop  /* Darn!  Got to get that keybounce fixed */
--
Rahul Dhesi <dhesi%cirrusl@oliveb.ATC.olivetti.com>
UUCP:  oliveb!cirrusl!dhesi