GNU bug report logs - #23640
25.1.50; Getting rid of compiler warnings

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Package: emacs;

Reported by: Ken Brown <kbrown <at> cornell.edu>

Date: Sat, 28 May 2016 18:41:02 UTC

Severity: normal

Found in version 25.1.50

Done: Ken Brown <kbrown <at> cornell.edu>

Bug is archived. No further changes may be made.

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Message #52 received at 23640 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: rms <at> gnu.org
Cc: 23640 <at> debbugs.gnu.org, andrewjmoreton <at> gmail.com
Subject: Re: bug#23640: 25.1.50; Getting rid of compiler warnings
Date: Wed, 1 Jun 2016 14:10:48 -0700

On 06/01/2016 01:37 PM, Richard Stallman wrote:
> A macro UNUSED_LISP could handle the first.

Yes, we could have separate macros for each data type requiring 
syntactically different initializers. Something like this, say:

    int n UNUSED_0;
    Lisp_Object obj UNUSED_Qnil;

instead of the current:

    int n IF_LINT (= 0);
    Lisp_Object obj IF_LINT (= Qnil);

We could easily change the code in that way. Is it worth the trouble?

> What is the reason for writing IF_LINT (volatile)
> instead of just volatile?

Primarily, to tell the reader that the 'volatile' is not needed for 
correctness; it's present only to pacify a buggy compiler or lint 
checker. (In this case, it pacifies GCC; see GCC bug#54561.) It's 
basically the same reason the code uses 'IF_LINT (= 0)' rather than '= 0'.
This bug report was last modified 8 years and 349 days ago.

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