Re: -Wundef in *.h [was: [PATCH v2] stat-time: silence -Wunused-parameter regression]

[Eric Blake]

On 01/04/2018 03:45 AM, Tim Rühsen wrote:
> On 01/03/2018 10:29 PM, Eric Blake wrote:
>> We still use ChangeLog-style comments in the commit message (and/or
>> ChangeLog itself) for gnulib commits; it's also nice to call out which
>> previous commit to cdefs.h already added protection for -Wundef
>> compilation.  But with those additions, I'm okay with your patch; I'll
>> wait a day or so to see if anyone else chimes in.
> 
> Added GNU style commit message, unsure what you mean with "which
>  previous commit to cdefs.h already added protection for -Wundef".
> Can't find any (from commit messages).

Here's what I did in the recent commit 3206134a:

    Commit 2c5d5587 causes warnings on non-Sun systems when compiled
    under -Wunused-parameter; we've previously tweaked code in commit
    81eb8486 to avoid such warnings.

I found those commit ids by using git gui blame.  For your patch, I note
that cdefs.h already has -Wundef protection on __GNUC__ (this is the
command I used to generate examples mentioned earlier in the thread:
 git grep '# *if.*defined \([A-Z0-9_]*\) .*\1' lib/*.h
); so I did a blame to see where that protection was first added; but it
appears that

#if defined __GNUC__ && __GNUC__ >= 2

was present in that file since its introduction in commit 38885c86, and
not something added after the fact in a later gnulib commit.

At any rate, since your commit is already applied to gnulib.git, we
don't have to worry about enhancing the commit message to include any
further git archaeology.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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