[Linux-ha-dev] gcc: an observation

[David Lee]

On Fri, 16 Feb 2007, Lars Ellenberg wrote:

> / 2007-02-16 16:00:03 +0000
> \ David Lee:
> > This is really just an observation, not (necessarily) a request for
> > fixing a problem.  (Although if someone could say "yes, that's trivially
> > fixable by doing XYZ", that would be nice.)
> >
> > Some of our systems share an old gcc compiler, version 2.95.2, on which
> > heartbeat has always built successfully until recently.  At some point in
> > the last six months or so, something has changed to stop this.  The code
> > in question is "include/crm/crm.h", around line 225:
> >    #define crm_err(fmt, args...)     do_crm_log(LOG_ERR,     fmt, ##args)
> >
> > (and similar lines) which now expand incorrectly, leaving a trailing ","
> > in that old version of gcc.
>
> iirc, this could be fixed by an extra space...
> #define crm_err(fmt, args...)     do_crm_log(LOG_ERR, fmt , ##args)
>                                                          ^^^
> so the comma is not the last "token" but the last "word" before the ##
> i may be wrong, though...

Hey, Lars, ... excellent!

I had spotted that possibility on a GNU webpage yesterday.  I had tried it
and it seemed not work on the gcc version that I had.  (The webpage hadn't
mentioned version numbers, so I attributed the failure to my old version.)

But when your email came through, I checked again, and realised that my
earlier test had only applied that ' , ' trick to one set of macros, not
to both parts of the nested pair.

So I tried it again, and it seems to work.  My test builds on a variety of
gcc versions on a variety of Redhat (FC) and Solaris seem all OK.

I've just applied a fix to the Hg 'dev' repository.

Many thanks.

-- 

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