🚀 go-pugleaf

Bill McCarthy wrote:
> 
> In <313DEA09.237C@tulsa.lgc.com>,
> Glenn Carr <gcarr@tulsa.lgc.com> writes:
> 
> >We've just moved from gcc 2.6.3 to 2.7.2 and we're receiving the following new
> >warnings (when -Wall is specified)....
> >
> >warning: left-hand operand of comma expression has no effect
> >
> >When this section of code is encountered in our source files...
> >
> >static char    *rcsid = "$Id: cfgopen.c,v 1.4 1995/12/11 16:04:35 gcarr Exp $";
> >#if __GNUC__ == 2
> >#define USE(var) static void * use_##var = (&use_##var, (void *) &var)
> >USE(rcsid);
> >#endif
> 
> Isn't comma in the #define is a comma operator?  Then you are taking the
> address of use_rcsid and discarding it.  What will be returned to use_rcsid
> is the address of rcsid (a char **) cast to a (void *).

Yes, it is.  It's a trick to inhibit the gcc warning about an unused variable
for 'rcsid'.  The initialization of use_rcsid 'uses' both rcsid and 
use_rcsid.  I fixed the problem by casting the first operand of the comma
operator to void...

#define USE(var) static void * use_##var = ((void)&use_##var, (void *) &var)