Re: [gentoo-user] Re: Plasma-runtime compilation problems

[Michael Schreckenbauer <grimlog@gmx.de>]

Hi Walt,

Am Mittwoch, 10. August 2011, 16:16:50 schrieb walt:
> On 08/10/2011 03:04 PM, Michael Schreckenbauer wrote:
> > Hi,
> > 
> > Am Mittwoch, 10. August 2011, 14:40:31 schrieb walt:
> >> On 08/09/2011 08:34 PM, Jeff Cranmer wrote:
> >>> Hi all,
> >>> 
> >>> I'm trying to upgrade kde from 4.4 to 4.6, and I've run into a
> >>> problem.
> >>> 
> >>> Plasma-runtime-4.6.3 is failing.  The error appears to be
> >>> redefinition of 'struct QMetaTypeID<Plasma::Service*>'
> >> 
> >> I don't use kde so I can't be specific, but usually a redefinition is
> >> just a warning -- unless the package is compiled with the -Wall flag
> >> or
> >> equivalent.
> 
> (Of course I meant -Werror, sorry.)

no prob.
 
> > No, this is plain wrong. Redefinition of a struct is an error in C and
> > C++
> > 
> > ~$cat foo.c
> > struct foo {
> > 
> >         int i;
> > 
> > };
> > 
> > struct foo {
> > 
> >         char* v;
> > 
> > };
> > 
> > ~$gcc foo.c -o foo
> > foo.c:5:8: error: redefinition of 'struct foo'
> > foo.c:1:8: note: originally defined here
> 
> Hm.  I know I've seen compiler redefinition messages thousands of times
> over the years.  Is it really possible that all of those thousands were
> errors instead of warnings?  If that's true then I've wasted a lot more
> time tracking them down than I care to think about :)

struct redefinition is always an error.
Maybe what you saw as a warning was some kind of macro redefined.

~ $ cat bar.c
#define BAR 0
#define BAR 1

int main()
{
}

~$gcc bar.c -o bar
bar.c:2:0: warning: "BAR" redefined
bar.c:1:0: note: this is the location of the previous definition

Note the different wording in the message.

Regards,
Michael