Re: Missing "var is used uninitialized" warning?

[Georg-Johann Lay <avr at gjlay dot de>]

Jonathan Wakely schrieb:
> On 17 September 2011 21:42, Georg-Johann Lay wrote:
>
> > Jonathan Wakely schrieb:
> >
> > > On 17 September 2011 21:32, Georg-Johann Lay wrote:
> > >
> > >
> > > > Hi, compiled with -Wall -Wextra the wollowing lines don't complain about
> > > > a
> > > > being used uninitialized.  Tried with 4.5 and 4.6.  Am I missing
> > > > something?
> > > >
> > > > int func (void)
> > > > {
> > > > int a = a;
> > > >
> > > > return a;
> > > > }
> > >
> > > Yes, you're missing -Winit-self
> >
> > Thanks.
> >
> > Confusing... extra option for that?
>
> Maybe, but it's documented, so that makes it ok!
>
> > The message with -Wuninitialized -Winit-self is
> > warning: 'a' is used uninitialized in this function [-Wuninitialized]
> >
> > Is there a special reason why this is not part of Wall or Wextra?
>
> Initialising a variable with itself is a GNU extension, used to
> suppress warnings about uninitialised variables when you *really*
> don't want to initialise a variable and don't want a warning either.

Thanks for the explanation, now I understand it.

> Personally I think it's an abomination :)