On Wed, 5 Jul 2006 16:35:30 -0700 Andrew Morton wrote:
> On Wed, 5 Jul 2006 16:24:25 -0700
> "Randy.Dunlap" <[email protected]> wrote:
>
> > On Mon, 03 Jul 2006 19:27:07 +0200 Arjan van de Ven wrote:
> >
> > > On Mon, 2006-07-03 at 10:13 -0700, Linus Torvalds wrote:
> > > > #ifndef xyzzy
> > > > #define zyzzy() /* empty */
> > > > #endif
> > > >
> > >
> > > now if you write it as
> > >
> > > #define zyzzy() do { ; } while (0)
> > >
> > > it even works in a
> > >
> > > if (foo())
> > > zyzzy();
> > > bar();
> > >
> > > scenario
> > >
> > > (I know you know that, just pointing that out before people copy your
> > > example :-)
> >
> > OK, I'll bite. What part of Linus's macro doesn't work.
> > I compiled your foo/zyzzy/bar example with both his "empty"
> > macro and the do-while macro. Same code produced both ways,
> > no compile warnings/errors.
> >
>
> if (foo())
> ;
>
> will generate `warning: empty body in an if-statement' when compiled with -W.
>
> We go round this loop regularly. Maybe someone should write it up. Meanwhile,
> use do{}while(0) and be happy and secure.
Thanks, I was missing the -W.
or I should read the kernelnewbies FAQ :)
http://kernelnewbies.org/FAQ/DoWhile0
---
~Randy
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