Re: __dead functions

["Valeriy E. Ushakov" <uwe%stderr.spb.ru@localhost>]

On Fri, Jul 18, 2008 at 12:01:09 -0400, Greg A. Woods; Planix, Inc. wrote:

> >+#if __GNUC_PREREQ__(4, 3)
> >+#define __NOTREACHED for (;;) continue
> >+#else
> >+#define __NOTREACHED
> >+#endif
> 
> I think inventing extra redundant identifiers like this one, even if  
> prefixed by "__" is unnecessary.
> 
> Indeed gcc doesn't understand a NOTREACHED comment, that's a lint  
> directive of course and it seems, unfortunately, that lint has fallen  
> out of favour in NetBSD.

How does use or disuse of lint changes the fact that *a different
tool*, gcc in this case, complains that some code is (not) reached
when gcc thinks it should (not) be.

Actually we can arrange for lint's /* NOTREACHED */ comment to appear
at the end of that macro so that one macro covers "notreached"
semantics for all the tools we use.  Using an example from my previous
mail:

#ifdef __lint__
#define __MARK_NOTREACHED /* NOTREACHED */
#else /* !__lint__ */
#if __GNUC_PREREQ__(4, 0)
#define __MARK_NOTREACHED for (;;) continue
#else
#define __MARK_NOTREACHED do {} while (/* CONSTCOND */ 0)
#endif
#endif /* !__lint__ */

then we can have a single

    __NOTREACHED;

statement in the code that will cover lint, gcc, and anything else we
might need to use in the future.


SY, Uwe
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