Re: 2.2.18 signal.h

From: Michael Meissner (meissner@spectacle-pond.org)
Date: Fri Dec 15 2000 - 15:15:03 EST


On Fri, Dec 15, 2000 at 04:06:36PM -0300, Horst von Brand wrote:
> "Richard B. Johnson" <root@chaos.analogic.com> said:
>
> [...]
>
> > Both examples allow an extern declaration inside a function scope
> > which is also contrary to any (even old) 'C' standards. 'extern'
> > is always file scope, there's no way to make it otherwise.
>
> AFAIR (rather dimly... no K&R at hand here) if you have an extern
> declaration inside a block, it will be visible only within that block. The
> object itself certainly is file scope (or larger).

Old K&R allowed the following:

        foo(){
          extern int a;

          a = 1;
        }

        bar(){
          a = 2;
        }

Ie, compiler put the definition for a in the file scope symbol table, and not
the current block's. The above example is illegal in ISO C.

-- 
Michael Meissner, Red Hat, Inc.  (GCC group)
PMB 198, 174 Littleton Road #3, Westford, Massachusetts 01886, USA
Work:	  meissner@redhat.com		phone: +1 978-486-9304
Non-work: meissner@spectacle-pond.org	fax:   +1 978-692-4482
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