Re: Don't return void types from void functions.

Re: Don't return void types from void functions.

[Jeff Garzik]

Linux Kernel Mailing List wrote:
> diff -Nru a/drivers/net/tokenring/olympic.c b/drivers/net/tokenring/olympic.c
> --- a/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00
> +++ b/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00
> @@ -1806,7 +1806,7 @@
>  
>  static void __exit olympic_pci_cleanup(void)
>  {
> -	return pci_unregister_driver(&olympic_driver) ; 
> +	pci_unregister_driver(&olympic_driver) ; 
>  }	


Can we make gcc error out when it finds this?

	Jeff

Re: Don't return void types from void functions.

[Denis Vlasenko]

On Wednesday 26 May 2004 09:28, Jeff Garzik wrote:
> Linux Kernel Mailing List wrote:
> > diff -Nru a/drivers/net/tokenring/olympic.c
> > b/drivers/net/tokenring/olympic.c ---
> > a/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00 +++
> > b/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00 @@ -1806,7
> > +1806,7 @@
> >
> >  static void __exit olympic_pci_cleanup(void)
> >  {
> > -	return pci_unregister_driver(&olympic_driver) ;
> > +	pci_unregister_driver(&olympic_driver) ;
> >  }
>
> Can we make gcc error out when it finds this?

AFAIK new C++ standard allows this syntax.

typedef int opaque;

opaque f();
opaque g() { return f(); }

Now imagine we need to change
-typedef int opaque;
+typedef void opaque;
-- 
vda

Re: Don't return void types from void functions.

[Paweł Sikora]

On Wednesday 26 of May 2004 10:38, Denis Vlasenko wrote:
> On Wednesday 26 May 2004 09:28, Jeff Garzik wrote:
> > Linux Kernel Mailing List wrote:
> > > diff -Nru a/drivers/net/tokenring/olympic.c
> > > b/drivers/net/tokenring/olympic.c ---
> > > a/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00 +++
> > > b/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00 @@ -1806,7
> > > +1806,7 @@
> > >
> > >  static void __exit olympic_pci_cleanup(void)
> > >  {
> > > -	return pci_unregister_driver(&olympic_driver) ;
> > > +	pci_unregister_driver(&olympic_driver) ;
> > >  }
> >
> > Can we make gcc error out when it finds this?
>
> AFAIK new C++ standard allows this syntax.
>
> typedef int opaque;
>
> opaque f();
> opaque g() { return f(); }
>
> Now imagine we need to change
> -typedef int opaque;
> +typedef void opaque;

strict ISO C++ - yes,
strict ISO C - no.

# g++ -Wall -s -c void_ret.cpp -pedantic-errors

# gcc -Wall -s -c void_ret.c -pedantic-errors
void_ret.c: In function `g':
void_ret.c:4: error: `return' with a value, in function returning void

# gcc --version
gcc (GCC) 3.4.0 SSP (PLD Linux)
(...)

-- 
If you think of MS-DOS as mono, and Windows as stereo,
  then Linux is Dolby Digital and all the music is free...

Re: Don't return void types from void functions.

[H. Peter Anvin]

Followup to:  <40B43913.7010207@pobox.com>
By author:    Jeff Garzik <jgarzik@pobox.com>
In newsgroup: linux.dev.kernel
>
> Linux Kernel Mailing List wrote:
> > diff -Nru a/drivers/net/tokenring/olympic.c b/drivers/net/tokenring/olympic.c
> > --- a/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00
> > +++ b/drivers/net/tokenring/olympic.c	2004-05-25 23:06:49 -07:00
> > @@ -1806,7 +1806,7 @@
> >  
> >  static void __exit olympic_pci_cleanup(void)
> >  {
> > -	return pci_unregister_driver(&olympic_driver) ; 
> > +	pci_unregister_driver(&olympic_driver) ; 
> >  }	
> 
> 
> Can we make gcc error out when it finds this?
> 

What's wrong with it?  Seriously... "return foo();" is the closest
thing to a tailcall syntax as C/C++ has, and I've always considered it
a Total Fscking Pain in The Ass[TM] that it somehow thinks functions
returning void should have a different syntax than all other functions.

	-hpa