Re: [PATCH -next] nfs: fix ISO C90 warning

Thomas Gleixner
2009-12-16T22:58:59Z

On Wed, 16 Dec 2009, Randy Dunlap wrote:
> On Wed, 16 Dec 2009 17:40:19 -0500 Trond Myklebust wrote:
>
> > On Wed, 2009-12-16 at 14:23 -0800, Randy Dunlap wrote:
> > > From: Randy Dunlap <randy.dunlap@oracle.com>
> > >
> > > Fix gcc ISO C90 warning:
> > >
> > > fs/nfs/callback.c:356: warning: ISO C90 forbids mixed declarations and code
> > >
> > > Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
> > > ---
> > > fs/nfs/callback.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > --- linux-next-20091215.orig/fs/nfs/callback.c
> > > +++ linux-next-20091215/fs/nfs/callback.c
> > > @@ -352,8 +352,8 @@ static int check_gss_callback_principal(
> > > static int nfs_callback_authenticate(struct svc_rqst *rqstp)
> > > {
> > > struct nfs_client *clp;
> > > - RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
> > > int ret = SVC_OK;
> > > + RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
> > >
> >
> > What version of gcc is giving rise to this warning?
>
> > gcc --version
> gcc (GCC) 4.2.1 (SUSE Linux)
>
> > RPC_IFDEBUG is a macro that either evaluates to its argument, or to
> > nothing, depending on whether or not RPC_DEBUG is defined or not. In
> > neither case should it evaluate to anything illegal under C90 rules
> > afaics.
>
> Yep. Odd warning.

Not really. If the debug macro evaluates to nothing then you have:

struct nfs_client *clp;
;
int ret = SVC_OK;

So you have a stray semicolon, which is interpreted as an empty code
line. That qualifies for the mixed declaration and code case :)

I know it's nitpicking, but ...

Thanks,

tglx