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Message-ID: <1413402764.7484.10.camel@perches.com>
Subject: Re: [PATCH 2/3] checkpatch: Add error on use of attribute((weak))
 or __weak
From: Joe Perches <joe@perches.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Whitcroft <apw@canonical.com>, linux-kernel@vger.kernel.org
Date: Wed, 15 Oct 2014 12:52:44 -0700
In-Reply-To: <20141015125000.44353284288395e216659953@linux-foundation.org>
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On Wed, 2014-10-15 at 12:50 -0700, Andrew Morton wrote:
> On Wed, 15 Oct 2014 12:45:48 -0700 Joe Perches <joe@perches.com> wrote:
> 
> > On Wed, 2014-10-15 at 12:42 -0700, Andrew Morton wrote:
> > > On Wed, 15 Oct 2014 12:32:08 -0700 Joe Perches <joe@perches.com> wrote:
> > > 
> > > > Using weak can have unintended link defects.
> > > > Emit an error on its use.
> > > 
> > > Well, we don't want a warning about use of __weak in function
> > > definitions.  Only in declarations.
> > 
> > Why is that?
> 
> Because the problem we're trying to detect is when __weak is used on a
> declaration.
> 
> This is OK:
> 
> foo.h:
> extern int foo(void);
> foo.c:
> int __weak foo(void)
> {
> 	...
> }
> 
> But this is not OK:
> 
> foo.h:
> extern __weak int foo(void);
> foo.c:
> int __weak foo(void)
> {
> 	...
> }
> 

And this?

foo.c:

extern __weak int foo(void);

int __weak foo(void)
{
}