Re: checkpatch, a patch checking script.

Geert Uytterhoeven
2007-05-02T19:55:22Z

On Wed, 2 May 2007, Andrew Morton wrote:
> On Wed, 2 May 2007 17:32:49 +0200 (CEST)
> Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> wrote:
>
> > On Wed, 2 May 2007, Christoph Hellwig wrote:
> > > On Wed, May 02, 2007 at 04:28:27PM +0200, Geert Uytterhoeven wrote:
> > > > - Check for GNU extension __FUNCTION__
> > >
> > > __FUNCTION__ is prefered over __func__
> >
> > Is there a reason for that?
> > - __FUNCTION__ is a GNU extension
> > - __func__ is C99
> > - __func__ is shorter to type ;-)
> >
>
> In that case we should use __func__.
>
> But we discussed this at some length 3-4 years ago and decided to use
> __FUNCTION__. I don't remember why. Perhaps problems with gcc support for
> __func__?

I tried gcc 2.95/3.2/3.3/3.4/4.0/4.1, they all recognize __func__ and
__FUNCTION__, like in e.g. printf("%s", __func__);

> (It could have been that compile-time string concatenation was involved:
>
>
> printf("xxx" __FILE__); /* works */
> printf("xxx" __FUNCTION__); /* doesn't */
>
> Or not.)

Yep, when trying concatenation, I got:
- 2.95: works fine
- 3.2:
syntax error before "__func__"
warning: concatenation of string literals with __FUNCTION__ is deprecated
- 3.3:
error: syntax error before "__func__"
warning: concatenation of string literals with __FUNCTION__ is deprecated
- 3.4/4.0:
error: syntax error before "__func__"
error: syntax error before "__FUNCTION__"
- 4.1:
error: expected ')' before '__func__'
error: expected ')' before '__FUNCTION__'

Hence gcc 3.2 and up treat __func__ like the a variable, as per C99, while
__FUNCTION__ has been moving from a virtual preprocessor definition in 2.95 to
a variable, like __func__.

So in the end it doesn't matter, as concatenation has been fixed in the Linux
source tree anyway.

Gr{oetje,eeting}s,

Geert

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Geert Uytterhoeven -- Sony Network and Software Technology Center Europe (NSCE)
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