Re: [PATCH] headers_check.pl: disallow extern's

Arnd Bergmann
2009-01-02T23:59:37Z

On Wednesday 31 December 2008, Mike Frysinger wrote:
> On Wednesday 31 December 2008 11:58:03 Arnd Bergmann wrote:
>
> > Not sure if we can detect the other form reliably from perl.
>
> yes, i already mentioned both of these issues.  that's why i suggested we
> start adding "extern" to all the headers (or at least the userspace ones).

The general trend seems to be to remove the "extern" keyword from
kernel headers, because it is not interpreted, just like the 'auto'
keyword. In fact, only few of them currently carry the extern keyword:

$ ctags -f- -R --c-kinds=p obj/usr/include/ | grep extern | wc -l
33

$ ctags -f- -R --c-kinds=p obj/usr/include/ | grep -v extern | wc -l
191

Note that this is a completely separate issue from extern variable
declarations, which should to be disallowed in any case, and are easy
to detect as they always require the extern keyword.