Re: [PATCH] CodingStyle: Expand IS_ENABLED() documentation

From: Bjorn Helgaas
Date: Tue Sep 27 2016 - 16:32:45 EST


On Tue, Sep 27, 2016 at 09:32:08PM +0200, Paul Bolle wrote:
> On Tue, 2016-09-27 at 14:08 -0500, Bjorn Helgaas wrote:
>
> > --- a/Documentation/CodingStyle
> > +++ b/Documentation/CodingStyle
>
> > +Because the compiler processes the block, you have to use an #ifdef instead
> > +of IS_ENABLED() when code inside the block references symbols that will not
> > +exist if the condition is not met.  Different CONFIG_FOO autoconf.h symbols
> > +are generated for modular Kconfig options than for builtin ones, so you
> > +need "#if defined(CONFIG_FOO) || defined(CONFIG_FOO_MODULE)"
>
> Isn't that equivalent to "#if IS_ENABLED(CONFIG_FOO)"?

Yep, I think so. Sigh. I'll look again. Maybe what's already there can't
be improved.