Re: Support for multi-position electro-mechanical keylocks

[Marc Balmer <marc%msys.ch@localhost>]

Am 03.08.2009 um 16:58 schrieb Peter Seebach:

> In message <7FA34163-C54B-435C-B147-DA2BBE06F848%msys.ch@localhost>, Marc  
> Balmer writes:
> > Am 03.08.2009 um 16:23 schrieb David Holland:
> >
> > > On Mon, Aug 03, 2009 at 03:45:34AM +0000, David Holland wrote:
> > > > On Sun, Aug 02, 2009 at 11:54:09AM +0200, Marc Balmer wrote:
> > > > > While preparing a hardware workshop and playing with multi- 
> > > > > position
> > > > > keylocks, [...]
> > > > >
> > > > > +       int                     __map[GPIOLOCK_MAXPINS];
> > >
> > > Er. That was supposed to say "why the underscores?"
> >
> > They are in the original code.  So why not?
>
> As a general rule, you shouldn't prefix things with underscores in C.
> (C9x 7.1.3:  "All identifiers that begin with an underscore and
> either an uppercase letter or another underscore are always reserved
> for any use.")

The variable __map is a "hidden" variable that is not used in the  
driver itself, it rather provides the memory for the pinmap to the  
gpio subsystem, i.e. it's for private gpio(4) usage.  It is done like  
this in all GPIO drivers.

- Marc Balmer