Re: [lm-sensors] [patch 00/36] New w83795 driver

[Guenter Roeck <guenter.roeck@ericsson.com>]

On Sat, Sep 18, 2010 at 10:16:14AM -0400, Jean Delvare wrote:
> On Sat, 18 Sep 2010 06:34:33 -0700, Guenter Roeck wrote:
> > Hi Jean,
> > On Sat, Sep 18, 2010 at 07:56:01AM -0400, Jean Delvare wrote:
> > > > +		 * But that causes lsb to be undefined across loop instances,
> > > > +		 * doesn't it, since it is only defined inside the loop ?
> > > > +		 * And what happens if an even fan does not exist
> > > > +		 * but the odd one does ?
> > > > +		 */
> > > >  		if ((i & 1) = 0 && (data->has_fan & (3 << i)))
> > > >  			lsb = w83795_read(client, W83795_REG_FAN_MIN_LSB(i));
> > > >  
> > > 
> > > I don't see any problem with lsb being undefined. lsb is always set if
> > > it is going to be needed. I also don't see any problem with odd and
> > > even fans: lsb is set if _any_ fan in a given pair is present (see the
> > > 3 << i).
> > > 
> > > If you can think of a specific scenario where it doesn't work, please
> > > let me know. The code looks good to me.
> > > 
> > Looks like lsb survives across loop instances; at least the compiler doesn't complain 
> > about it. So I guess you are right.
> 
> Of course it does. Why wouldn't it?
> 
Wrong understanding of C on my side. Still happens, as it is.
I thought the lifetime of a local variable inside a loop is only
for single instance of that loop. Apparently that is not the case.

Guenter

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