Re: [PATCH] iio: adc: ad_sigma_delta.c: Cleaning up uninitialized variables

[Lars-Peter Clausen]

On 06/01/2014 01:51 PM, Rickard Strandqvist wrote:
> Hi
>
> Believe it reacted to the code below.
>
> If raw_sample = 0 is the correct starting value, I am not sure. But
> leaving it uninitialized, I think is the worst choice.
>
>
>      if (ret < 0)
>          goto out;
>
>      ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
>          DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
>          &raw_sample);
> ....
> out:
> ....

you skipped the:

    if (ret)
        return ret;

that is here.

>      sample = raw_sample >> chan->scan_type.shift;

The code is a bit confusing and it is understandable that a static checker 
might generate a false positive. The fix though is not to silence the false 
positive as this will hide actual problems if they should come up by future 
modifications of the code.

> Best regards
> Rickard Strandqvist
>
>
> 2014-06-01 11:15 GMT+02:00 Lars-Peter Clausen <lars@xxxxxxxxxx>:
> > On 06/01/2014 01:11 AM, Rickard Strandqvist wrote:
> > > There is a risk that the variable will be used without being initialized.
> > >
> > > This was largely found by using a static code analysis program called
> > > cppcheck.
> >
> >
> > This looks like a false positive. And if it was not a false positive the
> > correct fix certainly is not to initialize the variable to some random value
> > to silence the warning.
> >
> > - Lars

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