Re: [PATCH v6 2/3] iio: light: add support for veml6046x00 RGBIR color sensor

[Matti Vaittinen]

On 21/08/2025 21:53, Andreas Klinger wrote:
> Hi Andy,
>
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> schrieb am Do, 21. Aug 12:43:
> > > > > +	part_id = le16_to_cpu(reg);
> > > > > +	if (part_id != 0x0001)
> > > > > +		dev_info(dev, "Unknown ID %#04x\n", part_id);
> > > >
> > > > For 0 it will print 0 and not 0x0000. Is it okay?
> > >
> > > I just tried and it prints 0x00 if the part_id is 0.
> >
> > This is interesting... So it's not 0, nor 0x0000?
>
> No. It prints 0x00 on my BeagleBoneBlack with kernel 6.16.0-rc5.

I think this makes sense because of the '#' -flag. The "0x" is appended 
because of it, and this consumes 2 characters from the 4 character 
field, leaving only 2 chars left for the value.

What I find interesting is that gcc on my PC does:

        printf("%#04x\n", 0);
        printf("%#04x\n", 1);
        printf("%#04x\n", 10);
        printf("%#04x\n", 17);

0000
0x01
0x0a
0x11

gcc version 15.2.1 20250808 (Red Hat 15.2.1-1) (GCC)

It'd be nice to learn why the zero is treated differently? Andy, did you 
have some insight as you asked this?

Yours,
	-- Matti