Re: [PATCH v2 1/3] units: Add SI metric prefix definitions

From: Andy Shevchenko
Date: Mon Jun 07 2021 - 11:57:20 EST


On Mon, Jun 07, 2021 at 08:43:02AM -0700, Joe Perches wrote:
> On Mon, 2021-06-07 at 18:23 +0300, Andy Shevchenko wrote:
> > Sometimes it's useful to have well-defined SI metric prefix to be used
> > to self-describe the formulas or equations.

...

> > +/* Metric prefixes in accordance with Système international (d'unités) */
> > +#define PETA 1000000000000000LL
> > +#define TERA 1000000000000LL
> > +#define GIGA 1000000000L
> > +#define MEGA 1000000L
> > +#define KILO 1000L
> > +#define HECTO 100L
> > +#define DECA 10L
> > +#define DECI 10L
> > +#define CENTI 100L
> > +#define MILLI 1000L
> > +#define MICRO 1000000L
> > +#define NANO 1000000000L
> > +#define PICO 1000000000000LL
> > +#define FEMTO 1000000000000000LL

> Somewhat surprisingly to me, this seems safe.
>
> (though I suggest using UL and ULL rather than L and LL)

Okay.

> The only use of any of these seems to be:
>
> sound/pcmcia/vx/vxp_ops.c: [VX_MICRO] = 0x0c, // MICRO
> sound/pcmcia/vx/vxp_ops.c: vx_outb(chip, MICRO, level);
> sound/pcmcia/vx/vxp_ops.c: vx_outb(chip, MICRO, vx_compute_mic_level(chip->mic_level));
>
> and these vx_outb uses are themselves macros that prepend VX_ to the 2nd arg.

Is it a real issue there?

(Yes, I saw it, but I didn't check compilation in the assumption that units.h
is not anyhow included in that file).

Okay, I have compiled it, no problems registered.

--
With Best Regards,
Andy Shevchenko