Hi Guennadi, On Monday 19 September 2011 21:28:09 Guennadi Liakhovetski wrote: > Hi Laurent > > just one question: > > On Mon, 19 Sep 2011, Laurent Pinchart wrote: > > > diff --git a/drivers/media/video/mt9m032.c > > > b/drivers/media/video/mt9m032.c new file mode 100644 > > > index 0000000..8a64193 > > > --- /dev/null > > > +++ b/drivers/media/video/mt9m032.c > > > @@ -0,0 +1,814 @@ > > [snip] > > > > +static int mt9m032_read_reg(struct mt9m032 *sensor, const u8 reg) > > > > No need for the const keyword, this isn't a pointer :-) > > I was actually wondering about these: of course it's not the same as using > const for a pointer to tell the compiler, that this function will not > change caller's data. But - doesn't using const for any local variable > tell the compiler, that that _variable_ will not be modified in this > function? Are there no optimisation possibilities, arising from that?
I would expect the compiler to be smart enough to notice that the variable is never assigned. In practice, for such a small function, the generated code is identical with and without the const keyword. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
