On Tue, 20 Sep 2011, Laurent Pinchart wrote: > 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. Sure, but using "const" would allow the compiler to catch and complain about uses like foo(®); unless foo() is also declared as foo(const u8 *). But yes, for small obvious functions it makes no difference. > In practice, for such a small function, the generated code is > identical with and without the const keyword. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
