Re: learning dragonfly or C...
On Fri, 12 Nov 2004 01:28:46 +0100 CET
"Jonas Sundstr闣" <jonas@kirilla.com> wrote:
> Matthew Dillon <dillon@apollo.backplane.com> wrote:
> > :> struct fubar * blah;
> > :> struct fubar *nblah;
> > :>
> > :> getmafubar(&nblah);
> > :> blah = nblah;
> ...
> > Nope. Ok, I'll tell you... it's so the compiler can
> > optimize 'blah' into a register.
>
> Cool discussion, though this a much later issue for
> most coders, let alone those just starting to learn C.
>
> Random link:
> http://c2.com/cgi/wiki?PrematureOptimization
>
> One part of programming that could use a lot more effort is writing
> readable code, so that it actually makes sense to someone not familiar
> with it. (Or one self, a week later.) Choosing descriptive names for
> variables as opposed to names 1 or 2 chars long does a lot for
> readability. (Not meant as criticism of any code shared here.)
As a general principle, I agree with this completely; apropos to the
above code, I don't think it's particularly hard to follow, but it does
suffer the danger that, if someone doesn't know why two seemingly
redundant struct fubar * variables are being used, they might be tempted
to simplify the code by "refactoring" (ugh) one of them out.
So, I'd definately prefer that this particular advanced C trick be
commented when it appears. By some amazingly fortunate stroke of luck,
the C language actually supports this comment intrinsically! To wit:
struct fubar *blah;
register struct fubar *reg_blah;
:)
-Chris
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