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The performance of <algorithm>.
- From: "Richard B. Kreckel" <kreckel at ginac dot de>
- To: <libstdc++ at gcc dot gnu dot org>
- Date: Wed, 19 Nov 2003 23:06:37 +0100 (CET)
- Subject: The performance of <algorithm>.
- Reply-to: <Richard dot Kreckel at ginac dot de>
Hi,
Well, I never bought the "An Inline Function is As Fast As a Macro" rumor.
But still, an experiment using std::for_each shows rather disturbing
results. Given
struct A { virtual void someaction(); };
can anybody give an easy explanation why
for_each(av.begin(), av.end(), mem_fun(&A::something));
blows up the size of the compiled code by a factor of two compared to the
straightforward implemenation? (Even when one hacks for_each to be
inlined? (BTW, why isn't it inlined?))
Maybe this is a more general question: I recently got the impression that
it does not seem possible to code efficiently using GCC's <functional> and
<algorithm> in contradiction to what all the books seem to claim. Is that
gonna change some day?
Curious
-richy.
--
Richard B. Kreckel
<Richard.Kreckel@GiNaC.DE>
<http://www.ginac.de/~kreckel/>