on Wed Nov 19 2008, Eric Niebler <eric-AT-boost-consulting.com> wrote:
g++ -O3 -I../../boost_1_37_0 foreach_benchmark.cpp -o foreach_benchmark Iterator accumulate took 0.09 seconds. Pointer accumulate took 0.09 seconds. Iterator for loop took 0.09 seconds. Pointer for loop took 0.09 seconds. Index for loop took 0.09 seconds. Index for_each took 0.09 seconds. Pointer for_each took 0.09 seconds. BOOST_FOREACH took 0.09 seconds. std::for_each took 0.09 seconds.
That looks better. Thanks. So for libstdc++ at least, std::for_each is no faster. I just checked and it does not do loop unrolling, at least for 4.3.0, so that's not surprising.
I guess not. If they care enough to find out, someone should compare std::find with an equivalent FOREACH loop on a random access range. -- Dave Abrahams BoostPro Computing http://www.boostpro.com