From: Alex Vinokur <alexvn AT bigfoot DOT com>
Newsgroups: comp.os.msdos.djgpp,comp.lang.c++
Subject: Re: Optimization and operator&&
Date: Wed, 05 Jun 2002 14:41:56 +0200
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Alex Vinokur wrote:

> "Heinz Ozwirk" <wansor42 AT gmx DOT de> wrote in message
> news:adin9l$s7q$00$1 AT news DOT t-online DOT com...
> > "Alex Vinokur" <alexvn AT bigfoot DOT com> wrote in message
> [snip]
> > But that doesn't answer your question, and I cannot do so. Common sense
> > suggests that optimized code should be faster than plain code and if a
> > compiler slows down a program when optimizing might be a hint that the
> > compiler does something wrong. Or the uclock() function is not the proper
> > tool for timing code.
> >
>
> Similar results have been received when using the getrusage() function
> http://www.mcsr.olemiss.edu/cgi-bin/man-cgi?getrusage+3
> and 'struct timeval ru_stime' in 'struct rusage'.

Something like :

------------------------

#include <sys/resource.h>
#include <iostream>

unsigned long get_diff_time (
 const rusage& start_time_i,
 const rusage& end_time_i
 )
{

double ret_double_value =
  (
    end_time_i.ru_utime.tv_sec
    -
    start_time_i.ru_utime.tv_sec
  )
  +
  (
    end_time_i.ru_utime.tv_usec
    -
    start_time_i.ru_utime.tv_usec
  )/ 1.0e6;

unsigned long ret_ulong_value;

  ret_ulong_value = static_cast<unsigned long>(ret_double_value * 1000000);
  return ret_ulong_value;
}


int main ()
{

  getrusage(RUSAGE_SELF, &start_time);
  // Stuff
  getrusage(RUSAGE_SELF, &end_time);
  cout << get_diff_time (start_time, end_time) << endl;

  return 0;

}

------------------------

>
>
> > Regards
> >     Heinz
> >
> >

Regards,
  ===========================
  Alex Vinokur
    mailto:alexvn AT bigfoot DOT com
    mailto:alexvn AT go DOT to
    http://up.to/alexvn
    http://go.to/alexv_math
  ===========================