Subject: Re: [Boost-bugs] [Boost C++ Libraries] #680: significantly different timer class behaviour on Win and Lin
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2007-08-28 00:17:08
#680: significantly different timer class behaviour on Win and Lin
------------------------+---------------------------------------------------
Reporter: skv | Owner: bemandawes
Type: Bugs | Status: closed
Milestone: | Component: timer
Version: None | Severity: Showstopper
Resolution: duplicate | Keywords:
------------------------+---------------------------------------------------
Changes (by bemandawes):
* status: new => closed
* resolution: None => duplicate
Old description:
> {{{
> clock() function used in implementation of
> boost::timer behaves differently on Windows (MS XP
> Pro, MSVC 7.1) and Linux (FC3, gcc 3.4.2).
>
> Windows: clock measures elapsed time (wall clock).
> And this comply with boost::timer interface
> description.
>
> Example:
> boost::timer t;
> double sec = 1;
> ::Sleep(sec*1000);
> double d = t.elapsed();
> assert(abs(d-sec) < 0.1);
>
> Linux: clock() function returnes process CPU time.
> The above code will fail.
>
> This difference makes boost::timer a bad candidate
> for cross-platform development. I can propose
> alternative implementation with simalar right
> behaviour.
>
> ------------------------------------------
> #ifndef
> _Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385uyn0v68uy
> c0n4c5
> #define
> _Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385uyn0v68uy
> c0n4c5
>
> #include <time.h>
>
> namespace Timer
> {
> /*
> Measures intervals of wall clock time, but
> not process CPU time. Resolution & accuracy depends
> on time function abilities.
> */
> class timer
> {
> public:
> // setup reference time point
> timer()
> {
> restart();
> }
>
> // reset reference time point
> void restart()
> {
> ::time(&m_ref_time);
> }
>
> // report difference between current
> time and reference point
> double elapsed() const
> {
> time_t curr_time;
> ::time(&curr_time);
> double diff = difftime
> (curr_time, m_ref_time);
> return diff;
> }
>
> // forbidden
> private:
> timer(const timer &);
> timer & operator=(const timer &);
>
> private:
> time_t m_ref_time;
> };
>
> } // namespace Timer
>
> #endif //_Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385
> uyn0v68uyc0n4c5
>
> }}}
New description:
{{{
clock() function used in implementation of
boost::timer behaves differently on Windows (MS XP
Pro, MSVC 7.1) and Linux (FC3, gcc 3.4.2).
Windows: clock measures elapsed time (wall clock).
And this comply with boost::timer interface
description.
Example:
boost::timer t;
double sec = 1;
::Sleep(sec*1000);
double d = t.elapsed();
assert(abs(d-sec) < 0.1);
Linux: clock() function returnes process CPU time.
The above code will fail.
This difference makes boost::timer a bad candidate
for cross-platform development. I can propose
alternative implementation with simalar right
behaviour.
------------------------------------------
#ifndef
_Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385uyn0v68uy
c0n4c5
#define
_Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385uyn0v68uy
c0n4c5
#include <time.h>
namespace Timer
{
/*
Measures intervals of wall clock time, but
not process CPU time. Resolution & accuracy depends
on time function abilities.
*/
class timer
{
public:
// setup reference time point
timer()
{
restart();
}
// reset reference time point
void restart()
{
::time(&m_ref_time);
}
// report difference between current
time and reference point
double elapsed() const
{
time_t curr_time;
::time(&curr_time);
double diff = difftime
(curr_time, m_ref_time);
return diff;
}
// forbidden
private:
timer(const timer &);
timer & operator=(const timer &);
private:
time_t m_ref_time;
};
} // namespace Timer
#endif //_Timer_h_dlfkgh9384ytdflg9045uhy0823475mgd385
uyn0v68uyc0n4c5
}}}
Comment:
This request has been repeated many times. The Boost.System replacement
that Philippe spoke of is now (27 Aut 2007) in the boost-sandbox. See
boost-root/libs/system/doc/timer.html.
This should be moving into the review queue in the next week or so. I'm
closing out the ticket.
Thanks,
--Beman
--
Ticket URL: <http://svn.boost.org/trac/boost/ticket/680#comment:3>
Boost C++ Libraries <http://www.boost.org/>
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