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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: CLOCKS_PER_SEC |
| Date | 2016-10-14 08:41 -0700 |
| Organization | None to speak of |
| Message-ID | <lnwphbhran.fsf@kst-u.example.com> (permalink) |
| References | <nto3cm$ps$1@dont-email.me> <20161014162129.223274fe7ba3d5b06850f0e1@g{oogle}mail.com> |
Anton Shepelev <anton.txt@g{oogle}mail.com> writes:
> BartC:
>
>>CLOCKS_PER_SEC determines how the result of the
>>clock() function is interpreted.
>>
>>But it seems to be defined as macro in time.h.
>>
>>Any ideas on how to determine that value when call-
>>ing clock() as foreign function from another lan-
>>guage? I want to avoid OS-specific functions unless
>>they are available on both Windows and Linux.
>>
>>(At the moment, CLOCKS_PER_SEC seems to be usually
>>1000 on Windows and 1000000 on Linux. I suppose I
>>could detect abnormally large values of clock() and
>>infer it that way, but I think there will be some
>>overlap in the set of valid results.)
>
> Estimate its value using the native time-measuring
> functions! I had to do that in my innovative snake
> game for MS-DOS when I wrote it in Turbo Pascal,
> whose delay procedure took a value in units the val-
> ue whereof depended on the machine speed, so that
> every game would start with a time-calibration loop.
That would be difficult to do accurately. The clock() function measures
CPU time, not real time. You'd have to execute a loop that consumes a
known amount of CPU time and compare that to the values returned by
clock() before and after the loop.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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CLOCKS_PER_SEC BartC <bc@freeuk.com> - 2016-10-13 14:49 +0100
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-13 08:57 -0700
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-13 09:07 -0700
Re: CLOCKS_PER_SEC BartC <bc@freeuk.com> - 2016-10-13 23:18 +0100
Re: CLOCKS_PER_SEC BartC <bc@freeuk.com> - 2016-10-13 23:30 +0100
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-13 16:27 -0700
Re: CLOCKS_PER_SEC raltbos@xs4all.nl (Richard Bos) - 2016-10-16 10:02 +0000
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-16 11:32 -0700
Re: CLOCKS_PER_SEC Lowell Gilbert <lgusenet@be-well.ilk.org> - 2016-10-13 12:19 -0400
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-13 11:29 -0700
Re: CLOCKS_PER_SEC Lowell Gilbert <lgusenet@be-well.ilk.org> - 2016-10-13 14:39 -0400
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-13 12:03 -0700
Re: CLOCKS_PER_SEC supercat@casperkitty.com - 2016-10-14 07:47 -0700
Re: CLOCKS_PER_SEC Anton Shepelev <anton.txt@g{oogle}mail.com> - 2016-10-14 16:21 +0300
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-14 08:41 -0700
Re: CLOCKS_PER_SEC Anton Shepelev <anton.txt@g{oogle}mail.com> - 2016-10-14 18:56 +0300
Re: CLOCKS_PER_SEC Barry Schwarz <schwarzb@dqel.com> - 2016-10-14 09:49 -0700
Re: CLOCKS_PER_SEC Keith Thompson <kst-u@mib.org> - 2016-10-14 11:14 -0700
Re: CLOCKS_PER_SEC supercat@casperkitty.com - 2016-10-14 11:32 -0700
Re: CLOCKS_PER_SEC Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-14 11:56 -0400
Re: CLOCKS_PER_SEC Anton Shepelev <anton.txt@g{oogle}mail.com> - 2016-10-14 19:53 +0300
Re: CLOCKS_PER_SEC supercat@casperkitty.com - 2016-10-14 09:57 -0700
Re: CLOCKS_PER_SEC BartC <bc@freeuk.com> - 2016-10-14 18:18 +0100
Re: CLOCKS_PER_SEC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-10-16 02:55 -0700
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