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From:	olly AT mantis DOT co DOT uk (Olly Betts)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: clock() unit ?
Date:	12 Oct 1995 18:21:13 +0100
Organization:	techn-ol-ogy
Lines:	33
References:	<45iniu$6c5 AT news DOT cea DOT fr>
Nntp-Posting-Host:	sunforest.mantis.co.uk
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway:	from newsgroup comp.os.msdos.djgpp

In article <45iniu$6c5 AT news DOT cea DOT fr>,
Eric NICOLAS <nicolas AT dsys DOT ceng DOT cea DOT fr> wrote:
>ANSI C tell that there should be a CLK_TCK constant which says that, but I
>found
>somewhere in djgpp .H a #define CLK_TCK 100, and when trying that it is
>obvious
>that this is wrong.
>
>In fact, it seems that there are about 1 million clock() units per seconds.
>But
>what is the real value ?

In DJGPP v1.12m4, time.h says: #define CLOCKS_PER_SEC 1000000
and limits.h says: #define CLK_TCK 100

I *think* that CLOCKS_PER_SEC is an old alternative name for CLK_TCK, so they
should be the same if both are defined.  I may be wrong though.

Anyway, coupled with what you say, it looks like the real value is exactly
1000000, and that the CLK_TCK in limits.h is bogus.

In DJGPP v2-beta3, time.h says: #definde CLOCKS_PER_SEC 91
and also: #define CLK_TCK CLOCKS_PER_SEC

So they are the same there.  A comment says:

/* 65536(tics/hour) / 3600(sec/hour) * 5(scale) = 91.02
   The 5 is to make it a whole number (18.2*5=91) so that
   floating point ops aren't required to use it. */

Olly
-- 
cool wet grass  cool wet grass  cool wet grass  cool wet grass  cool wet grass

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