From: Alan <illeman AT interlog DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: CLOCKS_PER_SEC in DJGPP
Date: Fri, 06 Aug 1999 06:34:40 -0400
Organization: Interlog Internet Services
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Go with 18.2/sec.
When you ulong overflows, inc another ulong.

Michal Strelec wrote:
> 
> Hi,
> In my program I use function clock(), whitch returns number of timer ticks
> from the begining of program.
> But how many ticks timer do in a seconds in real?
> I thought that 18.2, but in source code of communication package (pmcomm) I
> found
> ****************************************
>    Function: TIMERHandler
>    Description:
>      Invoked 19.5 times per second.
> ****************************************
> And in DjGpp Timer.h I also found
> #define CLOCKS_PER_SEC 91
> In BC31 timer.h
> #define CLOCKS_PER_SEC 18.2
> 
> So I'm a quit confused and I don't know how many times per sec timer runs.
> 
> Is it compiler dependece (clock function in djgpp vs. bc)?
> 
> That one problem, but here comes second:
> On i386 the maximum allowed type of variable is ulong, isn't it?
> But function clock returns long. So maximum number is 2147483647L. If I
> transfer it to days (using 18.2 ticks per sec ) I get 1365 day = 3.7 year
> (aproximately). But may program may run more then 3.7 year (in one run)
> counter of this type may overflow.
> Is any possibility how to englare this range?