Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!sdd.hp.com!samsung!uunet!metaware!johnv
From: johnv@metaware.metaware.com (John Vinopal)
Newsgroups: comp.unix.internals
Subject: Re: Can Unix sleep in terms of mili/micro?
Message-ID: <595@metaware.metaware.com>
Date: 13 Sep 90 18:56:42 GMT
References: <24437@adm.BRL.MIL> <84@dlss2.UUCP> <MUTCHLER.90Sep11140510@zule.EBay.Sun>
Reply-To: johnv@metaware.COM (John Vinopal)
Distribution: usa
Organization: Metaware Incorporated, Santa Cruz, CA
Lines: 48

I seem to recall mutchler@zule.EBay.Sun (Dan Mutchler) saying:
 >   james@dlss2.UUCP (James Cummings) writes:
 >   In article <24437@adm.BRL.MIL> TAYBENGH%NUSDISCS.BITNET writes:
 >   >        Can Unix sleep in terms of mili or mirco second? I am aware that
 >   >sleep() can only sleep in terms of second. Please specify the Unix Dialect
 >   >when u reply. Thanks.
 >
 >   main()
 >   {
 >	   sleep_less_than_sec(25);
 >	   exit(0);
 >   }
 >
 >   sleep_less_than_sec(x)
 >   int x;
 >   {
 >	   int i;
 >
 >	   for (i = 0;i <= x;i++)
 >		   ;
 >   }
 >
 >	   I'd think that would give you approx. 25 clock cycles, dependent on
 >   the machine, the load on the machine, etc.
 
You assume that you have a remarkably dumb compiler.  How is that code any
different to an optimizing compiler than say:

	#define DEBUG 0
	foobar(int x)
	{
		int i;

		for (i = 0; i <= x; i++)
			if ( DEBUG ) {
				crash_n_burn();
			}
	}

You wouldn't want THAT code stuck in your executable now would you?
Both come out to be NULL and both should be removed!  Optimize, optimize,
optimize!

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