Date:	Sun, 13 Oct 2002 07:58:55 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	Leonid Pauzner <uue AT pauzner DOT dnttm DOT ru>
cc:	djgpp AT delorie DOT com
Subject:	Re: profiling with DJGPP
In-Reply-To:	<2.7.9.GKAP.H3VJYA@pauzner.dnttm.ru>
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Reply-To:	djgpp AT delorie DOT com
Errors-To:	nobody AT delorie DOT com
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On Sat, 12 Oct 2002, Leonid Pauzner wrote:

> > In general, time functions _are_ heavy, since the computations are
> > non-trivial and require iterations in some cases.  You shoulod try to
> > avoid calling time functions in inner loops of your program.
> 
> That is about clock()/CLOCKS_PER_SECOND - is it portable across UNIXes
> and shows correct number of seconds in true multitasking environment?

Yes, `clock' is an ANSI standard function, so every Unix platform 
nowadays should have it.

> Just indexing by the first letter of the environment variable name
> may speeds up getenv by the factor of 10.

If you can come up with a patch to getenv that speeds it up tenfold, I'm 
sure it will be gratefully accepted.

> > Only once: the time functions cache the values of environment
> > variables.  If your program changes the environment a lot (by calling
> > putenv or setenv, for example), then caching could be ineffective,
> > since each time the environment changes, time functions must see if
> > some of their variables changed as well, and take note.  This is so
> > that setting TZ to a different value is correctly handled.
> 
> No!
> The profile shows - each tzset force calling tzsetwall
> (TZ variable is not set in my environment).

Then do set TZ.  Every well-set DJGPP installation should have TZ set to 
something appropriate, especially if you are running Unix programs.

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