From: Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: question about getkey() , time() and how to pick a char from the screen
Date: 31 Jul 2001 09:55:21 GMT
Organization: Aachen University of Technology (RWTH)
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Gwen <mb11363 AT chello DOT be> wrote:

> How to use correctly time() ? I tried to make a countdown of 3 sec :

> float quantum=3;
> time_t t=time(NULL);
> while (time(NULL) - t < quantum) {

According to the scriptures, you should never do any arithmetics on
time_t yourself. The language standard doesn't let you know what a
time_t variable really contains. Instead, you should use the
'difftime()' function, which exists exactly for that purpose.

> it works, in fact it works till quantum=1, below (like quantum=0.1)
> it acts as quantum=1, why?  

No particular reason. It just does.

> maybe the second is the unit of the function time() ?

In DJGPP and all POSIX-like systems: yes. But it may be better not to
rely on that too much.

-- 
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.