Re: elapsed time 0 with std::cin

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 24 Nov 2007 10:16:27 -0800 (PST)
Message-ID:
<528970dc-e70c-4f64-88ef-422a5ff0da3a@x69g2000hsx.googlegroups.com>
On Nov 24, 4:29 pm, "Christopher Pisz" <some...@somewhere.net> wrote:

"pekka" <pe...@nospam.invalid> wrote in message

news:pan.2007.11.24.11.53.24.412744@nospam.invalid...

On Fri, 23 Nov 2007 21:16:06 -0600, Christopher Pisz wrote:

If you are looking to do a timer, you are better off using
a OS specific timer. The ctime family is really only good
for precisions of 1 second. Things like input can happen
more often than 1 second. I am fairly certain that *nix
offers some form of high precision timer and I know that MS
does. You'll have to google around a bit.


Most C++ timers I've seen so far are based on the same idea
as my code (e.g. boost::timer), but I'll keep on searching.


If on windows QueryPerformanceTimer offer very high precision
I don't know what the Linux equivalent is, but I am sure it
exists


Posix required clock() to have a granularity of one microsecond.
=46rom a QoI point of view, I would expect clock() to give the
maximum precision available, up to that granularity. (IIRC,
Windows requires clock() to have a granularity of 1 millisecond.
On the other hand, at least with VC++, the function doesn't
work, so it doesn't matter.)

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