I need a timer that has sub-second precision and can time for longer
than 2 hours.

I have used the clock_t data type and the clock() function to
determine the elapsed time of a calculation. A problem arose when the
elapsed time was more than 1 hour and 20 minutes, the clock_t data
would wrap around and the time difference would become negative.

I started looking at using the time_t data type. It looks like it can
do a large enough time difference, but it lacks the sub-second
precision I desire.

Does anyone know if what I want is possible? Am I going to have to
use two different timers; one for long times and one for short times?

Thanks,
Jeremy

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jeremit0 wrote:

> I need a timer that has sub-second precision and can time for longer
> than 2 hours.

Hows about gettimeofday ?

http://www.opengroup.org/onlinepubs/...timeofday.html

If your system provides it

O.


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jeremit0 ha scritto:
> I need a timer that has sub-second precision and can time for longer
> than 2 hours.
>
> I have used the clock_t data type and the clock() function to
> determine the elapsed time of a calculation. A problem arose when the
> elapsed time was more than 1 hour and 20 minutes, the clock_t data
> would wrap around and the time difference would become negative.
>
> I started looking at using the time_t data type. It looks like it can
> do a large enough time difference, but it lacks the sub-second
> precision I desire.
>
> Does anyone know if what I want is possible? Am I going to have to
> use two different timers; one for long times and one for short times?
>

Have you tried Boost.DateTime?

http://www.boost.org/doc/libs/1_35_0...date_time.html

the boost::ptime class uses 64-bits with microsecond resolution, which
should be quite enough for your needs.

Ganesh

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jeremit0 schrieb:
> I need a timer that has sub-second precision and can time for longer
> than 2 hours.

> Does anyone know if what I want is possible? Am I going to have to
> use two different timers; one for long times and one for short times?

Not in C++, but POSIX offers gettimeofday() which might do what you want.

Greetings,
Thomas

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On Aug 1, 11:44 am, Oncaphillis <oncaphil...@snafu.de> wrote:
> jeremit0 wrote:
> > I need a timer that has sub-second precision and can time for longer
> > than 2 hours.
>
> Hows about gettimeofday ?
>
> http://www.opengroup.org/onlinepubs/...s/gettimeofday....
>
> If your system provides it

This sounds like another good suggestion. The code does have to be
platform independent–OS X and Linux mostly–so I'll take that into
consideration. I'll take a look to see if it works for me.

Thanks,
Jeremy


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On Fri, 1 Aug 2008 18:53:15 CST, jeremit0 <jeremit0@gmail.com> wrote:

[gettimeofday(2)]

> This sounds like another good suggestion. The code does have to be
> platform independent -- OS X and Linux mostly -- so I'll take that into
> consideration.

This is slightly off-topic, but I cannot help mentioning it: OS X and
Linux are, for these purposes, the same platform. They're modern Unix
systems. You probably have no reason to worry unless you target Windows,
IBM mainframes, or exotic embedded environments.

You might want to read up a bit on Unix standards like Posix and the
Single UNIX Specification, and compare to the documentation that comes
with your systems.

/Jorgen

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