Re: [Dev-C++] Calculating Time in milliseconds

[Rob L. <rob...@nt...>]

sorry but i would like relative time in ms resolution....
i tried using the getTickCount() but this does not seem to be very accurate
if i need an ms value <32 ms
any other suggestions?
also is nanosecond resolution possible?
regards
Rob
----- Original Message -----
From: "Per Westermark" <pw...@ia...>
To: "Rob Lawless" <rob...@nt...>
Cc: "DEV-CPP" <dev...@li...>
Sent: Monday, November 08, 2004 10:55 PM
Subject: Re: [Dev-C++] Calculating Time in milliseconds


> Do you want absolute time or relative time in ms resolution?
>
> For Win32, you can use GetTickCount() that gives number of ms since the
> machine booted. It overflows every 49.7 days.
>
> However, it doesn't tick every ms. For a workstation I think it change
> value every 32 ms.
>
> I haven't bothered to test, but I think the tick interval depends on the
> length of time strata used by the windows installation for task switching,
> i.e. it will vary between workstation and server installation.
>
> For better time intervals you can use the performance counters in windows
> - they count time in clock cycles of the processor.
>
> On a unix machine you can use gettimeofday() to get absolute time down
> to us resolution, but for this function too, the time is of course not
> stepped every microsecond. Note that this function - as compared to the
> Win32 GetTickCount() function - takes some time to call, so a program
> making large amount of calls will get slowed down.
>
> /Per W
>
> On Mon, 8 Nov 2004, Rob Lawless wrote:
>
> > Hey folks just reading the <ctime> documentation which can only specify
a mimimun time in seconds...does anyone know how to calulate a time interval
in milliseconds?
> > regards
> > Rob
>