From: Matt Hurd (matt.hurd_at_[hidden])
Date: 2004-07-25 20:43:55
On Sat, 24 Jul 2004 11:24:39 +0100, John Maddock <john_at_[hidden]> wrote:
> Just out of interest, what is the problem that prevents the date-time
> library from implementing a microsecond clock using GetSystemTimeAsFileTime
> on Win32?
>
> Thanks,
>
> John.
The resolution supplied by GetSystemTimeAsFileTime may not be what you
think. I get 10 milliseconds resolution out of my machine from the
following code.
#include <Windows.h>
#include <iostream>
int main () {
FILETIME ft1,ft2;
GetSystemTimeAsFileTime( &ft1 );
GetSystemTimeAsFileTime( &ft2 );
std::size_t diff = ft2.dwLowDateTime - ft1.dwLowDateTime;
while (diff == 0)
{
GetSystemTimeAsFileTime( &ft2 );
diff = ft2.dwLowDateTime - ft1.dwLowDateTime;
}
std::cout << "time taken = " << double(ft2.dwLowDateTime -
ft1.dwLowDateTime) /10000 << "milliseconds\n";
system("pause");
return 0;
}
Regards,
Matt Hurd.