Re: [boost] Re: [date_time] enabling microsec_clock under C++Builder

From: Beman Dawes (bdawes_at_[hidden])
Date: 2003-03-24 09:14:31

At 08:04 AM 3/24/2003, Alisdair Meredith wrote:
 >Russell Hind wrote:
 >
 >> I agree with that.  Would it be better to make it a millisec_clock, or
 >> just use the microsec_clock but the resolution is only milliseconds?
 >
 >WinAPI Note: we can get a higher resolution using the
 >QueryPerformanceCounter API (and QueryPerformanceFrequency if resolution
 >info is required)

Be careful. At least with some older versions of Windows, the execution 
time for some of the Windows time related API's was so large that the 
useful resolution was nowhere near the apparent claimed resolution.

If a function that is supposed to measure time in microseconds takes 
several milliseconds to execute, it seems to me the useful resolution is 
really milliseconds rather than microseconds.

It might be interesting to write a little test program and run it on modern 
versions of Windows to see it this problem still exists.

--Beman