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

From: Pavel Vozenilek (pavel_vozenilek_at_[hidden])
Date: 2003-03-24 15:05:20

"Alisdair Meredith" <alisdair.meredith_at_[hidden]> wrote in message
news:3E7F0259.D13E8F4B_at_uk.renaultf1.com...
> Russell Hind wrote:
>
> WinAPI Note: we can get a higher resolution using the
> QueryPerformanceCounter API (and QueryPerformanceFrequency if resolution
> info is required)
>
It is (was) not completely reliable: see Q274323 bug in MS Knowledgebase:

"Symptoms: The result that is returned by the QueryPerformanceCounter
function may unexpectedly leap forward from time to time. This leap may
represent several seconds."

The MSDN article specifies what HW can cause the problem and how to work it
around.

/Pavel

PS: my experience with this API is positive, I got resolution cca ~1
microsecond and the call overhead was tiny.