"Russell Hind" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Johan Nilsson wrote: > > > > Perhaps, but one should consider that GetSystemTime promises 1ms resolution > > and delivers 10-15ms (and, IIRC, that GetSystemTimeAsFileTime promises > > 250ns resolution). > > > > The Platform SDK states that the tickcount (GetTickCount) is updated > every 10ms on NT3.51 and hight so I guess that GetSystemTime is updated > at this interval also.
That's correct for uniprocessor machines. It is normally 15ms on SMP machines (at least on NT 4.0 upwards). As I said earlier, my only experience is with x86 machines (and NT, not Win9x et al). > > FileTimes are measured in 100 nanosecond intervals since 1 January, > 1601, but are you sure that GetSystemTimeAsFileTime will return a value > that is updated at 250ns intervals? I can't find anything in the SDK to > say what the update interval is for the SystemTime, I'm just guessing > that it is updated when the tick count is. Sorry - just a case of bad memory - 100ns is of course correct. I am definitely sure that GetSystemTimeAsFileTime will _not_ return a value that is updated more frequently than the system's tick interval. I just wanted to point out the similarity between: - GSTAFT having a 100ns resolution but not being updated more often than 10-15ms - microsec_clock having a microsec resolution but not being updated more often than 10-15ms // Johan _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
