In article <42035F4E.6000104@imperial.ac.uk>,
Keean Schupke
SO in effect what you are saying is that system time is likely to be neither TAI nor UTC (as hand setting a clock has a greater than 1 second error usually, a non-networked machine will never tell the right time (and even a stopped clock tells the right time twice a day!).
Can we make that assumption? There might be ways of keeping the clock accurate that don't involve TCP/IP.
I am pretty sure the "clock()" function returns a millisecond count, which added to the hardware time at switch on (as the user cannot adjust time when the machine is switched off - nor can NTP adjust this) gives TAI (possibly with a different start time).
The clock() function drifts and as you say cannot be adjusted, so it cannot be considered TAI. It is however a good choice for timing intervals, as it doesn't hiccup. -- Ashley Yakeley, Seattle WA