C++ count time overcoming 72 minutes range of clock_t

Question

Hello, I'm trying to count the execution time of part of my application, but since I need to get milliseconds, and I need to get long execution times too. I'm currently using clock_t = clock() from ctime, but it has a range of only 72 minutes I think, which is not suitable for my needs. Is there any other portable way to count large execution times keeping millisecond precision? Or some way so overcome this limitation of clock_t ?

Answer 1

Unfortunately there are none that I know of that are cross-platform (that's not to say there doesn't exist any, however).

Nevertheless, it is easy enough to work around this problem. Just create a separate thread (ex: boost.thread) which sleeps for a long time, adds the time difference so far to a total, then repeats. When the program is shut down, stop the thread where it can also add to this counter before it quits.

Answer 2

Set up separate counters for milliseconds, seconds, minutes, etc. When milliseconds get to 999, add 1 to seconds, when they get to 59 add 1 to minutes. Or you could just set up 2 timers, one for durations up to 60 minutes (ie 60*60*1000 milliseconds) and one for hours.

Answer 3

The first question you need to ask is do you really need millisecond precision in time spans over a hour.

If you do one simple method (without looking around for libraries that do it already)is just track when the timer rolls over and add that to another variable.