Implementing a timer using threads

[BCS]

Reply to Frits,

> BCS wrote:
> 
>> while(NothingToDo())
>> thisThread.MarkTime();
>
> Couldn't you just do something like:
> -----
> time_t nextEvent = currentTime() + interval;
> time_t now;
> while (true) {
> while ((now = currentTime()) < nextEvent)
> sleep(nextEvent - now);        // or msleep, if you prefer
> nextEvent += interval;
> action();
> }
> -----
> (where time_t is some type suitable for measuring time)
> That should sleep until it's time, right?
> 

That would work if the end condition is a clock time. It's not quite the 
same problem but what about if you are waiting for some logical condition?