Im usless with c-script, so I hope you after a lite-c result.

USAGE: (TESTED)
ALWAYS needs to called with VAR variables in all 3 parameters.
First call starts the timer, second call stops it and injects the elapsed time into the 3 var parameters.
IF there are values in the parameters VARs as first-call, these are used as a starting-point by the timer.
So you can do
Code:
   var HH=0, MM=0, SS=0;
   StopWatch(HH, MM, SS);  //timer started at ZEROs
   ...
   StopWatch(HH, MM, SS);  //Stop timer and HH, MM, SS = elapsed time
   StopWatch(HH, MM, SS);  //Restart timer at HH, MM, SS elapsed time (NO time lost)
   ...
   StopWatch(HH, MM, SS);  //Stop timer and HH, MM, SS = elapsed time
STOPWATCH Function itself
Code:
void StopWatch(var* Hours, var* Minutes, var* Seconds)
{
    static var hours, minutes, seconds, running=0;
    if(running==0)
    {    //START StopWatch
        running = 1;
        hours=*Hours;    minutes=*Minutes;    seconds=*Seconds;
        while(running)
        {
            wait(1);
            seconds += (timer()/1000000);
            if(seconds>=60)
            {
                minutes += integer(seconds/60);
                seconds  = cycle(seconds,0,60);
                if(minutes>=60)
                {
                    hours  += integer(minutes/60);
                    minutes = cycle(minutes,0,60);
                }
            }
        }
        return;
    }
    //STOP StopWatch
    *Hours = hours;    *Minutes = minutes;    *Seconds = seconds;
    running=0;
    return;
}
If this is needed in C-script, I'll need you to let me know, and I'll need more time...

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