Check for elapsed time?

I would like to repeat a task every 20 seconds is that how to do it?

int timeToWaitInSeconds = 20;
datetime LastTimeRecorded = LONG_MIN;

int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
   
   if (LastTimeRecorded == LONG_MIN)
   {
      LastTimeRecorded = TimeCurrent();
   }

   if (TimeCurrent() - LastTimeRecorded >= timeToWaitInSeconds )
   {
      LastTimeRecorded = TimeCurrent();

      /* code */
   }
   
//--- return value of prev_calculated for next call
   return(rates_total);
  }