bool bIsFirstTick;// It is used to catch the Bar Opening.
datetime dtCurrentBarOpeningTime;

int init()
{
   bIsFirstTick = false;
   dtCurrentBarOpeningTime = Time[0];
   return(0);
}

int start()
{
   // Is this the first tick for the bar
   bIsFirstTick = (dtCurrentBarOpeningTime != Time[0]);
   if(bIsFirstTick)
   {
      dtCurrentBarOpeningTime = Time[0];
   }

...
...



///
/// Exit at a Bar Closing price (almost).
///
/// MetaTrader does not provide an onBarClose event so we are not able to close a position
/// exactly at Bar Closing. We workaround the problem by closing the position within a time span
/// near to the bar closing time. In the cases when there is no any ticks within this period,
/// we close the position att he next bar opening price.
///
int ClosePositionsAtBarClosing(bool bCloseLong, bool bCloseShort, datetime dtClosingTimeSpan)
{
   int  iOrders = OrdersTotal();
   bool bIsOpen = false;

   for(int iOrder = 0; iOrder < iOrders; iOrder++)
   {
      OrderSelect(iOrder, SELECT_BY_POS, MODE_TRADES);
      
      if((OrderType() == OP_BUY || OrderType() == OP_SELL) && OrderSymbol() == Symbol())
      {  // There is an open position for this symbol.

         datetime dtOpeningTime     = Time[0] - TimeSeconds(Time[0]); // The opening time of current bar
         datetime dtClosingTime     = dtOpeningTime + Period() * 60;  // The closing time of current bars
         datetime dtCurrentTickTime = TimeCurrent() ;                 // The time of current tick
         
         if(dtCurrentTickTime > dtClosingTime - dtClosingTimeSpan ||  bIsFirstTick)
         {  // The current tick is within the closing time span or this is the first tick of the bar.

            // Code

         }
       }
    }
}