[amibroker] Simple slippage implemented in CBT generates COM error

[ozzyapeman]

Hello, hoping someone can help on this. I am using ApplyStop, which does
not have a slippage factor. I'm trying to avoid using a BarCount loop to
implement slippage on exits and instead am trying to modify the signal
list of the CBT to implement slippage,  before the backtester engine
processes the trades.

But I am running into two problems, namely:


1.   Get error COM method/function 'GetFirstSignal' call failed, on the
for loop line, even though that line and prior ones were copied and
pasted direct from the reference guide.


2.  More of a question at this point: What if my calculation of ExitTrue
price is below the Low, or above the High of the bar? Will the
backtester engine simply ignore that signal? Or is there some way I can
filter out that possibility directly in the code below?



In this example, Slippage = 0.0002 elsewhere in my code, backtesting on
Forex:


SetCustomBacktestProc( "" );

if ( Status( "action" ) == actionPortfolio )
{
   bo = GetBacktesterObject();

     for( sig = bo.GetFirstSignal(); sig; sig = bo.GetNextSignal() )
      {
         if( sig.IsExit() )
          {
            if ( sig.IsLong() ) // Exit Long
             {
              ExitTrue  = sig.Price - Slippage;
              sig.Price = ExitTrue;
              }

             else               // Exit Short
              {
              ExitTrue  = sig.Price + Slippage;
              sig.Price = ExitTrue;
              }

          }
       }
}