title: MQL4 iCustom prev_calculated is always 0 when calling different symbols in one symbol with EA
body: <p>I am creating an EA which scans all the symbols in the market watch. In that, every symbol runs a set of custom indicator which I developed.</p>
  <p>From this, I am getting &quot;indicator is too slow, 5640 ms. rewrite the indicator, please&quot; this issue in most of the indicators.</p>
  <p>I am using &quot; int Nbars = rates_total - prev_calculated - 1;&quot; this in all indicators. So when a symbol loads at the first time, it returns total bars and after that, it will load only new bars( the value will be 0 or -1).</p>
  <p>But I am facing the issue, every time it loads a symbol, OnInit() is called and prev_calculated is always 0. It is not returning the previous call.</p>
  <p>I read the MQL document which is</p>
  <p>If since the last call of OnCalculate() price data has changed (a deeper history downloaded or history blanks filled), the value of the input parameter prev_calculated will be set to zero by the terminal.</p>
  <p>But I don't know why it is returning the calculated rates_total.</p>
  <p>Kindly give your valuable solution</p>
  <p>Thanks in advance !</p>