以前こちらで紹介されていた決済時のスプレッド制限を追加するコードですが、EAに組み入れたところ、４エラー、１ワーニングが出てしまいました。解決方法をご教示ください。
https://labo.gogojungle.co.jp/articles/1273

extern int spreadLimit = 10; // Maximum spread in points
int OnInit()
{
return(0);
}

int OnDeinit()
{
return(0);
}
void OnTick()
{
//— get number of open orders
int totalOrders = OrdersTotal();

for(int i=totalOrders-1; i>=0; i–)
{
if(OrderSelect(i, SELECT_BY_POS, MODE_TRADES))
{
if(OrderSymbol() == Symbol() && OrderMagicNumber() == MagicNumber) // check if the order is for the current symbol and EA
{
//— check spread before closing
double spread = MarketInfo(OrderSymbol(), MODE_SPREAD);

        if(spread > spreadLimit)
        {
           Print("Spread is too high, closing trade avoided.");
           continue;
        }
        
        //--- close order if conditions are met
        // OrderClose(...) // Please replace with your closing condition
     }
  }

}

return(0);
}

エラー
OnDeinit function declared with wrong type or/and parameters

‘OnTick’ - function already defined and has body

see previous declaration of function ‘OnTick’

‘MagicNumber’ - undeclared identifier

‘return’ - ‘void’ function returns a value