Expert Advisor Programming by Andrew R. Young

Order Placement
• MagicNumber – An optional integer value that will identify the order as being placed by a
specific expert advisor. It is highly recommended that you use this.
• Expiration – An optional expiration time for pending orders. Not all brokers accept trade
expiration times – for these brokers, an error will result if an expiration time is specified.
• Arrow – An optional color for the arrow that will be drawn on the chart, indicating the
opening price and time. If no color is specified, the arrow will not be drawn.
The OrderSend() function returns the ticket number of the order that was just placed. If no order
was placed, due to an error condition, the return value will be -1.
We can save the order ticket to a global or static variable for later use. If the order was not placed
due to an error condition, we can analyze the error and take appropriate action based on the
returned error code.
Placing A Market Order
Here's an example of a buy market order. We'll assume that the variables LotSize, Slippage,
BuyStopLoss, BuyTakeProfit and MagicNumber have already been calculated or assigned and are
valid.
OrderSend(Symbol(),OP_BUY,LotSize,Ask,Slippage,BuyStopLoss,BuyTakeProfit,
"Buy Order",MagicNumber,0,Green);
The Symbol() function returns the current chart symbol. We will be placing orders on the current
chart pair 99% of the time. OP_BUY indicates that this is a buy market order. Ask is a predefined
variable in MQL that stores the most recent Ask quote. (Remember that buy orders open at the Ask
price!)
The Slippage is set using an external variable. The slippage parameter is an integer, indicating the
number of points to allow for price slippage. If your broker uses 4 digit quotes (2 for Yen pairs), 1
point would be equal to 1 pip. If your broker offers 3 and 5 digit quotes however, then 1 point would
be 0.1 pips. In this case, you'd need to add an additional zero to the end of your Slippage setting.
We've added the generic comment "Buy Order" to this order. Since there is no expiration for market
orders, the Expiration parameter is 0. Finally, we specify the color constant Green to draw a green
arrow on the chart.
Here is an example of a sell market order, using the same parameters as above:
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