Request sending result: MqlTradeResult structure

In response to a trade request executed by the OrderSend or OrderSendAsync functions, which we'll cover in the next section, the server returns the request processing results. For this purpose, a special predefined structure is used MqlTradeResult.

struct MqlTradeResult
{
   uint     retcode;          // Operation result code
   ulong    deal;             // Transaction ticket, if it is completed
   ulong    order;            // Order ticket, if it is placed
   double   volume;           // Trade volume confirmed by the broker
   double   price;            // Trade price confirmed by the broker
   double   bid;              // Current market bid price
   double   ask;              // Current market offer price
   string   comment;          // Broker's comment on the operation
   uint     request_id;       // Request identifier, set by the terminal when sending
   uint     retcode_external; // Response code of the external trading system
};

The following table describes its fields.

Field	Description
retcode	Trade server return code
deal	Deal ticket if it is performed (during the TRADE_ACTION_DEAL trading operation)
order	Order ticket if it is placed (during the TRADE_ACTION_PENDING trading operation)
volume	Trade volume confirmed by the broker (depends on the order execution modes)
price	The price in the deal confirmed by the broker (depends on the deviation field in the trade request, execution mode, and the trading operation)
bid	Current market bid price
ask	Current market ask price
comment	Broker's comment on the trade (by default, it is filled in with the decryption of the trade server return code)
request_id	Request ID which is set by the terminal when sending it to the trade server
retcode_external	Error code returned by the external trading system

As we will see below when conducting trading operations, a variable of type MqlTradeResult is passed as the second parameter by reference in the OrderSend or OrderSendAsync function. It returns the result.

When sending a trade request to the server, the terminal sets the request_id identifier to a unique value. This is necessary for the analysis of subsequent trading events, which is required if an asynchronous function OrderSendAsync is used. This identifier allows you to associate the sent request with the result of its processing passed to the OnTradeTransaction event handler.

The presence and types of errors in the retcode_external field depend on the broker and the external trading system into which trading operations are forwarded.

Request results are analyzed in different ways, depending on the trading operations and the way they are sent. We will deal with this in subsequent sections on specific actions: market buy and sell, placing and deleting pending orders, and modifying and closing positions.

Request validation: OrderCheck

Sending a trade request: OrderSend and OrderSendAsync