OrderModify HOW

Example from file: examples\demos\lowlevel\02_trading_operations.go

The OrderModify() method is used to modify parameters of an already opened position or order, such as adding Stop Loss (SL) and Take Profit (TP) levels. This call does not open a new trade — it updates an existing one by its ticket.

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🧩 Code example

fmt.Println("\n4.2. OrderModify() - Add Stop Loss and Take Profit")

// Calculate SL/TP levels (10 pips SL, 20 pips TP)
stopLoss := sendData.Price - (10 * pipSize)
takeProfit := sendData.Price + (20 * pipSize)

modifyReq := &pb.OrderModifyRequest{
    Ticket:     orderTicket,
    StopLoss:   &stopLoss,
    TakeProfit: &takeProfit,
}

modifyData, err := account.OrderModify(ctx, modifyReq)
if !helpers.PrintShortError(err, "OrderModify failed") {
    fmt.Printf("  Order modify result:\n")
    fmt.Printf("    Return Code:                 %d\n", modifyData.ReturnedCode)
    fmt.Printf("    Order Ticket:                %d\n", modifyData.Order)
    fmt.Printf("    Stop Loss:                   %.5f\n", stopLoss)
    fmt.Printf("    Take Profit:                 %.5f\n", takeProfit)
    fmt.Printf("    Comment:                     %s\n", modifyData.Comment)

    // Check if modification was successful using helper from errors.go
    if mt5.IsRetCodeSuccess(modifyData.ReturnedCode) {
        fmt.Printf("    ✓ Position MODIFIED successfully!\n")
    } else {
        fmt.Printf("    ❌ Modification failed: %s (code: %d)\n",
            mt5.GetRetCodeMessage(modifyData.ReturnedCode),
            modifyData.ReturnedCode)
    }
}

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🟢 Detailed Code Explanation

1️. Calculate SL and TP Levels

stopLoss := sendData.Price - (10 * pipSize)
takeProfit := sendData.Price + (20 * pipSize)

After the order is opened (OrderSend() returned sendData.Price), stop levels are calculated:

• StopLoss is set 10 pips below the opening price;
• TakeProfit — 20 pips above.

pipSize — size of one pip (for EURUSD = 0.0001).

💡 This way we programmatically set protection levels and profit targets.

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2️. Form the Modification Request

modifyReq := &pb.OrderModifyRequest{
    Ticket:     orderTicket,
    StopLoss:   &stopLoss,
    TakeProfit: &takeProfit,
}

Create the OrderModifyRequest structure.

Field	Description
Ticket	Order number to modify (obtained from OrderSend()).
StopLoss	Stop loss price. Uses pointer (&), as the field is optional.
TakeProfit	Take profit price. Also a pointer.

You can pass only one of these fields if you need to change only SL or TP.

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3️. Send Request to Broker

modifyData, err := account.OrderModify(ctx, modifyReq)

The gateway method calls OrderModify() on the MetaTrader side. The server validates level correctness (e.g., SL/TP must not be closer than the minimum StopsLevel distance).

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4️. Parse the Response

fmt.Printf("    Return Code: %d\n", modifyData.ReturnedCode)
fmt.Printf("    Order Ticket: %d\n", modifyData.Order)
fmt.Printf("    Stop Loss: %.5f\n", stopLoss)
fmt.Printf("    Take Profit: %.5f\n", takeProfit)
fmt.Printf("    Comment: %s\n", modifyData.Comment)

Key fields:

• ReturnedCode — operation status (10009 = successfully executed);
• Order — ticket of the modified order;
• Comment — server response (e.g., "Request executed successfully").

---

5️. Verify Operation Success

// Check if modification was successful using helper from errors.go
if mt5.IsRetCodeSuccess(modifyData.ReturnedCode) {
    fmt.Printf("    ✓ Position MODIFIED successfully!\n")
} else {
    fmt.Printf("    ❌ Modification failed: %s (code: %d)\n",
        mt5.GetRetCodeMessage(modifyData.ReturnedCode),
        modifyData.ReturnedCode)
}

Why use mt5.IsRetCodeSuccess() instead of checking == 10009 manually?

1. Self-Documenting: The function name clearly explains what is being validated
2. Centralized Logic: Single source of truth for success validation in package/Helpers/errors.go
3. Better Error Messages: mt5.GetRetCodeMessage() automatically provides human-readable descriptions for common errors like:
4. TRADE_RETCODE_INVALID_STOPS - SL/TP levels too close to market price
5. TRADE_RETCODE_INVALID_ORDER - Order already closed or doesn't exist
6. TRADE_RETCODE_REQUOTE - Price changed, need to retry
7. Consistency: All code examples use the same error checking pattern

Code 10009 (TRADE_RETCODE_DONE) means the changes were applied successfully.

If the code is different — the broker rejected the request. The helper functions provide detailed error descriptions to understand why. Common reasons include: - SL/TP levels too close (violating SYMBOL_TRADE_STOPS_LEVEL) - Order already closed - Invalid ticket number

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📦 What the Server Returns

message OrderModifyData {
  uint32 ReturnedCode = 1;  // Result code (TRADE_RETCODE_*)
  uint64 Order = 2;         // Order number
  string Comment = 3;       // Broker comment
}

---

💡 Example Output

Order modify result:
    Return Code:                 10009
    Order Ticket:                128013245
    Stop Loss:                   1.08442
    Take Profit:                 1.08742
    Comment:                     Request executed successfully
    ✓ Position MODIFIED successfully!

---

🧠 What It's Used For

The OrderModify() method is used for:

• setting Stop Loss and Take Profit after opening a trade;
• changing existing SL/TP levels;
• managing active positions from code;
• adapting orders to market conditions without closing the position.

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💬 In Simple Terms

OrderModify() is editing an open position. It allows you to add or change stop loss and take profit for an existing order. If everything is correct (code 10009), the broker applies the changes, and the trade is updated on the server.