OnTimer() trong MQL5: Scheduled Events

OnTimer(): Time-Based Event Handler

OnTimer() được gọi theo chu kỳ cố định (ví dụ mỗi 60 giây). Hữu ích cho tasks không cần chạy mỗi tick.

Setup Timer

int OnInit() {
    // Set timer: every 60 seconds
    if(EventSetTimer(60)) {
        Print("Timer set: 60 seconds");
        return INIT_SUCCEEDED;
    } else {
        Print("Failed to set timer");
        return INIT_FAILED;
    }
}

void OnTimer() {
    Print("Timer event at ", TimeToString(TimeCurrent()));
    // Code runs every 60 seconds
}

void OnDeinit(const int reason) {
    EventKillTimer();
    Print("Timer stopped");
}

Ứng Dụng: Account Monitoring

void OnTimer() {
    // Check account status every minute
    double balance = AccountInfoDouble(ACCOUNT_BALANCE);
    double equity = AccountInfoDouble(ACCOUNT_EQUITY);
    double margin = AccountInfoDouble(ACCOUNT_MARGIN);
    double freeMargin = AccountInfoDouble(ACCOUNT_MARGIN_FREE);
    
    Print("=== Account Status ===");
    Print("Balance: $", balance);
    Print("Equity: $", equity);
    Print("Margin: $", margin);
    Print("Free Margin: $", freeMargin);
    
    // Check risk
    double drawdown = (balance - equity) / balance * 100;
    if(drawdown > 10) {
        Print("⚠️ WARNING: Drawdown > 10%!");
        SendEmail("Risk Alert", "Drawdown exceeded 10%");
    }
}

Best Practices

• ✅ Use OnTimer() cho periodic checks
• ✅ Typical intervals: 60s, 300s, 3600s
• ✅ Ideal cho: monitoring, logging, email alerts
• ⛔ Không dùng cho real-time trading logic