MQL5 OrderSend Guide: MqlTradeRequest, Return Codes & Execution Code

//+------------------------------------------------------------------+
//|                                               OrderSendGuide.mq5 |
//|                             Copyright 2026, Pineify Guides Series |
//|                                              https://pineify.app |
//+------------------------------------------------------------------+
#property copyright "Pineify Guides Series"
#property link      "https://pineify.app/mql5/ordersend-guide"
#property version   "1.00"
#property script_show_inputs

//--- Input parameters
input bool EnableDemoOrder=false; // Default only logs; no request sent.
input double InpLotSize          = 0.10;   // Lot Size
input int    InpStopLossPoints   = 200;    // Stop Loss in points
input int    InpTakeProfitPoints = 400;    // Take Profit in points
input ulong  InpSlippagePoints   = 20;     // Slippage in points
input ulong  InpMagicNumber      = 770011; // EA Magic Number

//+------------------------------------------------------------------+
//| Helper: Determine supported filling mode for current symbol      |
//+------------------------------------------------------------------+
bool GetSymbolFillingMode(const string symbol,ENUM_ORDER_TYPE_FILLING &mode)
  {
   long execution=SymbolInfoInteger(symbol,SYMBOL_TRADE_EXEMODE);
   long flags=SymbolInfoInteger(symbol,SYMBOL_FILLING_MODE);
   if(execution==SYMBOL_TRADE_EXECUTION_INSTANT || execution==SYMBOL_TRADE_EXECUTION_REQUEST
      || (flags&SYMBOL_FILLING_FOK)!=0) { mode=ORDER_FILLING_FOK; return true; }
   if((flags&SYMBOL_FILLING_IOC)!=0) { mode=ORDER_FILLING_IOC; return true; }
   if(execution!=SYMBOL_TRADE_EXECUTION_MARKET) { mode=ORDER_FILLING_RETURN; return true; }
   return false;
  }

//+------------------------------------------------------------------+
//| Helper: Send Market Buy Order with Low-Level OrderSend          |
//+------------------------------------------------------------------+
bool SendMarketBuy(double lots, int slPoints, int tpPoints)
  {
   MqlTradeRequest request;
   MqlTradeResult  result;

   // 1. Always zero out request struct to avoid garbage values
   ZeroMemory(request);
   ZeroMemory(result);

   double point  = SymbolInfoDouble(_Symbol, SYMBOL_POINT);
   int digits    = (int)SymbolInfoInteger(_Symbol, SYMBOL_DIGITS);
   double ask    = SymbolInfoDouble(_Symbol, SYMBOL_ASK);

   // 2. Populate trade request
   request.action       = TRADE_ACTION_DEAL;
   request.symbol       = _Symbol;
   request.volume       = lots;
   request.type         = ORDER_TYPE_BUY;
   request.price        = ask;
   request.deviation    = InpSlippagePoints;
   request.magic        = InpMagicNumber;
   if(!GetSymbolFillingMode(_Symbol,request.type_filling)) return false;
   request.comment      = "Pineify OrderSend";

   if(slPoints > 0)
      request.sl = NormalizeDouble(ask - (slPoints * point), digits);
   if(tpPoints > 0)
      request.tp = NormalizeDouble(ask + (tpPoints * point), digits);

   MqlTradeCheckResult check={};
   if(!OrderCheck(request,check))
     { Print("OrderCheck failed: ",check.retcode," ",check.comment); return false; }
   // Passing preflight does not guarantee subsequent execution.
   // 3. Send trade request to server
   if(!OrderSend(request, result))
     {
      PrintFormat("OrderSend critically failed! Retcode: %u, Error: %d",
                  result.retcode, GetLastError());
      return false;
     }

   // 4. Verify execution retcode
   if(result.retcode == TRADE_RETCODE_DONE)
     {
      PrintFormat("OrderSend SUCCESS! Order Ticket: %I64u, Deal: %I64u, Price: %.*f, Vol: %.2f",
                  result.order, result.deal, digits, result.price, result.volume);
      return true;
     }

   if(result.retcode==TRADE_RETCODE_PLACED || result.retcode==TRADE_RETCODE_DONE_PARTIAL)
     {
      Print("Accepted/partial state requires reconciliation; do not blindly resend. Order=",result.order," retcode=",result.retcode);
      return false;
     }
   PrintFormat("OrderSend not completed. Retcode: %u (%s)",
               result.retcode, result.comment);
   return false;
  }

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
   if(!EnableDemoOrder) { Print("Demo sending disabled; inspect the request example first."); return; }
   if(AccountInfoInteger(ACCOUNT_TRADE_MODE)!=ACCOUNT_TRADE_MODE_DEMO)
     { Print("Only a demo account is accepted by this example."); return; }
   if(InpLotSize<=0 || InpStopLossPoints<=0 || InpTakeProfitPoints<=0 || InpMagicNumber==0)
     { Print("Invalid inputs"); return; }
   if(PositionSelect(_Symbol)) { Print("Existing symbol position; demo request skipped."); return; }
   Print("Initiating one demo OrderSend request on ", _Symbol);
   SendMarketBuy(InpLotSize, InpStopLossPoints, InpTakeProfitPoints);
  }