Mql4 Tutorial: How to Get Detailed Symbol Properties with SymbolInfoInteger(), SymbolInfoDouble(), and SymbolInfoString()

To programmatically retrieve contract details in MQL4, you can use two primary sets of functions: the newer SymbolInfo... functions (recommended for compatibility and detail) or the legacy MarketInfo() function.

Below is a script that demonstrates how to retrieve and print the specific details you requested (Swap, Tick Size, Lot Size) along with other essential contract specifications.

MQL4 Script: Get Contract Details

This script allows you to input a symbol name (or use the current chart's symbol) and prints the details to the "Experts" tab in the Terminal.

//+------------------------------------------------------------------+
//|                                          GetContractDetails.mq4  |
//|                        Copyright 2023, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2023, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property strict
#property script_show_inputs

//--- Input Parameters
input string InpSymbol = ""; // Symbol (leave empty for current chart)

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
{
   // 1. Determine the symbol to check
   string symbol = InpSymbol;
   if(symbol == "") symbol = _Symbol; // Use current chart symbol if input is empty

   // 2. Ensure the symbol is selected in Market Watch to get fresh data
   if(!SymbolSelect(symbol, true))
   {
      Print("Error: Symbol ", symbol, " not found or could not be selected.");
      return;
   }

   // 3. Retrieve Integer Properties
   int digits        = (int)SymbolInfoInteger(symbol, SYMBOL_DIGITS);
   int spread        = (int)SymbolInfoInteger(symbol, SYMBOL_SPREAD);
   int stopLevel     = (int)SymbolInfoInteger(symbol, SYMBOL_TRADE_STOPS_LEVEL);
   int swapMode      = (int)SymbolInfoInteger(symbol, SYMBOL_SWAP_MODE);

   // 4. Retrieve Double Properties (The specific details you asked for)
   double tickSize   = SymbolInfoDouble(symbol, SYMBOL_TRADE_TICK_SIZE);
   double tickValue  = SymbolInfoDouble(symbol, SYMBOL_TRADE_TICK_VALUE);
   
   double minLot     = SymbolInfoDouble(symbol, SYMBOL_VOLUME_MIN);
   double maxLot     = SymbolInfoDouble(symbol, SYMBOL_VOLUME_MAX);
   double lotStep    = SymbolInfoDouble(symbol, SYMBOL_VOLUME_STEP);
   
   double swapLong   = SymbolInfoDouble(symbol, SYMBOL_SWAP_LONG);
   double swapShort  = SymbolInfoDouble(symbol, SYMBOL_SWAP_SHORT);
   
   double point      = SymbolInfoDouble(symbol, SYMBOL_POINT);
   double contract   = SymbolInfoDouble(symbol, SYMBOL_TRADE_CONTRACT_SIZE);

   // 5. Helper to describe Swap Mode
   string swapModeDesc;
   switch(swapMode)
   {
      case 0: swapModeDesc = "Points"; break;
      case 1: swapModeDesc = "Base Currency"; break;
      case 2: swapModeDesc = "Interest"; break;
      case 3: swapModeDesc = "Margin Currency"; break;
      default: swapModeDesc = "Unknown";
   }

   // 6. Print the Report
   Print("========== Contract Details: ", symbol, " ==========");
   Print("--- Pricing ---");
   PrintFormat("Digits: %d", digits);
   PrintFormat("Point: %.5f", point);
   PrintFormat("Tick Size: %.5f", tickSize);
   PrintFormat("Tick Value: %.2f (in deposit currency)", tickValue);
   PrintFormat("Spread: %d points", spread);
   PrintFormat("Stop Level: %d points", stopLevel);
   
   Print("--- Volume (Lots) ---");
   PrintFormat("Min Lot: %.2f", minLot);
   PrintFormat("Max Lot: %.2f", maxLot);
   PrintFormat("Lot Step: %.2f", lotStep);
   PrintFormat("Contract Size: %.2f", contract);
   
   Print("--- Swaps ---");
   PrintFormat("Swap Mode: %s", swapModeDesc);
   PrintFormat("Swap Long: %.2f", swapLong);
   PrintFormat("Swap Short: %.2f", swapShort);
   Print("================================================");
}

Key Functions Used

1. SymbolInfoDouble(symbol, PROPERTY_ID):

   • SYMBOL_TRADE_TICK_SIZE: The minimum price change.
   • SYMBOL_VOLUME_MIN: The minimum lot size allowed.
   • SYMBOL_SWAP_LONG / SYMBOL_SWAP_SHORT: The swap rates.
   • SYMBOL_TRADE_TICK_VALUE: The value of a single tick in the account currency (crucial for risk management).

2. SymbolInfoInteger(symbol, PROPERTY_ID):

   • SYMBOL_SWAP_MODE: Tells you how the swap is calculated (e.g., in points, currency, or percentage).
   • SYMBOL_DIGITS: The number of decimal places.

3. SymbolSelect(symbol, true):

   • Ensures the symbol exists and is available in the "Market Watch" window. If a symbol is not selected, SymbolInfo functions might return outdated or zero values.

Alternative: Using MarketInfo (Legacy)

If you are maintaining older code, you might see MarketInfo. It performs the same task but uses different constants.

double tickSize = MarketInfo(Symbol(), MODE_TICKSIZE);
double minLot   = MarketInfo(Symbol(), MODE_MINLOT);
double swapLong = MarketInfo(Symbol(), MODE_SWAPLONG);

Q&A

Q: Why is SymbolInfoDouble preferred over MarketInfo?
A: SymbolInfoDouble is the modern standard that aligns with MQL5 syntax, making it easier to port code between MT4 and MT5. It also supports a wider range of properties than the older MarketInfo.

Q: Why do I get 0 for Tick Value?
A: This usually happens if the symbol is not selected in the Market Watch window. The script above uses SymbolSelect to prevent this.

Q: How do I calculate the cost of a swap in money?
A: It depends on the SYMBOL_SWAP_MODE.

• If mode is Points (0): SwapCost = SwapRate * PointValue * Lots.
• If mode is Money (1 or 3): SwapCost = SwapRate * Lots.
• If mode is Interest (2): The calculation involves the current price and annual interest logic.