Reading Indicator Values

Overview

In MQL5, indicator outputs are stored in buffers. You access these buffers programmatically using a handle (e.g., from iMA(), iRSI()) and the CopyBuffer() function. This lets your scripts and Expert Advisors consume analytical data directly for decisions.

What You Will Be Able to Do

• Create an indicator handle (e.g., Moving Average) and manage its lifecycle.
• Read recent values from indicator buffers using CopyBuffer().
• Interpret buffer indexing (current bar vs. previous bars).
• Print values to the Experts log to verify correctness.

Code Example

//+------------------------------------------------------------------+
//|                                           ReadIndicatorValues.mq5 |
//+------------------------------------------------------------------+
#property version "1.00"
#property strict

input int                 Period = 14;
input ENUM_MA_METHOD      Method = MODE_SMA;
input ENUM_APPLIED_PRICE  Price  = PRICE_CLOSE;
input int                 Count  = 5;   // how many recent values to read

void OnStart()
  {
   // 1) Create a handle for the built-in Moving Average
   int ma = iMA(_Symbol, _Period, Period, 0, Method, Price);
   if(ma == INVALID_HANDLE)
     {
      Print("Error: failed to create MA handle");
      return;
     }

   // 2) Prepare a buffer and read values
   double buf[];
   ArraySetAsSeries(buf, true);  // index 0 = most recent bar
   int copied = CopyBuffer(ma, 0, 0, Count, buf);
   if(copied <= 0)
     {
      Print("Error: CopyBuffer failed. copied=", copied);
      IndicatorRelease(ma);
      return;
     }

   // 3) Print latest values
   int digits = (int)SymbolInfoInteger(_Symbol, SYMBOL_DIGITS);
   for(int i = 0; i < copied; i++)
      Print(StringFormat("MA[%d] = %s", i, DoubleToString(buf[i], digits)));
      // i=0 is the current (forming) bar, i=1 previous closed bar, etc.

   // 4) Clean up
   IndicatorRelease(ma);
  }

Execution Steps

1. Open MetaEditor → File → New → Script and name it ReadIndicatorValues.
2. Paste the code and press F7 to compile.
3. Attach the script to any chart in MetaTrader 5.
4. Open the Experts tab to see printed MA values for bars [0..Count-1].
5. (Optional) Change Period/Method or switch to another handle, e.g., iRSI(). For multi-buffer indicators such as MACD, select buffer indexes (e.g., main=0, signal=1, hist=2).

Key Point

Indicator outputs live in buffers. Create a handle, call CopyBuffer() for the desired buffer index and bar range, then release the handle with IndicatorRelease(). Use ArraySetAsSeries(true) when you want buf[0] to represent the most recent bar.

Next Section

→ Next: What Is an Expert Advisor