MQL5 ReferenceCustom IndicatorsSetIndexBuffer

SetIndexBuffer

The function binds a specified indicator buffer with one-dimensional dynamic array of the double type.

bool  SetIndexBuffer(
   int                    index,         // buffer index
   double                 buffer[],      // array
   ENUM_INDEXBUFFER_TYPE  data_type      // what will be stored
   );

Parameters

index

[in] Number of the indicator buffer. The numbering starts with 0. The number must be less than the value declared in #property indicator_buffers.

buffer[]

[in] An array declared in the custom indicator program.

data_type

[in] Type of data stored in the indicator array. By default it is INDICATOR_DATA (values of the calculated indicator). It may also take the value of INDICATOR_COLOR_INDEX; in this case this buffer is used for storing color indexes for the previous indicator buffer. You can specify up to 64 colors in the #property indicator_colorN line. The INDICATOR_CALCULATIONS value means that the buffer is used in intermediate calculations of the indicator and is not intended for drawing.

Return Value

If successful, returns true, otherwise - false.

Note

After binding, the dynamic array buffer[] will be indexed as in common arrays, even if the indexing of timeseries is pre-installed for the bound array. If you want to change the order of access to elements of the indicator array, use the ArraySetAsSeries() function after binding the array using the SetIndexBuffer() function. Please note that you can't change the size for dynamic arrays set as indicator buffers by the function SetIndexBuffer(). For indicator buffers, all operations of size changes are performed by the executing sub-system of the terminal.

Example:

//+------------------------------------------------------------------+
//|                                              TestCopyBuffer1.mq5 |
//|                        Copyright 2009, MetaQuotes Software Corp. |
//|                                              https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2009, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"

#property indicator_separate_window
#property indicator_buffers 1
#property indicator_plots   1
//---- plot MA
#property indicator_label1  "MA"
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrRed
#property indicator_style1  STYLE_SOLID
#property indicator_width1  1
//--- input parameters
input bool               AsSeries=true;
input int                period=15;
input ENUM_MA_METHOD     smootMode=MODE_EMA;
input ENUM_APPLIED_PRICE price=PRICE_CLOSE;
input int                shift=0;
//--- indicator buffers
double                   MABuffer[];
int                      ma_handle;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   if(AsSeries) ArraySetAsSeries(MABuffer,true);
   Print("Indicator buffer is timeseries = ",ArrayGetAsSeries(MABuffer));
   SetIndexBuffer(0,MABuffer,INDICATOR_DATA);
   Print("Indicator buffer after SetIndexBuffer() is timeseries = ",
         ArrayGetAsSeries(MABuffer));

//--- change the order of accessing elements of the indicator buffer
   ArraySetAsSeries(MABuffer,AsSeries);

   IndicatorSetString(INDICATOR_SHORTNAME,"MA("+period+")"+AsSeries);
//---
   ma_handle=iMA(Symbol(),0,period,shift,smootMode,price);
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//--- Copy the values of the moving average in the buffer MABuffer
   int copied=CopyBuffer(ma_handle,0,0,rates_total,MABuffer);

   Print("MABuffer[0] = ",MABuffer[0]);// Depending on the value AsSeries
                                      // Will receive a very old value
                                      // Or for the current unfinished bar

//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+