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ArrayFree

It frees up a buffer of any dynamic array and sets the size of the zero dimension to 0.

void  ArrayFree(
   void&  array[]      // array
   );

Parameters

array[]

[in]  Dynamic array.

Return Value

No return value.

Note

The need for using ArrayFree() function may not appear too often considering that all used memory is freed at once and main work with the arrays comprises the access to the indicator buffers. The sizes of the buffers are automatically managed by the terminal's executive subsystem.

In case it is necessary to manually manage the memory in complex dynamic environment of the application, ArrayFree() function allows users to free the memory occupied by the already unnecessary dynamic array explicitly and immediately.

Example:

#include <Controls\Dialog.mqh>
#include <Controls\Button.mqh>
#include <Controls\Label.mqh>
#include <Controls\ComboBox.mqh>
//--- predefined constants
#define X_START 0
#define Y_START 0
#define X_SIZE 280
#define Y_SIZE 300
//+------------------------------------------------------------------+
//| Dialog class for working with memory                             |
//+------------------------------------------------------------------+
class CMemoryControl : public CAppDialog
  {
private:
   //--- array size
   int               m_arr_size;
   //--- arrays
   char              m_arr_char[];
   int               m_arr_int[];
   float             m_arr_float[];
   double            m_arr_double[];
   long              m_arr_long[];
   //--- labels
   CLabel            m_lbl_memory_physical;
   CLabel            m_lbl_memory_total;
   CLabel            m_lbl_memory_available;
   CLabel            m_lbl_memory_used;
   CLabel            m_lbl_array_size;
   CLabel            m_lbl_array_type;
   CLabel            m_lbl_error;
   CLabel            m_lbl_change_type;
   CLabel            m_lbl_add_size;
   //--- buttons
   CButton           m_button_add;
   CButton           m_button_free;
   //--- combo boxes
   CComboBox         m_combo_box_step;
   CComboBox         m_combo_box_type;
   //--- current value of the array type from the combo box
   int               m_combo_box_type_value;
 
public:
                     CMemoryControl(void);
                    ~CMemoryControl(void);
   //--- class object creation method
   virtual bool      Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2);
   //--- handler of chart events
   virtual bool      OnEvent(const int id,const long &lparam,const double &dparam,const string &sparam);
 
protected:
   //--- create labels
   bool              CreateLabel(CLabel &lbl,const string name,const int x,const int y,const string str,const int font_size,const int clr);
   //--- create control elements
   bool              CreateButton(CButton &button,const string name,const int x,const int y,const string str,const int font_size,const int clr);
   bool              CreateComboBoxStep(void);
   bool              CreateComboBoxType(void);
   //--- event handlers
   void              OnClickButtonAdd(void);
   void              OnClickButtonFree(void);
   void              OnChangeComboBoxType(void);
   //--- methods for working with the current array
   void              CurrentArrayFree(void);
   bool              CurrentArrayAdd(void);
  };
//+------------------------------------------------------------------+
//| Free memory of the current array                                 |
//+------------------------------------------------------------------+
void CMemoryControl::CurrentArrayFree(void)
  {
//--- reset array size
   m_arr_size=0;
//--- free the array
   if(m_combo_box_type_value==0)
      ArrayFree(m_arr_char);
   if(m_combo_box_type_value==1)
      ArrayFree(m_arr_int);
   if(m_combo_box_type_value==2)
      ArrayFree(m_arr_float);
   if(m_combo_box_type_value==3)
      ArrayFree(m_arr_double);
   if(m_combo_box_type_value==4)
      ArrayFree(m_arr_long);
  }  
//+------------------------------------------------------------------+
//| Attempt to add memory for the current array                      |
//+------------------------------------------------------------------+
bool CMemoryControl::CurrentArrayAdd(void)
  {
//--- exit if the size of the used memory exceeds the size of the physical memory
   if(TerminalInfoInteger(TERMINAL_MEMORY_PHYSICAL)/TerminalInfoInteger(TERMINAL_MEMORY_USED)<2)
      return(false);
//--- attempt to allocate memory according to the current type
   if(m_combo_box_type_value==0 && ArrayResize(m_arr_char,m_arr_size)==-1)
      return(false);
   if(m_combo_box_type_value==1 && ArrayResize(m_arr_int,m_arr_size)==-1)
      return(false);
   if(m_combo_box_type_value==2 && ArrayResize(m_arr_float,m_arr_size)==-1)
      return(false);
   if(m_combo_box_type_value==3 && ArrayResize(m_arr_double,m_arr_size)==-1)
      return(false);
   if(m_combo_box_type_value==4 && ArrayResize(m_arr_long,m_arr_size)==-1)
      return(false);
//--- memory allocated
   return(true);
  }  
//+------------------------------------------------------------------+
//| Handling events                                                  |
//+------------------------------------------------------------------+
EVENT_MAP_BEGIN(CMemoryControl)
ON_EVENT(ON_CLICK,m_button_add,OnClickButtonAdd)
ON_EVENT(ON_CLICK,m_button_free,OnClickButtonFree)
ON_EVENT(ON_CHANGE,m_combo_box_type,OnChangeComboBoxType)
EVENT_MAP_END(CAppDialog)
//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CMemoryControl::CMemoryControl(void)
  {
  }
//+------------------------------------------------------------------+
//| Destructor                                                       |
//+------------------------------------------------------------------+
CMemoryControl::~CMemoryControl(void)
  {
  }
//+------------------------------------------------------------------+
//| Class object creation method                                     |
//+------------------------------------------------------------------+
bool CMemoryControl::Create(const long chart,const string name,const int subwin,
                            const int x1,const int y1,const int x2,const int y2)
  {
//--- create base class object
   if(!CAppDialog::Create(chart,name,subwin,x1,y1,x2,y2))
      return(false);
//--- prepare strings for labels
   string str_physical="Memory physical = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_PHYSICAL)+" Mb";
   string str_total="Memory total = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_TOTAL)+" Mb";
   string str_available="Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb";
   string str_used="Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb";
//--- create labels
   if(!CreateLabel(m_lbl_memory_physical,"physical_label",X_START+10,Y_START+5,str_physical,12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_memory_total,"total_label",X_START+10,Y_START+30,str_total,12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_memory_available,"available_label",X_START+10,Y_START+55,str_available,12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_memory_used,"used_label",X_START+10,Y_START+80,str_used,12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_array_type,"type_label",X_START+10,Y_START+105,"Array type = double",12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_array_size,"size_label",X_START+10,Y_START+130,"Array size = 0",12,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_error,"error_label",X_START+10,Y_START+155,"",12,clrRed))
      return(false);
   if(!CreateLabel(m_lbl_change_type,"change_type_label",X_START+10,Y_START+185,"Change type",10,clrBlack))
      return(false);
   if(!CreateLabel(m_lbl_add_size,"add_size_label",X_START+10,Y_START+210,"Add to array",10,clrBlack))
      return(false);
//--- create control elements
   if(!CreateButton(m_button_add,"add_button",X_START+15,Y_START+245,"Add",12,clrBlue))
      return(false);
   if(!CreateButton(m_button_free,"free_button",X_START+75,Y_START+245,"Free",12,clrBlue))
      return(false);
   if(!CreateComboBoxType())
      return(false);
   if(!CreateComboBoxStep())
      return(false);
//--- initialize the variable
   m_arr_size=0;
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Create the button                                                |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateButton(CButton &button,const string name,const int x,
                                  const int y,const string str,const int font_size,
                                  const int clr)
  {
//--- create the button
   if(!button.Create(m_chart_id,name,m_subwin,x,y,x+50,y+20))
      return(false);
//--- text
   if(!button.Text(str))
      return(false);
//--- font size
   if(!button.FontSize(font_size))
      return(false);
//--- label color
   if(!button.Color(clr))
      return(false);
//--- add the button to the control elements
   if(!Add(button))
      return(false);
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Create a combo box for the array size                            |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateComboBoxStep(void)
  {
//--- create the combo box
   if(!m_combo_box_step.Create(m_chart_id,"step_combobox",m_subwin,X_START+100,Y_START+185,X_START+200,Y_START+205))
      return(false);
//--- add elements to the combo box
   if(!m_combo_box_step.ItemAdd("100 000",100000))
      return(false);
   if(!m_combo_box_step.ItemAdd("1 000 000",1000000))
      return(false);
   if(!m_combo_box_step.ItemAdd("10 000 000",10000000))
      return(false);
   if(!m_combo_box_step.ItemAdd("100 000 000",100000000))
      return(false);
//--- set the current combo box element
   if(!m_combo_box_step.SelectByValue(1000000))
      return(false);
//--- add the combo box to control elements
   if(!Add(m_combo_box_step))
      return(false);
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Create a combo box for the array type                            |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateComboBoxType(void)
  {
//--- create the combo box
   if(!m_combo_box_type.Create(m_chart_id,"type_combobox",m_subwin,X_START+100,Y_START+210,X_START+200,Y_START+230))
      return(false);
//--- add elements to the combo box
   if(!m_combo_box_type.ItemAdd("char",0))
      return(false);
   if(!m_combo_box_type.ItemAdd("int",1))
      return(false);
   if(!m_combo_box_type.ItemAdd("float",2))
      return(false);
   if(!m_combo_box_type.ItemAdd("double",3))
      return(false);
   if(!m_combo_box_type.ItemAdd("long",4))
      return(false);
//--- set the current combo box element
   if(!m_combo_box_type.SelectByValue(3))
      return(false);
//--- store the current combo box element
   m_combo_box_type_value=3;
//--- add the combo box to control elements
   if(!Add(m_combo_box_type))
      return(false);
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Create a label                                                   |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateLabel(CLabel &lbl,const string name,const int x,
                                 const int y,const string str,const int font_size,
                                 const int clr)
  {
//--- create a label
   if(!lbl.Create(m_chart_id,name,m_subwin,x,y,0,0))
      return(false);
//--- text
   if(!lbl.Text(str))
      return(false);
//--- font size
   if(!lbl.FontSize(font_size))
      return(false);
//--- color
   if(!lbl.Color(clr))
      return(false);
//--- add the label to control elements
   if(!Add(lbl))
      return(false);
//--- succeed
   return(true);
  }
//+------------------------------------------------------------------+
//| Handler of clicking "Add" button event                           |
//+------------------------------------------------------------------+
void CMemoryControl::OnClickButtonAdd(void)
  {
//--- increase the array size
   m_arr_size+=(int)m_combo_box_step.Value();
//--- attempt to allocate memory for the current array
   if(CurrentArrayAdd())
     {
      //--- memory allocated, display the current status on the screen
      m_lbl_memory_available.Text("Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb");
      m_lbl_memory_used.Text("Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb");
      m_lbl_array_size.Text("Array size = "+IntegerToString(m_arr_size));
      m_lbl_error.Text("");
     }
   else
     {
      //--- failed to allocate memory, display the error message
      m_lbl_error.Text("Array is too large, error!");
      //--- return the previous array size
      m_arr_size-=(int)m_combo_box_step.Value();
     }
  }
//+------------------------------------------------------------------+
//| Handler of clicking "Free" button event                          |
//+------------------------------------------------------------------+
void CMemoryControl::OnClickButtonFree(void)
  {
//--- free the memory of the current array
   CurrentArrayFree();
//--- display the current status on the screen
   m_lbl_memory_available.Text("Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb");
   m_lbl_memory_used.Text("Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb");
   m_lbl_array_size.Text("Array size = 0");
   m_lbl_error.Text("");
  }
//+------------------------------------------------------------------+
//| Handler of the combo box change event                            |
//+------------------------------------------------------------------+
void CMemoryControl::OnChangeComboBoxType(void)
  {
//--- check if the array's type has changed
   if(m_combo_box_type.Value()!=m_combo_box_type_value)
     {
      //--- free the memory of the current array
      OnClickButtonFree();
      //--- work with another array type
      m_combo_box_type_value=(int)m_combo_box_type.Value();
      //--- display the new array type on the screen
      if(m_combo_box_type_value==0)
         m_lbl_array_type.Text("Array type = char");
      if(m_combo_box_type_value==1)
         m_lbl_array_type.Text("Array type = int");
      if(m_combo_box_type_value==2)
         m_lbl_array_type.Text("Array type = float");
      if(m_combo_box_type_value==3)
         m_lbl_array_type.Text("Array type = double");
      if(m_combo_box_type_value==4)
         m_lbl_array_type.Text("Array type = long");
     }
  }
//--- CMemoryControl class object
CMemoryControl ExtDialog;
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- create the dialog
   if(!ExtDialog.Create(0,"MemoryControl",0,X_START,Y_START,X_SIZE,Y_SIZE))
      return(INIT_FAILED);
//--- launch
   ExtDialog.Run();
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   ExtDialog.Destroy(reason);
  }
//+------------------------------------------------------------------+
//| Expert chart event function                                      |
//+------------------------------------------------------------------+
void OnChartEvent(const int id,
                  const long &lparam,
                  const double &dparam,
                  const string &sparam)
  {
   ExtDialog.ChartEvent(id,lparam,dparam,sparam);
  }


Updated: 2015.12.03