MQL5 ReferenceMarket InfoMarketBookRelease

MarketBookRelease

Provides closing of Depth of Market for a selected symbol, and cancels the subscription for receiving notifications of the DOM changes.

bool  MarketBookRelease(
   string  symbol      // symbol
   );

Parameters

symbol

[in] Symbol name.

Return Value

The true value if closed successfully, otherwise false.

Note

Normally, this function must be called from the OnDeinit() function, if the corresponding MarketBookAdd() function has been called in the OnInit() function. Or it must be called from the class destructor, if the corresponding MarketBookAdd() function has been called from the class constructor.

Example:

#define SYMBOL_NAME "GBPUSD"

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//--- open the market depth for SYMBOL_NAME symbol
   if(!MarketBookAdd(SYMBOL_NAME))
     {
      PrintFormat("MarketBookAdd(%s) failed. Error ", SYMBOL_NAME, GetLastError());
      return;
     }

//--- send the message about successfully opening the market depth to the journal
   PrintFormat("The MarketBook for the '%s' symbol was successfully opened and a subscription to change it was received", SYMBOL_NAME);

//--- wait 2 seconds
   Sleep(2000);

//--- upon completion, unsubscribe from the open market depth
//--- send the message about successfully unsubscribing from the market depth or about the error to the journal
   ResetLastError();
   if(MarketBookRelease(SYMBOL_NAME))
      PrintFormat("MarketBook for the '%s' symbol was successfully closed", SYMBOL_NAME);
   else
      PrintFormat("Error %d occurred when closing MarketBook using the '%s' symbol", GetLastError(), SYMBOL_NAME);

   /*
   result:
   The MarketBook for the 'GBPUSD' symbol was successfully opened and a subscription to change it was received
   MarketBook for the 'GBPUSD' symbol was successfully closed
   */
  }