Provides opening of Depth of Market for a selected symbol, and subscribes for receiving notifications of the DOM changes.
[in] The name of a symbol, whose Depth of Market is to be used in the Expert Advisor or script.
The true value if opened successfully, otherwise false.
Normally, this function must be called from the OnInit() function or in the class constructor. To handle incoming alerts, in the Expert Advisor program must contain the function void OnBookEvent(string& symbol).