[in] Position symbol. If the symbol isn't specified, the current symbol will be used.
[in] Price. If the price isn't specified, the current market Ask price will be used.
[in] Stop Loss price.
[in] Take Profit price.
true - in case of successful check of the structures, otherwise - false.
Successful completion of the Buy(...) method does not always mean successful execution of the trade operation. It's necessary to check the result of trade request (trade server return code) using ResultRetcode() and value, returned by ResultDeal().