Returns the requested property of a deal. The deal property must be of the double type. There are 2 variants of the function.
1. Immediately returns the property value.
2. Returns true or false, depending on the success of the function. If successful, the value of the property is placed into a target variable passed by reference by the last parameter.
[in] Deal ticket.
[in] Identifier of a deal property. The value can be one of the values of the ENUM_DEAL_PROPERTY_DOUBLE enumeration.
[out] Variable of the double type that accepts the value of the requested property.
Value of the double type.