Does the OPER contain a boolean?
[C++]
BOOL IsBool() const;
Returns TRUE if the COper contains an boolean value, FALSE otherwise.
Header: xllplus.h
COper Class 
					  | COper Methods			 
					  | COper::IsArray()			 
					  | COper::IsDouble()			 
					  | COper::IsError()			 
					  | COper::IsString()			 
					  | COper::IsEmpty()			 
					  | COper::IsMissing()			 
					  | COper::IsPresent()