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