UDTF column return methods

You can use the following methods to return multiple columns in a UDTF:
int numReturnColumns();
int returnTypeColumn(int n);
void setReturnColumnNull(int n, bool val);
struct Interval* intervalReturnColumn(int n);
Numeric32Val* numeric32ReturnColumn(int n);
Numeric64Val* numeric64ReturnColumn(int n);
Numeric128Val* numeric128ReturnColumn(int n);
TimeTzADT* timetzReturnColumn(int n);    
StringReturn* stringReturnColumn(int n);
float* floatReturnColumn(int n); 
double* doubleReturnColumn(int n);
int8* int8ReturnColumn(int n);
int16* int16ReturnColumn(int n);
int32* int32ReturnColumn(int n);
int64* int64ReturnColumn(int n);
int32* dateReturnColumn(int n);
int64* timeReturnColumn(int n);
int64* timestampReturnColumn(int n);
bool isReturnColumnNull(int n);