scalar-setting-null-c-.md

The following C++ example demonstrates setting the null behavior of Add2ints so Vertica does not call the function with NULL values.

class Add2intsNullOnNullInputFactory : public Vertica::ScalarFunctionFactory
{
    virtual Vertica::ScalarFunction *createScalarFunction(Vertica::ServerInterface &srvInterface)
    { return vt_createFuncObj(srvInterface.allocator, Add2ints); }
    virtual void getPrototype(Vertica::ServerInterface &srvInterface,
                              Vertica::ColumnTypes &argTypes,
                              Vertica::ColumnTypes &returnType)
    {
        argTypes.addInt();
        argTypes.addInt();
        returnType.addInt();
    }

public:
    Add2intsNullOnNullInputFactory() {strict = RETURN_NULL_ON_NULL_INPUT;}
};
RegisterFactory(Add2intsNullOnNullInputFactory);