>>>>Hi Vlad,
>>>>
>>>>My guess is that TYPE() function doesn't evaluate UDF's for performance reason.
>>>
>>>And how about side-effects? The UDF might do almost anything.
>>
>>I agree with your analysis. The UDF could be called with a reference parameter, and in fact return nothing at all in the normal sense.
>
>Yes, but apart from return-values, I meant that the function might have undesirable side effects. That is, apart from returning a value, the UDF might change the environment, close the application, delete data, etc.
>
>Hilmar.

I figured that was what you meant.

I just wanted to point out a very obvious situation in which things get changed even if no return value happens. Clearly one would not want current variables changed just to check the return type of a UDF.

Alan