Hugo,

Thanks for your comments. My understanding of the syntax "Do myfun with VAR [, VAR ... ]" is that it forces the passing of variables by reference regardless of the setting of 'SET UDFPARMS'. Do you have a different interpretation?

I appreciate your comments about enclosing variables in parentheses (VAR) to force VFP to pass the variable's value by value vs. reference. Forgot about that trick!

Regards,
Malcolm

>Malcolm,
>
>I dont have any new additions, just a comment.
>
>>- Do myfun with VAR [, VAR ... ] // forces variables to be passed by reference
>
>This is partially true, it will depend on:
>Setting of UDFPARMS
>parameters being actual variables, no expresions
>parameters not enclosed in parenthesis