Question re: null

I have written a function that will return an integer based on the length
of a given field defined as text.
It seems that if the given field has not yet been populated (ie: it is
null), my function returns nothing.  I have tried expressly sending back a
value as such to no avail:

int isempty(text*)
{
  return (100);
}

If the text* is null, it does not return 100 though it does seem to
process the function and does not core dump.  (ie: returns blank entries
with the proper number of tuples at the end).  Any ideas?  Thanks again.

--
Colin Dick
On Call Internet Services
cdick@mail.ocis.net