C-Function: Returning Rows

hi,

I have a C Function that returns a row. The following was used to
create the function (some code omitted):

CREATE TYPE __Result AS (status integer, last_response integer);
CREATE OR REPLACE FUNCTION my_function(...) RETURNS __Result ...

in my function I have the following:
TupleDesc tup_descriptor;
Datum dat_values[2];
HeapTuple heap_tuple;
bool *pNulls;

get_call_result_type(fcinfo, NULL, &tup_descriptor);
BlessTupleDesc(tup_descriptor);
dat_values[0] = Int32GetDatum(50);
dat_values[1] = Int32GetDatum(20);
iTup_Length = tup_descriptor->natts;
pNulls = palloc(iTup_Length * sizeof(bool));
heap_tuple = heap_form_tuple(tup_descriptor, dat_values, pNulls);
PG_RETURN_DATUM(HeapTupleGetDatum(heap_tuple));

Calling the function works as expected but the return values (row) is
not correct, there is some problems. Sometimes when I call the
function I get:
my_function
--------------
(50,20)
(1 row)

and other times I get:
my_function
--------------
(,)
(1 row)

and I have seen:
my_function
--------------
(50,)
(1 row)

Am I doing something wrong in my function that would have this affect?

I do not want to return the hard coded values but rather variables in
my function, this is for testing.

PostgreSQL 8.4 on Ubuntu 10.04
--
Carel Combrink
s25291930(at)tuks(dot)co(dot)za

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