I've got the IB6 pdf but is there anything better or more recent?

what I'm trying to do is call a selectable SP, from C, passing in 1 paramenter.

the sql looks like "select a, b from mysp ( ? )"

I setup 2 xsqlca areas, call
isc_start_transaction, #
isc_dsql_allocate_statement,
isc_dsql_prepare (passing output xsqlca)
isc_dsql_describe_bind (passing input xsqlca)
isc_dsql_execute2(passing both input & output xsqlc)
at this point I get an error
Invalid token
SQL error code = -104
- Unexpected end of command