SPI_exec - Trying to access SPI_tuptable - error of 'dereferencing pointer to incomplete type'

Hi all,

I'm starting to program with the SPI interface with PG 7.0.3. I can get
everything to work up until I use SPI_exec (successfully) using a query
like 'SELECT foobar, baz1 from test1'.

The return code from SPI_exec indicates SPI_OK_SELECT and the variable
SPI_processed is 2 (meaning there are two 'results' available from the
select);

The trouble is that when I try and access the global variable
SPI_tuptable, I get the error 'dereferencing pointer to incomplete
type'.

The offending line in question in my source code is :

elog(NOTICE, "\nSPI_tuptable->alloced = %u\n\0", SPI_tuptable->alloced);

The feeling I get is something is incorrect in the header files I'm
using. So far I've been able to point to the installed include files
(/opt/postgresql/include) and have everything work. Now that I'm
getting errors I've decided to try pointing to the source code
(/install/postgresql-7.0.3/src/include and
/install/postgresql-7.0.3/src/backend) in the hope the include files are
more complete.

This is where I get the error "dereferencing pointer to incomplete type"
with the above line of code.

The exact command I'm using to compile is "gcc -fpic -shared
-I/install/postgresql-7.0.3/src/include/
-I/install/postgresql-7.0.3/src/backend
-L/install/postgresql-7.0.3/src/lib -o booking_sp_id.so booking_sp_id.c"

Can someone please give me some pointers as to what I'm doing wrong?

Regards and best wishes,

Justin Clift
Database Administrator