how to get tuple - Mailing list pgsql-hackers

Hello,

I'm new in postgreSQL programming. I try to print a tuple from 
tupleTableSlot structure..
for example..

outerTupleSlot = ExecHashJoinOuterGetTuple(outerNode,                                                           node,
&hashvalue);

how to extract a tuple value?

there are any kind of documentation about that?

Regards.