I am confused about PointerGetDatum among other things

Hello

I am hacking the full text indexing
c trigger found in contrib to suit my need.
(I am a C idiot having never written any
program in it)

Anyhow I have gotten all I want except
this last feature: to use a column other
than oid.

I have the following added

char *id;
..
colnum=SPI_fnumber(tupdesc,args[2]);
id=SPI_getvalue(rettuple,tupdesc,colnum);

I have also verified that id contains the column
I want by doing
elog(ERROR,id);
and it does

Now the original author uses
Datum values[2];
to insert the data and he has
values[0] = PointerGetDatum(data);
before he does
ret = SPI_execp(*(plan->splan), values, NULL, 0);

So I tried something
values[1]=PointerGetDatum(id);
as well as other variations without that
function.

Thanks in advance for any help