UCTNAME"
>PGconn</TT
>.  The passthrough pointer never changes for the
   life of the <TT
CLASS="STRUCTNAME"
>PGconn</TT
> and all <TT
CLASS="STRUCTNAME"
>PGresult</TT
>s
   generated from it; so if used, it must point to long-lived data.
   In addition there is an <I
CLASS="FIRSTTERM"
>instance data</I
> pointer, which starts
   out <TT
CLASS="SYMBOL"
>NULL</TT
> in every <TT
CLASS="STRUCTNAME"
>PGconn</TT
> and <TT
CLASS="STRUCTNAME"
>PGresult</TT
>.
   This pointer can be manipulated using the
   <CODE
C