 if the corresponding parameter
      value is null.  (In the latter case, the actual value in the
      corresponding <TT
CLASS="PARAMETER"
>values</TT
> entry doesn't matter.)  Note
      that <TT
CLASS="PARAMETER"
>nulls</TT
> is not a text string, just an array:
      it does not need a <TT
CLASS="LITERAL"
>'\0'</TT
> terminator.
     </P
></DD
><DT
><TT
CLASS="LITERAL"
>bool <TT
CLASS="PARAMETER"
>read_only</TT
></TT
></DT
><DD
><P
><TT
CLASS="LITERAL"
>true</TT
> for read-only execution</P
></DD
><DT
