+ </para>
+
+ <para>The file descriptor to be used to send the information can be requested with
+ <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::InfoFD</literal>
+ which defaults to <literal>0</literal> for standard input and is available since
+ version 0.9.11. Support for the option can be detected by looking for the environment
+ variable <envar>APT_HOOK_INFO_FD</envar> which contains the number of the used
+ file descriptor as a confirmation.</para>
+ </listitem>