Merge remote-tracking branch 'donkult/debian/sid' into debian/sid

1 files changed, 11 insertions, 2 deletions

diff --git a/doc/apt.conf.5.xml b/doc/apt.conf.5.xml
index f5e1f966d..42119baa5 100644
--- a/doc/apt.conf.5.xml
+++ b/doc/apt.conf.5.xml
@@ -688,7 +688,8 @@ DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
      <literal>options</literal> this must be specified in list notation. The commands
      are invoked in order using <filename>/bin/sh</filename>; should any fail APT 
      will abort. APT will pass the filenames of all .deb files it is going to
-     install to the commands, one per line on standard input.</para>
+     install to the commands, one per line on the requested file descriptor, defaulting
+     to standard input.</para>
 
      <para>Version 2 of this protocol dumps more information, including the
      protocol version, the APT configuration space and the packages, files
@@ -700,7 +701,15 @@ DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
      <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::Version</literal>
      accordingly, the default being version 1. If APT isn't supporting the requested
      version it will send the information in the highest version it has support for instead.
-     </para></listitem>
+     </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>
      </varlistentry>
 
      <varlistentry><term><option>Run-Directory</option></term>