diff --git a/reference/exec/functions/proc-open.xml b/reference/exec/functions/proc-open.xml
index 35e404b8fc..ada28d3ff8 100644
--- a/reference/exec/functions/proc-open.xml
+++ b/reference/exec/functions/proc-open.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.17 $ -->
+<!-- $Revision: 1.18 $ -->
 <!-- splitted from ./en/functions/exec.xml, last change in rev 1.28 -->
   <refentry xml:id='function.proc-open' xmlns="http://docbook.org/ns/docbook">
    <refnamediv>
@@ -60,8 +60,20 @@
        process. 0 is stdin, 1 is stdout, while 2 is stderr.
       </para>
       <para>
-       The currently supported pipe types are <literal>file</literal> and
-       <literal>pipe</literal> <!-- and <literal>pty</literal>-->.
+       Each element can be:
+       <simplelist>
+        <member>An array describing the pipe to pass to the process. The first
+         element is the descriptor type and the second element is an option for
+         the given type. Valid types are <literal>pipe</literal> (the second
+         element is either <literal>r</literal> to pass the read end of the pipe
+         to the process, or <literal>w</literal> to pass the write end) and
+         <literal>file</literal> (the second element is a filename).
+        </member>
+        <member>
+         A stream resource representing a real file descriptor (e.g. opened file,
+         a socket, <constant>STDIN</constant>).
+        </member>
+       </simplelist>
       </para>
       <para>
        The file descriptor numbers are not limited to 0, 1 and 2 - you may