diff --git a/reference/filesystem/functions/tempnam.xml b/reference/filesystem/functions/tempnam.xml
index 4243618c0c..54f2978be3 100644
--- a/reference/filesystem/functions/tempnam.xml
+++ b/reference/filesystem/functions/tempnam.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.4 $ -->
+<!-- $Revision: 1.5 $ -->
 <!-- splitted from ./en/functions/filesystem.xml, last change in rev 1.2 -->
   <refentry id="function.tempnam">
    <refnamediv>
@@ -29,6 +29,12 @@
      points to exists. Consult your system documentation on the
      tempnam(3) function if in doubt.
     </para>
+    <note>
+     <simpara>
+      If PHP cannot create a file in the specified <parameter>dir</parameter>
+      parameter, it falls back on the system default.
+     </simpara>
+    </note>
     <para>
      Returns the new temporary filename, or the &false; string on
      failure.