diff --git a/reference/filesystem/functions/fseek.xml b/reference/filesystem/functions/fseek.xml
index 05b42938d5..46b5454c4a 100644
--- a/reference/filesystem/functions/fseek.xml
+++ b/reference/filesystem/functions/fseek.xml
@@ -101,16 +101,17 @@ fseek($fp, 0);
   &reftitle.notes;
   <note>
    <para>
-    If you have opened the file in append ("a" or "a+") mode, any data you write
-    to the file will always be appended, regardless of the file position.
+    If you have opened the file in append (<literal>a</literal> or
+    <literal>a+</literal>) mode, any data you write to the file will always be
+    appended, regardless of the file position, and the result of calling
+    <function>fseek</function> will be undefined.
    </para>
   </note>
   <note>
    <para>
-    May not be used on file pointers returned by
-    <function>fopen</function> if they use the "http://" or "ftp://"
-    formats. <function>fseek</function> gives also undefined results for
-    append-only streams (opened with "a" flag).
+    May not be used on file pointers returned by <function>fopen</function> if
+    they use the <literal>http://</literal> or <literal>ftp://</literal>
+    schemes.
    </para>
   </note>
  </refsect1>