diff --git a/reference/filesystem/functions/fseek.xml b/reference/filesystem/functions/fseek.xml
index 96942dea15..1a664b9abd 100644
--- a/reference/filesystem/functions/fseek.xml
+++ b/reference/filesystem/functions/fseek.xml
@@ -40,8 +40,10 @@
        The offset.
       </para>
       <para>
-       To move to a position before the end-of-file, you need to pass a negative
-       value in <parameter>offset</parameter>.
+       To move to a position before the end-of-file, you need to pass
+       a negative value in <parameter>offset</parameter> and
+       set <parameter>whence</parameter>
+       to <constant>SEEK_END</constant>.
       </para>
      </listitem>
     </varlistentry>