diff --git a/reference/filter/functions/filter-var.xml b/reference/filter/functions/filter-var.xml
index ae515048e7..12cfdee46e 100644
--- a/reference/filter/functions/filter-var.xml
+++ b/reference/filter/functions/filter-var.xml
@@ -69,15 +69,17 @@ $var = filter_var('oops', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
 $var = filter_var('oops', FILTER_VALIDATE_BOOLEAN,
                   array('flags' => FILTER_NULL_ON_FAILURE));
 
-// callback filter
+// callback validate filter
 function foo($value)
 {
-    $ret = new stdClass;
-    $ret->value = filter_var($value, FILTER_VALIDATE_BOOLEAN,
-                             array('flags' => FILTER_NULL_ON_FAILURE));
-    return $ret;
+    // Expected format: Surname, GivenNames
+    list($surname, $givennames) = explode(", ", $value, 2);
+    if(
+        !(empty($surname) || empty($givennames))
+        && (is_string($surname) && is_string($givennames))
+      ) return $value; else return false;
 }
-$var = filter_var('yes', FILTER_CALLBACK, array('options' => 'foo'));
+$var = filter_var('Doe, Jane Sue', FILTER_CALLBACK, array('options' => 'foo'));
 ?>
         ]]>
        </programlisting>