Use empty istead of isset

htdocs/admin/const.php

@@ -19,10 +19,10 @@
  */
 
 /**
- \file       htdocs/admin/const.php
- \ingroup    setup
- \brief      Page d'administration/configuration des constantes autres
- \version    $Id$
+ *	\file       htdocs/admin/const.php
+ *	\ingroup    setup
+ *	\brief      Admin page to defined miscellaneous constants
+ *	\version    $Id$
  */
 
 require("./pre.inc.php");
@@ -36,6 +36,10 @@ accessforbidden();
 
 $typeconst=array('yesno','texte','chaine');
 
+/*
+ * Actions
+ */
+
 if ($_POST["action"] == 'update' || $_POST["action"] == 'add')
 {
 	if (! dolibarr_set_const($db, $_POST["constname"],$_POST["constvalue"],$typeconst[$_POST["consttype"]],1,isset($_POST["constnote"])?$_POST["constnote"]:'',$_POST["entity"]));
@@ -53,6 +57,10 @@ if ($_GET["action"] == 'delete')
 }
 
 
+/*
+ * View
+ */
+
 llxHeader();
 
 print_fiche_titre($langs->trans("OtherSetup"),'','setup');
@@ -113,7 +121,7 @@ $sql.= ", note";
 $sql.= ", entity";
 $sql.= " FROM ".MAIN_DB_PREFIX."const";
 $sql.= " WHERE entity IN (0,".$conf->entity.")";
-if (!isset($all)) $sql.= " AND visible = 1";
+if (!empty($all)) $sql.= " AND visible = 1";
 $sql.= " ORDER BY name ASC";
 
 dol_syslog("Const::listConstant sql=".$sql);