diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index ebd5cb98a76..9503404350c 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -3475,6 +3475,17 @@ abstract class CommonObject
     	return $result;
     }
 
+	/**
+	 * Common function for all objects extending CommonObject for generating documents
+	 *
+	 * @param string $modelspath Relative folder where models are placed
+	 * @param string $modele Model to use
+	 * @param Translate $outputlangs Language to use
+	 * @param int $hidedetails 1 to hide details. 0 by default
+	 * @param int $hidedesc 1 to hide product description. 0 by default
+	 * @param int $hideref 1 to hide product reference. 0 by default
+	 * @return int 1 if OK -1 if not OK
+	 */
 	protected function commonGenerateDocument($modelspath, $modele, $outputlangs, $hidedetails, $hidedesc, $hideref)
 	{
 		global $conf, $langs;