}
+function chat_get_participants($chatid) {
+//Returns the users with data in one chat
+//(users with records in chat_messages, students)
+
+ global $CFG;
+
+ //Get students
+ $students = get_records_sql("SELECT DISTINCT u.*
+ FROM {$CFG->prefix}user u,
+ {$CFG->prefix}chat_messages c
+ WHERE c.chatid = '$chatid' and
+ u.id = c.userid");
+
+ //Return students array (it contains an array of unique users)
+ return ($students);
+}
+
?>