//增加用户
function AddUser($username){
global $db;
$Ip=getenv(‘REMOTE_ADDR‘);
$Ip1 = getenv(‘HTTP_X_FORWARDED_FOR‘);
if (($Ip1 != "") && ($Ip1 != "unknown")) $Ip=$Ip1;
$current_time=date("Y-m-d H:i:s");
$SQL="select user from class_online where user=‘$username‘";
$res=mysql_query($SQL,$db);
$row=@mysql_num_rows($res);
if($row==0) {
$SQL="insert into class_online (user,ip,lasttime) values(‘$username‘,‘$Ip‘,‘$current_time‘)";
mysql_query($SQL,$db);
}
}
//更新在线用户名单
function UpdateMember(){
global $db;
$SQL="delete from class_online where UNIX_TIMESTAMP()-UNIX_TIMESTAMP(lasttime)>180"; //3分钟不活动则退出
//echo $SQL;
mysql_query($SQL,$db);
}
//更新在线状态
function UpdateOnline($username){
global $db;
$current_time=date("Y-m-d H:i:s");;
$SQL="update class_online set lasttime=‘$current_time‘ where user=‘$username‘";
$res=mysql_query($SQL,$db);
}
//删除用户
function OutOneUser($user){
global $db;
$SQL="delete from class_online where user=‘$user‘";
mysql_query($SQL,$db);
return true;
}
//检查是否在线
function CheckUser($user){
global $db;
$SQL="select user from class_online where user=‘$user‘";
$res=mysql_query($SQL,$db);
$row=mysql_num_rows($res);
if($row>0) return true;
else return false;
}
//取在线名单
function ReadOnlineName(){
global $db;
$SQL="select * from class_online";
$res=mysql_query($SQL,$db);
while($row=mysql_fetch_array($res)){
$result[]=$row[user];
}
return $result;
}
//********************在线人员函数库***************end php实现的在线人员函数库
原文：http://www.jb51.net/article/14124.htm
