PHP imitates asp Application object online people counting implementation method, application object_PHP tutorial

/*
Usage:
application('key','value'); //Set key=value
$value = application('key'); //Get the value of key
*/

function application()
{
$args = func_get_args(); //Get input parameters
if (count($args) >2 || count($args) < 1) return;
$ssid = session_id(); //Save the current session_id
session_write_close(); //End the current session
ob_start(); //Disable global session from sending header
session_id("xxx"); //Register global session_id
session_start(); //Open global session
$key = $args[0];
if (count($args) == 2) //If there is a second parameter, it means writing to the global session
{
$re = ($_session[$key] = $args[1]);
}
else // If there is only one parameter, then return the value corresponding to the parameter
{
$re = $_session[$key];
}
session_write_close(); //End global session
session_id($ssid); //Re-register the interrupted non-global session
session_start(); //Restart
ob_end_clean(); //Discard some header output just generated by session_start
return $re;
}