This function is used to set the Session Module at site or script level.
The global configuration can be done in php.ini under the [Session] section and with the name of "session.save_handler". The sessions are saved in files by default, like so:
session.save_handler = files
But with this configuration you set one of your websites to use some other session module (if you have them installed and extension loaded with PHP), like so:
<?php
session_module_name('memcache'); session_save_path('localhost:11211'); session_save_path('localhost:11211:41,otherhost:11211:60') echo session_module_name(); if(session_module_name() != 'memcache'){
}