A PHP Error was encountered

Severity: Notice

Message: Only variable references should be returned by reference

Filename: core/Common.php

Line Number: 257

Fatal error: Uncaught Error: Call to undefined function mysql_pconnect() in /var/www/vhosts/khanpak.com/httpdocs/system/database/drivers/mysql/mysql_driver.php:91 Stack trace: #0 /var/www/vhosts/khanpak.com/httpdocs/system/database/DB_driver.php(115): CI_DB_mysql_driver->db_pconnect() #1 /var/www/vhosts/khanpak.com/httpdocs/system/database/DB.php(148): CI_DB_driver->initialize() #2 /var/www/vhosts/khanpak.com/httpdocs/system/core/Loader.php(338): DB(Array, NULL) #3 /var/www/vhosts/khanpak.com/httpdocs/application/models/content_model.php(18): CI_Loader->database('db1', true) #4 /var/www/vhosts/khanpak.com/httpdocs/system/core/Loader.php(303): Content_model->__construct() #5 /var/www/vhosts/khanpak.com/httpdocs/system/core/Loader.php(237): CI_Loader->model('Content_model') #6 /var/www/vhosts/khanpak.com/httpdocs/system/core/Loader.php(1185): CI_Loader->model(Array) #7 /var/www/vhosts/khanpak.com/httpdocs/system/core/Loader.php(152): CI_Loader->_ci_autoloader() #8 /var/www/vhosts/khanpak.com/httpdocs/system/core/Controller. in /var/www/vhosts/khanpak.com/httpdocs/system/database/drivers/mysql/mysql_driver.php on line 91