php手册:
http://www.php.net/manual/zh/features.gc.refcounting-basics.php
http://www.php.net/manual/zh/features.gc.collecting-cycles.php
http://www.php.net/manual/zh/features.gc.performance-considerations.php
php手册:
http://www.php.net/manual/zh/features.gc.refcounting-basics.php
http://www.php.net/manual/zh/features.gc.collecting-cycles.php
http://www.php.net/manual/zh/features.gc.performance-considerations.php