以下常量由此扩展定义，只有在将扩展编译到PHP中或在运行时动态加载时才可用。
VARNISH_STATUS_SYNTAX (int)VARNISH_STATUS_UNKNOWN (int)VARNISH_STATUS_UNIMPL (int)VARNISH_STATUS_TOOFEW (int)VARNISH_STATUS_TOOMANY (int)VARNISH_STATUS_PARAM (int)VARNISH_STATUS_AUTH (int)VARNISH_STATUS_OK (int)VARNISH_STATUS_CANT (int)VARNISH_STATUS_COMMS (int)VARNISH_STATUS_CLOSE (int)VARNISH_CONFIG_IDENT (string)VARNISH_CONFIG_HOST (string)VARNISH_CONFIG_PORT (string)VARNISH_CONFIG_TIMEOUT (string)VARNISH_CONFIG_SECRET (string)VARNISH_CONFIG_COMPAT (string)VARNISH_COMPAT_2 (int)VARNISH_COMPAT_3 (int)