下列常量由此擴展定義，且僅在此擴展編譯入 PHP 或在運行時(shí)動(dòng)態(tài)載入時(shí)可用。
YAR_VERSION
(string)
YAR_CLIENT_PROTOCOL_HTTP
(integer)
YAR_CLIENT_OPT_PACKAGER
(integer)
YAR_CLIENT_OPT_TIMEOUT
(integer)
YAR_CLIENT_OPT_CONNECT_TIMEOUT
(integer)
YAR_PACKAGER_PHP
(string)
YAR_PACKAGER_JSON
(string)
YAR_ERR_OKEY
(integer)
YAR_ERR_OUTPUT
(integer)
YAR_ERR_TRANSPORT
(integer)
YAR_ERR_REQUEST
(integer)
YAR_ERR_PROTOCOL
(integer)
YAR_ERR_PACKAGER
(integer)
YAR_ERR_EXCEPTION
(integer)