定義済み定数
PHP Manual

Win32Service サービス制御メッセージ定数
定数 説明
WIN32_SERVICE_CONTROL_CONTINUE 0x00000003 Notifies a paused service that it should resume.
WIN32_SERVICE_CONTROL_INTERROGATE 0x00000004 Notifies a service that it should report its current status information to the service control manager.
WIN32_SERVICE_CONTROL_PAUSE 0x00000002 Notifies a service that it should pause.
WIN32_SERVICE_CONTROL_PRESHUTDOWN 0x0000000F Notifies a service that the system will be shutting down. A service that handles this notification blocks system shutdown until the service stops or the preshutdown time-out interval expires. This value is not supported by Windows Server 2003 and Windows XP/2000.
WIN32_SERVICE_CONTROL_SHUTDOWN 0x00000005 Notifies a service that the system is shutting down so the service can perform cleanup tasks. If a service accepts this control code, it must stop after it performs its cleanup tasks. After the SCM sends this control code, it will not send other control codes to the service.
WIN32_SERVICE_CONTROL_STOP 0x00000001 Notifies a service that it should stop.

定義済み定数
PHP Manual