预定义常量
PHP Manual

Win32Service Service Control Message Accepted Bitmasks
Constant Value Description
WIN32_SERVICE_ACCEPT_PAUSE_CONTINUE 0x00000002 The service can be paused and continued. This control code allows the service to receive WIN32_SERVICE_CONTROL_PAUSE and WIN32_SERVICE_CONTROL_CONTINUE notifications.
WIN32_SERVICE_ACCEPT_PRESHUTDOWN 0x00000100 The service can perform preshutdown tasks. This control code enables the service to receive WIN32_SERVICE_CONTROL_PRESHUTDOWN notifications. This value is not supported by Windows Server 2003 and Windows XP/2000.
WIN32_SERVICE_ACCEPT_SHUTDOWN 0x00000004 The service is notified when system shutdown occurs. This control code allows the service to receive WIN32_SERVICE_CONTROL_SHUTDOWN notifications.
WIN32_SERVICE_ACCEPT_STOP 0x00000001 The service can be stopped. This control code allows the service to receive WIN32_SERVICE_CONTROL_STOP notifications.

预定义常量
PHP Manual