利用 WindowProc 监控PC Power状态

msdn 说明： https://docs.microsoft.com/zh-cn/windows/desktop/Power/wm-powerbroadcast

LRESULT CALLBACK WindowProc(
  HWND   hwnd,    // handle to window
  UINT   uMsg,    // WM_POWERBROADCAST
  WPARAM wParam,  // power-management event
  LPARAM lParam   // function-specific data
);

Parameters

hwnd

A handle to window.

*uMsg*

Value	Meaning
WM_POWERBROADCAST 536 (0x218)	Message identifier.

wParam

The power-management event. This parameter can be one of the following event identifiers.

Event	Meaning
PBT_APMPOWERSTATUSCHANGE 10 (0xA)	Power status has changed.
PBT_APMRESUMEAUTOMATIC 18 (0x12)	Operation is resuming automatically from a low-power state. This message is sent every time the system resumes.
PBT_APMRESUMESUSPEND 7 (0x7)	Operation is resuming from a low-power state. This message is sent after PBT_APMRESUMEAUTOMATIC if the resume is triggered by user input, such as pressing a key.
PBT_APMSUSPEND 4 (0x4)	System is suspending operation.
PBT_POWERSETTINGCHANGE 32787 (0x8013)	A power setting change event has been received.

lParam

The event-specific data. For most events, this parameter is reserved and not used.

If the wParam parameter is PBT_POWERSETTINGCHANGE, the lParam parameter is a pointer to a POWERBROADCAST_SETTING structure.

Return value

An application should return TRUE if it processes this message.

通过监视PC Power状态，实现应用程序在不同Power状态下对应的行为。