connected standby

参考链接

https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/modern-standby

https://blogs.msdn.microsoft.com/winsdk/2014/12/02/how-to-get-notified-when-going-in-and-out-of-connected-standby-from-a-windows-service/

一 介绍

　　低功耗联网状态, win8 win8.1叫connected standby, win10 对win8的connected standby 进行了扩展, 并起了一个新名字,叫modern-standby

　　进入这种状态时，Windows Store Applications以及传统桌面程序会被暂停, session 0中的服务程序不会被暂停, 但是会受到一些限制(目前没有详细测试, 会受到哪些限制)

　　只有硬件跟系统都支持的时候, 这台机器才支持这种状态

二 查看是否支持这种状态

　　以win10为例, 使用命令powercfg /a之后, 如果有 so 低电量待机字样的说明当前机器支持这种状态

　　

三 查看当前系统何时进入这种状态

还是以win10为例, 使用命令 powercfg /batteryreport, 成功执行后会在当前目录生成一份电池使用报告, 部分报告如下所示

四 程序感知系统进入跟离开这种状态

在第二个url中有详细的方法, 测试服务通知的时候发现有一些细节需要注意, 参见代码中的注释, 关键代码如下:

 #include <PowrProf.h>
 #pragma comment(lib,"PowrProf.lib")
 #include <WinNT.h>

 SERVICE_STATUS_HANDLE hStatus = NULL;
 VOID WINAPI ServiceMain(DWORD   dwNumServicesArgs, LPWSTR  *lpServiceArgVectors)
 {
 //省略的代码

 //为服务注册控制处理器
     hStatus = RegisterServiceCtrlHandlerEx(L"aaa", Ctrlhandler, NULL);//服务名，指向controlhandlefunction指针
     if (!hStatus)
     {
         return;
     }

 //省略的代码

     WriteLog("service start");
     // 针对connected standby的特殊处理
     HPOWERNOTIFY hNotify = NULL;
     if (IsSupportConnectedStandby())
     {
         hNotify =RegisterPowerSettingNotification(hStatus, &GUID_MONITOR_POWER_ON, DEVICE_NOTIFY_SERVICE_HANDLE);
         if (!hNotify)
             WriteLog("register err!!!!");
         else
             WriteLog("register success");
     }

 //省略的代码

     // 服务主线程结束时, 要取消掉通知回调
     if (hNotify)
         UnregisterPowerSettingNotification(hNotify);
35 }    

 bool IsSupportConnectedStandby()//S0 low power idle
 {
     bool result = false;
     do
     {
         SYSTEM_POWER_CAPABILITIES info = {  };
         NTSTATUS ret = CallNtPowerInformation(SystemPowerCapabilities, NULL, , &info, sizeof(info));
         if (ret != )//STATUS_SUCCESS 用户层没有这个宏, 所以直接用数值进行比较
         {
             printf("get info error: %x\n", ret);
             break;
         }
         if (info.AoAc == TRUE)
             result = true;
     } while (false);

     return result;
 }

 DWORD WINAPI Ctrlhandler(DWORD dwControl, DWORD dwEventType, LPVOID lpEventData, LPVOID lpContext)
 {
     switch (dwControl)
     {
     case SERVICE_CONTROL_STOP:
         brun = false;
         ServiceStatus.dwCurrentState = SERVICE_STOPPED;
         WriteLog("SERVICE_CONTROL_STOP");
         break;
     case SERVICE_CONTROL_SHUTDOWN:
         brun = false;
         ServiceStatus.dwCurrentState = SERVICE_STOPPED;
         WriteLog("SERVICE_CONTROL_SHUTDOWN");
         break;
     case SERVICE_CONTROL_PAUSE:
         brun = false;
         ServiceStatus.dwCurrentState = SERVICE_PAUSED;
         WriteLog("SERVICE_CONTROL_SHUTDOWN");
         break;
     case SERVICE_CONTROL_CONTINUE:
         brun = false;
         ServiceStatus.dwCurrentState = SERVICE_RUNNING;
         break;
     case SERVICE_CONTROL_POWEREVENT:
         switch (dwEventType)
         {
         case PBT_APMRESUMEAUTOMATIC:
         {
             WriteLog("PBT_APMRESUMEAUTOMATIC");
             break;
         }
         case PBT_APMRESUMESUSPEND:
         {
             WriteLog("PBT_APMRESUMESUSPEND");
             break;
         }
         case PBT_APMSUSPEND:
         {
             WriteLog("PBT_APMSUSPEND");
             break;
         }
         case PBT_APMPOWERSTATUSCHANGE: // 交流变电池 或者电池变交流
         {
             WriteLog("PBT_APMPOWERSTATUSCHANGE");
             break;
         }
         case PBT_POWERSETTINGCHANGE:
         {
             WriteLog("PBT_POWERSETTINGCHANGE");
             PPOWERBROADCAST_SETTING setting = (PPOWERBROADCAST_SETTING)lpEventData;
             if(setting->PowerSetting == GUID_MONITOR_POWER_ON)
             {
                 std::string str("GUID_MONITOR_POWER_ON ");

                 if(setting->DataLength == )
                 {
                     // MONITOR_POWER_OFF(data ==0)-->进入 connected standby状态
                     // MONITOR_POWER_ON(data ==1)-->进入 active状态
                     // MONITOR_POWER_OFF对应于设置里面睡眠进入的时间, 而不是根据字面意思对应设置里面的屏幕关闭时间, 这个要注意!!!
                     // 刚刚注册GUID_MONITOR_POWER_ON成功后会立刻收到一次该事件, 报告data ==1
                     DWORD data = *(DWORD*)(setting->Data);
                     str += std::to_string(data);
                 }
                 else
                 {
                     str += "len: ";
                     str += std::to_string(setting->DataLength);
                 }
                 WriteLog(str);
             }
             break;
         }

         default:
             break;
         }
         break;
     case SERVICE_CONTROL_SESSIONCHANGE:
     {
         std::string str("SERVICE_CONTROL_SESSIONCHANGE: ");
         str+= std::to_string(dwEventType);

         PWTSSESSION_NOTIFICATION Notification = (PWTSSESSION_NOTIFICATION)lpEventData;
         str += " ";
         str += std::to_string(Notification->dwSessionId);
         WriteLog(str.c_str());

         switch (dwEventType)
         {
         case WTS_CONSOLE_CONNECT:
             break;
         case WTS_CONSOLE_DISCONNECT:
             break;
         case WTS_SESSION_LOGON:
             break;
         case WTS_SESSION_LOGOFF:
             break;
         case WTS_SESSION_LOCK:
             break;
         case WTS_SESSION_UNLOCK:
             break;
         default:
             ;
         }
     }
         break;
     default:
         break;
     }
     //向SCM报告“SERVICE_STOPPED”状态
     SetServiceStatus(hStatus, &ServiceStatus);
     return NO_ERROR;
 }