WinCE下监视设备插拔的参考代码

      在一些项目中，系统需要实时监测U盘或SD卡的插入拔出。当文件系统加载成功后通知特定应用程序，启动自动播放功能。在U盘或其他外部存储设备移除时，也需要立即通知相应的程序，停止访问这些设备，如播放其中的音视频文件，以免程序出错。

      我们可以使用WinCE设备管理器提供的Device Interface Notification来实现这个功能，参考代码如下。

DWORD WINAPI ThreadFun(LPVOID lpParameter)
 {
     HANDLE ph[MAXIMUM_WAIT_OBJECTS];
     HANDLE phMsgQueue[MAXIMUM_WAIT_OBJECTS-1];
     HANDLE phDevNotif[MAXIMUM_WAIT_OBJECTS-1];
     MSGQUEUEOPTIONS msgopts;
     GUID guid[] = {BLOCK_DRIVER_GUID, FSD_MOUNT_GUID};
     DWORD dwCount;
     BYTE pDevBuf[sizeof(DEVDETAIL) + MAX_DEVCLASS_NAMELEN * sizeof(TCHAR)] = {0};
     DEVDETAIL *pd = (DEVDETAIL*)pDevBuf;

     ghExitThread = CreateEvent(NULL, FALSE, FALSE, NULL);

     ph[0] = ghExitThread;
     dwCount = sizeof(guid)/sizeof(GUID);
     for (DWORD i = 0; i < dwCount; i++)
     {
         memset(&msgopts, 0, sizeof(msgopts));
         msgopts.dwFlags = 0;
         msgopts.dwSize = sizeof(msgopts);
         msgopts.dwMaxMessages = 0; 
         msgopts.cbMaxMessage = sizeof(pDevBuf);
         msgopts.bReadAccess = TRUE;

         phMsgQueue[i] = CreateMsgQueue(NULL, &msgopts);
         phDevNotif[i] = RequestDeviceNotifications(guid+i, phMsgQueue[i], TRUE);
         
         ph[i+1] = phMsgQueue[i];
     }

     while (1)
     {
         DWORD dwSize;
         DWORD dwFlags;
         DWORD dwWait;
         DWORD dwQueue;
     
         dwWait = WaitForMultipleObjects(dwCount + 1, ph, FALSE, INFINITE);
         if ((dwWait <= WAIT_OBJECT_0) || (dwWait >= (WAIT_OBJECT_0 + dwCount + 1))) 
         {
             break;
         }

         dwQueue = (dwWait - WAIT_OBJECT_0) - 1;
         
         while(ReadMsgQueue(phMsgQueue[dwQueue], pd, sizeof(pDevBuf), &dwSize, 1, &dwFlags)) 
         {
             if (GUID_ISEQUAL(pd->guidDevClass, BLOCK_DRIVER_GUID))
             {
                 printf("\r\nDEV:%S %s", pd->szName, pd->fAttached ? "Add!" : "Removed!");
                 if (pd->fAttached)
                 {
                     Sleep(10);
                     printf("\r\nOpenStore!");
                     HANDLE h = OpenStore(pd->szName);
                     STOREINFO si;
                     memset(&si, 0 , sizeof(si));
                     si.cbSize = sizeof(si);
                     printf("\r\nGetStoreInfo!");
                     GetStoreInfo(h, &si);
                     printf("\r\n%S %x", si.szStoreName, si.dwDeviceType);
                     CloseHandle(h);
                 }
             }
             else if(GUID_ISEQUAL(pd->guidDevClass, FSD_MOUNT_GUID))
             {
                 printf("\r\nFSD:%S %s", pd->szName, pd->fAttached ? "Add!" : "Removed!");
             }
             Sleep(1);
         }        
     }
     
     for (DWORD i = 0; i < dwCount; i++) 
     {
         StopDeviceNotifications(phDevNotif[i]);
         CloseMsgQueue(phMsgQueue[i]);
     }    
     CloseHandle(ghExitThread);

     return 0;
 }