Processing a Request to Remove a Device

#include <windows.h>#include <dbt.h>#include <strsafe.h> LPCTSTR FileName; // path to the file or device of interest HANDLE hFile; // handle to the file or device PDEV_BROADCAST_HDR pDBHdr; PDEV_BROADCAST_HANDLE pDBHandle; char szMsg[80]; case WM_DEVICECHANGE: switch (wParam){ case DBT_DEVICEQUERYREMOVE: pDBHdr = (PDEV_BROADCAST_HDR) lParam; switch (pDBHdr->dbch_devicetype){case DBT_DEVTYP_HANDLE:// A request has been made to remove the device;// close any open handles to the file or devicepDBHandle = (PDEV_BROADCAST_HANDLE) pDBHdr;if (hFile != INVALID_HANDLE_VALUE) {CloseHandle(hFile);hFile = INVALID_HANDLE_VALUE;}}return TRUE;case DBT_DEVICEQUERYREMOVEFAILED:pDBHdr = (PDEV_BROADCAST_HDR) lParam;switch (pDBHdr->dbch_devicetype){case DBT_DEVTYP_HANDLE:// Removal of the device has failed;// reopen a handle to the file or devicepDBHandle = (PDEV_BROADCAST_HANDLE) pDBHdr;hFile = CreateFile(FileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);if (hFile == INVALID_HANDLE_VALUE) {StringCchPrintf(szMsg, 80, "CreateFile failed: %lx./n", GetLastError());MessageBox(hwnd, szMsg, "CreateFile", MB_OK);}}return TRUE;case DBT_DEVICEREMOVEPENDING:pDBHdr = (PDEV_BROADCAST_HDR) lParam;switch (pDBHdr->dbch_devicetype){case DBT_DEVTYP_HANDLE:// All queries for removal of the device were // successful; device removal is pending;}return TRUE;case DBT_DEVICEREMOVECOMPLETE:pDBHdr = (PDEV_BROADCAST_HDR) lParam;switch (pDBHdr->dbch_devicetype){case DBT_DEVTYP_HANDLE:pDBHandle = (PDEV_BROADCAST_HANDLE) pDBHdr;// The device has been removed from the system;// unregister its notification handleUnregisterDeviceNotification(pDBHandle->dbch_hdevnotify);}return TRUE;default:return TRUE;}