Detecting Media Insertion or Removal

#include <windows.h> #include <dbt.h> #include <strsafe.h> #pragma comment(lib, "user32.lib") void Main_OnDeviceChange (HWND hwnd, WPARAM wParam, LPARAM lParam); char FirstDriveFromMask (ULONG unitmask); //prototype /*------------------------------------------------------------------ Main_OnDeviceChange (hwnd, wParam, lParam) Description Handles WM_DEVICECHANGE messages sent to the application's top-level window. --------------------------------------------------------------------*/ void Main_OnDeviceChange (HWND hwnd, WPARAM wParam, LPARAM lParam) { PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)lParam; char szMsg[80]; switch(wParam) { case DBT_DEVICEARRIVAL: // Check whether a CD or DVD was inserted into a drive. if (lpdb -> dbch_devicetype == DBT_DEVTYP_VOLUME) { PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb; if (lpdbv -> dbcv_flags & DBTF_MEDIA) { StringCchPrintf (szMsg, 80, "Drive %c: Media has arrived./n", FirstDriveFromMask(lpdbv ->dbcv_unitmask)); MessageBox (hwnd, szMsg, "WM_DEVICECHANGE", MB_OK); } } break; case DBT_DEVICEREMOVECOMPLETE: // Check whether a CD or DVD was removed from a drive. if (lpdb -> dbch_devicetype == DBT_DEVTYP_VOLUME) { PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb; if (lpdbv -> dbcv_flags & DBTF_MEDIA) { StringCchPrintf (szMsg, 80, "Drive %c: Media was removed./n", FirstDriveFromMask(lpdbv ->dbcv_unitmask)); MessageBox (hwnd, szMsg, "WM_DEVICECHANGE", MB_OK); } } break; default: /* Process other WM_DEVICECHANGE notifications for other devices or reasons. */ ; } } /*------------------------------------------------------------------ FirstDriveFromMask (unitmask) Description Finds the first valid drive letter from a mask of drive letters. The mask must be in the format bit 0 = A, bit 1 = B, bit 2 = C, and so on. A valid drive letter is defined when the corresponding bit is set to 1. Returns the first drive letter that was found. --------------------------------------------------------------------*/ char FirstDriveFromMask (ULONG unitmask) { char i; for (i = 0; i < 26; ++i) { if (unitmask & 0x1) break; unitmask = unitmask >> 1; } return (i + 'A'); }