USB storage device plug event detection.

main.cpp

#include <Windows.h>
#include <Dbt.h>
#include "resource.h"

INT_PTR CALLBACK DialogProc(HWND hDlg, UINT uMsg, WPARAM wParam,
                            LPARAM lParam) {
  switch (uMsg) {
  case WM_DEVICECHANGE:
    PDEV_BROADCAST_HDR pHdr = (PDEV_BROADCAST_HDR)lParam;
    switch (pHdr->dbch_devicetype) {
    case DBT_DEVTYP_VOLUME: {
      PDEV_BROADCAST_VOLUME pDevVolume = (PDEV_BROADCAST_VOLUME)pHdr;
      for (int i = 0; i < 26; i++) {
        if (pDevVolume->dbcv_unitmask & (1 << i)) {
          char letter = 'A' + i;
          
          if (DBT_DEVICEARRIVAL == wParam) {
            // Plug in. volume drive letter is in var 'letter'
          } else if (DBT_DEVICEREMOVECOMPLETE == wParam) {
            // Plug out. volume drive letter is in var 'letter'
          }
        }
      }
      break;
    }
    }
    break;
  case WM_COMMAND:
    switch (LOWORD(wParam)) {
    case IDCANCEL:
      SendMessage(hDlg, WM_CLOSE, 0, 0);
      return TRUE;
    }
    break;

  case WM_CLOSE:
    if (MessageBox(hDlg, TEXT("Close the program?"), TEXT("Close"),
                   MB_ICONQUESTION | MB_YESNO) == IDYES) {
      DestroyWindow(hDlg);
    }
    return TRUE;

  case WM_DESTROY:
    PostQuitMessage(0);
    return TRUE;
  }

  return FALSE;
}

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE h0, LPSTR lpCmdLine, int nCmdShow) {
  HWND hDlg;
  MSG msg;
  BOOL ret;

  // Need add a resource, add a dialog.
  hDlg =
    CreateDialogParam(hInst, MAKEINTRESOURCE(IDD_DIALOG1), 0, DialogProc, 0);

  ShowWindow(hDlg, SW_HIDE);

  while ((ret = GetMessage(&msg, 0, 0, 0)) != 0) {
    if (ret == -1) return -1;
    if (!IsDialogMessage(hDlg, &msg)) {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
    }
  }

  return 0;
}