Службы и GDI

  SC_HANDLE hSCManager = OpenSCManager(NULL, NULL, SC_MANAGER_CREATE_SERVICE);
  if(!hSCManager) {
    return false;
  }
  
  GetModuleFileName(NULL, servicePath, MAX_PATH);
  DWORD wver = LOWORD(GetVersion());
  wver = (LOBYTE(wver) << 8) + HIBYTE(wver);
  DWORD stype = SERVICE_WIN32_OWN_PROCESS;
  if (wver < 0x0600) {
    stype |= SERVICE_INTERACTIVE_PROCESS;
  }
  SC_HANDLE hService = CreateService(
     hSCManager,
     serviceName,
     serviceName,
     SERVICE_ALL_ACCESS,
     stype,
     SERVICE_AUTO_START,
     SERVICE_ERROR_NORMAL,
     servicePath,
     NULL, NULL, NULL, NULL, NULL
  );
 
  CloseServiceHandle(hService);
  CloseServiceHandle(hSCManager);

  STARTUPINFO si;
  PROCESS_INFORMATION pi;
  memset(&si, 0, sizeof(si));
  si.cb = sizeof(si);
  memset(&pi, 0, sizeof(pi));
  
  HANDLE proc = GetCurrentProcess();
  HANDLE cur_token, new_token;
  DWORD session = WTSGetActiveConsoleSessionId();
  
  if (!OpenProcessToken(proc, TOKEN_DUPLICATE, &cur_token)) {
    return false;
  }
  if (!DuplicateTokenEx(cur_token, TOKEN_ALL_ACCESS, 0, SecurityImpersonation, TokenPrimary, &new_token)) {
    return false;
  }
  if (!SetTokenInformation(new_token, (TOKEN_INFORMATION_CLASS) TokenSessionId, &session, sizeof(session))) {
    return false;
  }
 
  CreateProcessAsUser(new_token, NULL, "program.exe scr", NULL, NULL, FALSE, NORMAL_PRIORITY_CLASS, NULL, NULL, &si, &pi);
 
  CloseHandle(token);
  CloseHandle(userToken);

  HDC winDC = CreateDC(_T("DISPLAY"), NULL, NULL, NULL);
  HDC bmpDC = CreateCompatibleDC(winDC);
 
  int width = GetDeviceCaps(winDC, HORZRES);
  int height = GetDeviceCaps(winDC, VERTRES);
 
  BITMAPINFOHEADER bmpInfoHeader;
  BITMAPFILEHEADER bmpFileHeader;
 
  bmpFileHeader.bfType = 0x4d42;
  bmpFileHeader.bfSize = 0;
  bmpFileHeader.bfReserved1 = 0;
  bmpFileHeader.bfReserved2 = 0;
  bmpFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
 
  bmpInfoHeader.biSize = sizeof(bmpInfoHeader);
  bmpInfoHeader.biWidth = width;
  bmpInfoHeader.biHeight = height;
  bmpInfoHeader.biPlanes = 1;
  bmpInfoHeader.biBitCount = 24;
  bmpInfoHeader.biCompression = BI_RGB;
  bmpInfoHeader.biSizeImage = width * height * 3;
  bmpInfoHeader.biXPelsPerMeter = 0;
  bmpInfoHeader.biYPelsPerMeter = 0;
  bmpInfoHeader.biClrUsed = 0;
  bmpInfoHeader.biClrImportant = 0;
  
  BITMAPINFO info;
  info.bmiHeader = bmpInfoHeader;
 
  void* memory;
  HBITMAP bitmap;
  bitmap = CreateDIBSection(winDC, &info, DIB_RGB_COLORS, &memory, NULL, 0);
  SelectObject(bmpDC, bitmap);
  if (!BitBlt(bmpDC, 0, 0, width, height, winDC, 0, 0, SRCCOPY | CAPTUREBLT)) {
    return false;
  }
 
  FILE *f = fopen("scrsht.bmp", "wb");
  fwrite(&bmpFileHeader, 1, sizeof(BITMAPFILEHEADER), f);
  fwrite(&bmpInfoHeader, 1, sizeof(BITMAPINFOHEADER), f);
  fwrite(memory, 1, bmpInfoHeader.biSizeImage, f);
  fclose(f);