C / C++ / MFC

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

// simply copied from MSDN
BOOL CMyApp::SetPrinterDevice(LPTSTR pszDeviceName)
{
   // Open printer and obtain PRINTER_INFO_2 structure.
   HANDLE hPrinter;
   if (OpenPrinter(pszDeviceName, &hPrinter, NULL) == FALSE)
       return FALSE;
   DWORD dwBytesReturned, dwBytesNeeded;
   GetPrinter(hPrinter, 2, NULL, 0, &dwBytesNeeded);
   PRINTER_INFO_2* p2 = (PRINTER_INFO_2*)GlobalAlloc(GPTR,
       dwBytesNeeded);
   if (GetPrinter(hPrinter, 2, (LPBYTE)p2, dwBytesNeeded,
       &dwBytesReturned) == 0)
   {
	   GlobalFree(p2);
	   ClosePrinter(hPrinter);
	   return FALSE;
   }
   ClosePrinter(hPrinter);

// Allocate a global handle for DEVMODE and copy DEVMODE data.
   HGLOBAL  hDevMode = GlobalAlloc(GHND, sizeof(*p2->pDevMode) +
      p2->pDevMode->dmDriverExtra);
   DEVMODE* pDevMode = (DEVMODE*)GlobalLock(hDevMode);
   memcpy(pDevMode, p2->pDevMode, sizeof(*p2->pDevMode) +
      p2->pDevMode->dmDriverExtra);
   GlobalUnlock(hDevMode);

// Compute size of DEVNAMES structure you'll need.
   DWORD drvNameLen = _tcslen(p2->pDriverName);  // driver name
   DWORD ptrNameLen = _tcslen(p2->pPrinterName); // printer name
   DWORD porNameLen = _tcslen(p2->pPortName);    // port name
   DWORD devNameSize = sizeof(DEVNAMES) +
       (ptrNameLen + porNameLen + drvNameLen + 3)*sizeof(TCHAR);

   // Allocate a global handle big enough to hold DEVNAMES.
   HGLOBAL   hDevNames = GlobalAlloc(GHND, devNameSize);
   DEVNAMES* pDevNames = (DEVNAMES*)GlobalLock(hDevNames);

   // Copy the DEVNAMES information from PRINTER_INFO_2 structure.
   pDevNames->wDriverOffset = sizeof(DEVNAMES)/sizeof(TCHAR);
   memcpy((LPTSTR)pDevNames + pDevNames->wDriverOffset,
       p2->pDriverName, drvNameLen*sizeof(TCHAR));

   pDevNames->wDeviceOffset = (WORD)(pDevNames->wDriverOffset + drvNameLen + 1);
   memcpy((LPTSTR)pDevNames + pDevNames->wDeviceOffset,
       p2->pPrinterName, ptrNameLen*sizeof(TCHAR));

   pDevNames->wOutputOffset = (WORD)(pDevNames->wDeviceOffset + ptrNameLen + 1);
   memcpy((LPTSTR)pDevNames + pDevNames->wOutputOffset,
       p2->pPortName, porNameLen*sizeof(TCHAR));

   pDevNames->wDefault = 0;

   GlobalUnlock(hDevNames);
   GlobalFree(p2);   // free PRINTER_INFO_2

   m_hDevMode = hDevMode;
   m_hDevNames = hDevNames;
   return TRUE;
}