How to create a new port and assign it to a printer

Question

We have a virtual printer (provided by a 3rd party) that is getting assigned to an invalid local printer port. The printer is always local (we aren\'t dealing with a remote

Answer 1

I guess your code merely worked by chance. According to https://docs.microsoft.com/en-us/windows-hardware/drivers/print/tcpmon-xcv-commands (and to my own experience) the real solution is:

PORT_DATA_1 pdPortData;  
wcscpy_s(pdPortData.sztPortName, MAX_PORTNAME_LEN, lpPortName);  
[...]
if (!XcvData(hXcv, L"AddPort", (BYTE*) &pdPortData, sizeof(PORT_DATA_1), NULL, 0, &dwNeeded, &dwStatus))
[...]

By chance sztPortName is the first element in PORT_DATA_1 structure. Maybe that's why your code did not fail, although it is wrong.

Answer 2

Wow, looks like that one stumped everyone... After much digging, here's how to do it:

DWORD CreatePort(LPWSTR portName)
{
      HANDLE hPrinter;
      PRINTER_DEFAULTS PrinterDefaults;
      memset(&PrinterDefaults, 0, sizeof(PrinterDefaults));

      PrinterDefaults.pDatatype = NULL;
      PrinterDefaults.pDevMode = NULL;
      PrinterDefaults.DesiredAccess = SERVER_ACCESS_ADMINISTER;

      DWORD needed;
      DWORD rslt;


      if (!OpenPrinter(",XcvMonitor Local Port", &hPrinter, &PrinterDefaults))
          return -1;

      DWORD xcvresult= 0;
      if (!XcvData(hPrinter, L"AddPort", (BYTE *)portName, (lstrlenW(portName) + 1)*2, NULL, 0, &needed, &xcvresult))
            rslt= GetLastError();

      if (!ClosePrinter(hPrinter))
          rslt= GetLastError();

      return rslt;
}

Setting the port on a given printer is relatively straight forward - OpenPrinter(), GetPrinter() with PRINTER_INFO_2, SetPrinter(), ClosePrinter()

Cheerio.