Getting/Setting the Default Printer from Windows

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.0 and 3.1

SUMMARY

The "device=" entry in the [windows] section of WIN.INI refers to the default printer. The way to change it is to call WriteProfileString("windows", "device", szNewPrinterSpec), where szNewPrinterSpec is of the form "printer name, printer driver base filename, port connected to printer". For example:

   HP LaserJet IIISi,HPPCL5MS,LPT1:

MORE INFORMATION

The currently installed printers are contained in the WIN.INI [devices] section. It is possible to build a list of the installed printers by calling GetProfileString("devices", NULL, "", szDriverNames, sizeof(szDriverNames)). This will fill the szDriverNames with the names of all printers installed separated by a null byte, with a double null byte at the end of the list.

Choose the new printer from the list provided and call GetProfileString("devices", szDriverRequested, "", szPrinter, sizeof(szPrinter)) with szDriverRequested set to the printer name requested. Once the call returns, the szPrinter will contain the rest of the information needed to create the szNewPrinterSpec. Create a new szPrinterSpec from both szPrinterRequested and szPrinter and make the call.

Once WIN.INI is updated, call SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, 0L) to send the correct notification to all top level windows after WIN.INI gets changed programmatically. Applications that care about WIN.INI listen for this message and reread WIN.INI as needed.

The following code gets and sets the default printer:

   #include <windows.h>
   #include <string.h>

   #define MAXSTRING 255

   int PASCAL WinMain(HINSTANCE hInst, HINSTANCE hPrevInst,
                      LPSTR lpszCmdLine, int CmdShow)
   {
      char szFmtStr  [] = "%s,%s";
      char szDevice  [] = "device";
      char szDevices [] = "devices";
      char szWindows [] = "windows";
      char szDefault [] = "default";
      char szInstPrn [] = "Set this installed printer as default?";
      char szDefPrn  [] = "The default printer";
      char szBuff    [MAXSTRING];
      char szRetBuff [MAXSTRING];
      char szVal     [MAXSTRING];
      int nBytes;
      HLOCAL hLocal;
      PSTR pszBuf, pszKey;

      nBytes = GetProfileString(szWindows, szDevice, szDefault, szRetBuff,
                                sizeof(szRetBuff));

      MessageBox(NULL,szRetBuff, szDefPrn, MB_OK | MB_ICONINFORMATION);

      hLocal = LocalAlloc(LHND, 1024);
      pszBuf = (PSTR) LocalLock(hLocal);

      GetProfileString(szDevices, NULL, szDefault, pszBuf, 1024);

      for (pszKey = pszBuf; *pszKey != '\0'; pszKey += strlen(pszKey) + 1)
      {
         int nID;

         GetProfileString(szDevices, pszKey, szDefault,
                          szVal, sizeof(szVal));
         wsprintf(szBuff, szFmtStr, (LPSTR) pszKey, (LPSTR) szVal);
         nID = MessageBox(NULL, szBuff, szInstPrn, MB_YESNOCANCEL
                         | MB_ICONQUESTION);
         switch(nID)
         {
            case IDNO:
               continue;

            case IDYES:
               WriteProfileString(szWindows, szDevice, szBuff);
               WriteProfileString(NULL, NULL, NULL);
               SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, 0L);

            default:
               break;

         }
         break;
      }
      LocalUnlock(hLocal);
      LocalFree(hLocal);
      return(0);
   }