Need some help with CString and LPCSTR

Hallo Kevin,
thank you for your answer.
I changed my code to this:

void CZahlen_SortierenDlg::OnBnClickedButton1()
{
       CString D="\\\\\\\\DSERVER\\\\Brother HL-7050 series";
       LPCSTR drucker=(LPCSTR)D;

      HANDLE hDevMode;
      HANDLE hDevNames;
 
 
        if (GetPrinterDevice((LPSTR)drucker, &hDevNames, &hDevMode))
     {
          AfxGetApp()->SelectPrinter(hDevNames, hDevMode);


I will get no error.
But in GetPrinterDevice the printer will not be recognized.


bool CZahlen_SortierenDlg::GetPrinterDevice(LPTSTR pszPrinterName, HGLOBAL* phDevNames, HGLOBAL* phDevMode)
{
      // if NULL is passed, then assume we are setting app object's
    // devmode and devnames
    if (phDevMode == NULL || phDevNames == NULL)
      {
            MessageBox("EPSON LQ-680Pro Port 2 Wiegekarte-1error");
        return FALSE;
      }


    // Open printer
    HANDLE hPrinter;
    if (OpenPrinter(pszPrinterName, &hPrinter, NULL) == FALSE)
      {
            MessageBox("Can not find printer");                will get this message
        return FALSE;
      }

When I look at the string with a break point, it looks the same as in writing "\\\\DSERVER\\Brother HL-7050 series"

Hallo Kent,
if I do not use this: CString D="\\\\\\\\DSERVER\\\\Brother HL-7050 series";
the string at my hardcopy above looks not the same
Best regards,
Thomas

Hallo Kent,
I am sorry you were right....I looked with a breakpoint on

 // Open printer
    HANDLE hPrinter;
    if (OpenPrinter(pszPrinterName, &hPrinter, NULL) == FALSE) to find out how the printer name is with my correct code _T(".....")
      {
            MessageBox("Can not find printer");                will get this message
        return FALSE;
      }

and there were to many \\  even if the break point shows \\\\DSERVER\\Brother HL -7050 series" (see above)
the name of the pszPrinterName was
\\DSERVER\Brother HL -7050 series"


so I reduced the \\ and it works.
Thank you.
Best regards,
Thomas

Thank you for your great help.
Best regards,
Thomas

check the prototype of the GetPrinterDevice function. if the first argument is of type LPCTSTR it means, that the the type is either LPCSTR (or const char *) if using 'multi-byte character set in the project general properties. if using 'UNICODE' character set the LPCTSTR evaluates to LPCWSTR (or const wchar_t *).

you can't cast between LPCSTR and LPCWSTR because char is 8-bit and wchar_t is 16-bit.

generally i wouldn't use the t-types as you always have to be aware of their real types.

so, if you don't have to handle international strings where the ANSI character set is not sufficient, i strongly would advice to using multi-byte character set. then always use the types without 'T' because the compiler would warn you if wide strings came into play. use std::string instead of CString then, because std::string can be used additional to std::wstring while CString is either char or wchar_t and cannot be switched,

if you need windows unicode strings, use consequently wide strings and wchar_t type instead of char. std::wstring is better than CString because the compiler warns if there is a mismatch.

1. Multibyte Character set

void CZahlen_SortierenDlg::OnBnClickedButton1()
{
     HANDLE hDevMode;
     HANDLE hDevNames;

     std::string printer ="\\\\DSERVER\\Brother HL-7050 series";

     if (GetPrinterDevice(printer.c_str()), &hDevNames, &hDevMode)
     {
             ....
      

Select allOpen in new window

2. MS 'UNICODE' character set


1. Multibyte Character set

void CZahlen_SortierenDlg::OnBnClickedButton1()
{
     HANDLE hDevMode;
     HANDLE hDevNames;

     std::wstring printer = L"\\\\DSERVER\\Brother HL-7050 series";

     if (GetPrinterDevice(printer.c_str()), &hDevNames, &hDevMode)
     {
             ....
      

Select allOpen in new window

note, if using WINAPI you often will find functions which have either an 'A' or a 'W' suffix. MS is using typedef's to use either the A(NSI) variant of the function or the 'W'IDE one. if you need both, you always should use the names with suffix. if you only need 'A' or 'W' use consequently names without suffix.

Sara

Thank you Sara for your help.
Best regards,
Thomas