xloper12 variable xltype = str using wide characters

Question

I am trying to register some functions and have success up until the length of my string exceeds 255. I have written the below function to cycle through the list of parameters and convert the L"xxparametersxx". For any string <255 characters it works fine but when I get to the 256 character string it does not enter the corresponding code for the # of characters in the first entry. Would anyone have any ideas here please?

Joe

Function Code:

XLOPER12 CreateXLOPER12FromWStr(LPCWSTR cInput)

    XLOPER12 lpx;

    size_t len;

    len = wcslen(cInput);   wchar_t* lps = (wchar_t *)malloc((len + 2) * sizeof(wchar_t));

    lps[0] = (wchar_t)(len+2);

    wmemcpy_s(lps + 1, len, cInput, len);   lpx.xltype = xltypeStr;     lpx.val.str = lps;

    return lpx;

Answer 1

Your function above appears valid (except missing braces!) and I can run it, although I'm not sure why you put len+2 into lps[0]: just the string length is sufficient. You may be hitting other limitations downstream, if you are using xlfRegister:

• The total length of comma-separated parameter names must be < 256 chars
• Help strings must be < 256 chars
• Function name must be < 256 chars

This is despite the XLOPER12 type allowing for considerably longer strings.

I don't recommend that anyone else use the C API directly: rather use my library xlOil which hides implementation details like the above and adds COM, GUI & RTD support. Or use Keith's xlladdins.