[SOLVED] Receive a matrix from excel in c++ xll, modifying it and returning it

Receive a matrix from excel in c++ xll, modifying it and returning it

I coded up an xll function receiving a matrix from excel, modifying it a returning it :

__declspec(dllexport) LPXLOPER12 WINAPI ZZZZUpdateArray1(LPXLOPER12 arrayin)
{
    if (arrayin->xltype == xltypeMulti | xlbitDLLFree)
    {
        double ScaleFactor = 2.0;
        int rows = arrayin->val.array.rows;
        int cols = arrayin->val.array.columns;
        static XLOPER12 xlArray;
        xlArray.val.array.lparray = reinterpret_cast<LPXLOPER12>(::new XLOPER12[rows * cols] /*::malloc(rows * cols * sizeof(XLOPER12))*/);
        for (int r = 0; r<rows; r++)
        {
            for (int c = 0; c<cols; c++)
            {
                if ((arrayin->val.array.lparray + ((r* cols) + c))->xltype == xltypeNum)
                {
                    XLOPER12* var = xlArray.val.array.lparray + ((r* cols) + c);
                    var->xltype = xltypeNum;
                    var->val.num = ScaleFactor*(arrayin->val.array.lparray + ((r* cols) + c))->val.num ;
                }
            }
        }
        return static_cast<LPXLOPER12>(&xlArray);
    }
    return arrayin;
}

but it crashes on

if ((arrayin->val.array.lparray + ((r* cols) + c))->xltype == xltypeNum)

If I am for instance taking a 5*5 matrix from excel, at debug I see it having 19 rows and 20 colums, what happened !?

Is it maybe because when I receive the LPXLOPER12 arrayin, it represents an excel range, way more complicated than a 5*5 matrix. How to access the 5*5 matrix it contains, then ?

Solution

Use the Excel code Q to register the input argument.

You need to declare properly the return variable :

// initialize the return variable
xlArray.val.array.rows = rows;
xlArray.val.array.columns = cols;
xlArray.xltype = xltypeMulti | xlbitDLLFree;