C++ ExportAsFixedFormat to save as PDF - c++

Question

I'm using VS2010 C++ and Office 2010 to create reports based on Excel templates. C++ can successfully open, insert values & save the xlsx as something else but I'd like it to also save it as PDF. I'm struggling with the _variant_t parameters of the ExportAsFixedFormat() function despite seeing examples in VB, C# and PowerShell. Can anybody provide example code?
The shell of my functionality:
Excel::_ApplicationPtr pXL;
if (FAILED(pXL.CreateInstance("Excel.Application")))
{
return FALSE;
}
pXL->Workbooks->Open("c:\\tempRep.xlsx");
pXL->PutVisible(0, FALSE);
// Get the active worksheet
Excel::_WorksheetPtr pWksheet = pXL->ActiveSheet;
//... use the spreadsheet
// Save the worksheet
pWksheet->SaveAs("c:\\newRep.xlsx");
pWksheet->ExportAsFixedFormat(??const _variant_t &Filename, ....??)
Thanks, Steve

Answer 1

Try using the SetString method:
_variant_t Filename;
Filename.SetString("c:\\temp\\myfile.txt");
pWksheet->ExportAsFixedFormat(Filename, ....)

Answer 2

From Microsoft 's document, it is 0 or 1 and works for me.
https://msdn.microsoft.com/en-us/library/bb241296(v=office.12).aspx
VARIANT vtMissing; // VARIANT defining a missing/optional parameter.
vtMissing.vt = VT_ERROR;
vtMissing.scode = DISP_E_PARAMNOTFOUND;
book.ExportAsFixedFormat(0, COleVariant(TEXT("myExportPDF.pdf")), vtMissing,
vtMissing, vtMissing, vtMissing, vtMissing, vtMissing, vtMissing);