Returns the name of the sheet (xltypeStr), given an external reference.
Excel4(xlSheetNm, LPXLOPER pxRes, 1, LPXLOPER pxExtref);
pxExtref (xltypeRef)
An external reference to the sheet whose name you want.
This function returns the name of the sheet in the form "[Book1]Sheet1."
The following example returns the name of the sheet from which the function was called.
\SAMPLES\EXAMPLE\EXAMPLE.C
short WINAPI xlSheetNmExample(void)
{
    XLOPER xRes, xSheetName;
    Excel4(xlfCaller, &xRes, 0);
    Excel4(xlSheetNm, &xSheetName, 1, (LPXLOPER)&xRes);
    Excel4(xlcAlert, 0, 1, &xSheetName);
    Excel4(xlFree, 0, 1, &xSheetName);
    return 1;
}
xlSheetId