A C++ DLL for Excel that uses Arrays and Ranges.an easy way of implementing a user defined function (UDF) in a C++ dynamic link library the function takes an array as an argument and returns a modified array to Excel. The argument and the returned array can be any or both a Range object or VBA array (a SAFEARRAY).-A C++ DLL for Excel that uses Arrays and Ranges.an easy way of implementing a user defined function (UDF) in a C++ dynamic link library　the function takes an array as an argument and returns a modified array to Excel. The argument and the returned array can be any or both a Range object or VBA array (a SAFEARRAY).