I have an old Excel addin consisting of an XLL and DLLs written in C++ and C which were developed for Excel 2003, and a XLA file which contains an Excel 4.0 worksheet interface to the C++ functions. I do not have the source code.
The addins worked perfectly in Excel 2010 but in 2013 the XLA file would not load the addins. I could work around the problem by loading the XLL directly. Now I have moved to 2016 64-bit and the addins do not work at all. The XLL does not load.
Can anyone write a C++ wrapper for the functions that would work in 64 bit Excel – and provide the source code of the wrapper so that I can recompile for future versions?
I would want you to demonstrate that your approach works on one function for a nominal cost then do all the functions. There are around 100 functions with parameters of many data types. Ideally the creation of the wrappers would be automated to avoid risk that data types were accidently transcribed incorrectly. If, however, the process is manual I could restrict just to the 10-20 essential functions.
There are no call backs from the XLL/DLLs into Excel, all the functions simply take arguments as inputs and return results as function return values – although there are various data type, including arrays, among the input and return variables.
Hello. If your DLL is 32 bit, in this case 64bit Excel cannot load it, meantime I have installed 32bit Excel 2013, I think it's better to try to load your XLL in this environment.