How to use standard COM method to link a Qt GCC C++ .exe and a project in MVS C++?

[ChrisW67]

Here are a few options:

• You build Qt and your application using MSVC++ and the C++ ABI problem goes away.
• If you can get the source and build it with MingW, or if the DLL author could build you a version using MingW, then C++ ABI problem goes away. You may have to do some work to adjust MSVC specific things in the code, and things missing in the MingW headers, to make it build.
• If the DLL author can produce a C only interface to the functionality of catDataPreparator then the problem goes away (whether she uses MSVC or not).
• If the DLL author can produce a COM wrapper around catDataPreparator then the problem goes away (whether she uses MSVC or not). In this case you use ActiveQt to access the functionality.

Which of these options is best really depends on what catDataPreparator does and how accommodating the DLL provider is.