I'm not sure what exactly you mean.
If you are talking of "object library" as in COM (or similar) then yes of course this is possible. You only need to do the proper raindance for Windows.
I've never done this, but I see no reason why you should be unable to do so with Code::Blocks - there isn't really anything special the IDE has to do, it's just an API you have to use properly (look at MSDN how to do it).
If you are talking of "a way to make a class into a library" and "object library" as in "can I put a class into a library and link against that one?" then yes, this sure is possible too, and very easy.
Again, this does not demand anything particularly special from the IDE. You just make a target for your library, and one for your program that uses it, and that's it (or, you can make two separate projects).
There are generally two pitfalls to watch for when talking of libraries and objects.
The first one is that "objects" usually means "C++" and you have to watch out not to mix C and C++ programs and libraries, this will end miserably. In that case you'll have to make sure the same calling conventions are used everywhere, for example using extern "C" and wrapper functions.
The second one is you cannot mix programs and libraries made with different C++ compilers (even different major versions of the same compiler, or different platforms, such as Intel32 and AMD64), as they have different calling conventions, as well. There is no workaround for this.
A simple example of how to create a library containing a class is attached. The main program creates an object and calls a member function. The object lives in a dynamic library and prints a line of text.
At least with gcc, this works without any additional magic incantations (should work on every other decent compiler too, but I haven't tested).
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