[Mingw-users] Re: Generic DLL questions

[Stefan B. <sb...@sb...>]

Tor Lillqvist wrote:
> > 2) On GNU/Linux, I have one project where one shared object refers
> > back to symbols of the main application. [...] Now, when trying to
> > build the same on Windows (using gcc -shared as well), the DLL
> > doesn't even build but throws errors of "undefined references". I
> > want those to get resolved when linking against the main
> > application. Is such a set-up not possible on Windows?

> It is possible, but it is not as flexible as on ELF-based systems like
> Linux. Firstly, you must mark the function in the main .exe that you
> want to access from a DLL for export using
> __declspec(dllexport). Then, there are two possibilities how to
> actually access the functions from the DLL:

> 1) you can create an import library for the foo.exe using a foo.def
> file like this:

[snip]

>     dlltool --input-def foo.def --output-lib libfoo.a --dllname
>     foo.exe

> Then link the DLL with libfoo.a.

Ok, I see. However, this doesn't work if the foo.exe itself depends on
the DLL. So, circular dependencies are impossible, correct?

> 2) Look up the symbol at runtime. Read up on GetProcAddress() and
> GetModuleHandle().

And how would I link the DLL itself using this second approach?

-- 
Stefan Bellon