OpenEuphoria

RE: Wrapping C++ libraries (was RE: Future of Euphoria)

• Posted by Ray Smith <smithr at ix.net.au> Jun 03, 2002
• 431 views

Matthew Lewis wrote:
[snip]
> Right.  It helps to understand what, exactly, something like C++ does 
> with
> classes at the binary level (turns out to be the same thing COM does).  
> Each
> class has a vtbl, or a virtual function table.  Which is to say, its an
> array of pointers in memory.  The pointers are to the functions in the
> class.  An instance of the class will basically be a pointer to the 
> vtbl.
> This pointer is AKA the 'this' pointer.  The this pointer is 
> automatically
> the first param passed to any function in the class.  C++ does this
> automatically--Eu must do this explicitly.  Also, there's no built in 
> way to
> call functions by pointer in Eu (unless there are no params to be 
> passed).
> But I've figured that out, too :).
[snip]

gee, this is pretty interesting and in depth stuff!!!

My plan was to cheat a little and write a DLL in standard C which 
access the C++ objects (like SWIG - but do it manually).
ie. convert the OO to a non OO library with a wrapper ... 
or create a wrapper on a wrapper.
 
Then Euphoria will just call the C routines which will call the C++
routines.  It's most likely more work but possibly easier.

I actaully started a project to automate most of the C and euphoria
code when I did the same thing for Allegro (but never finished it).  It 
couldn't parse header files but I just created data files and it 
created the C DLL and the Euphoria wrapper.

So after all that ... I guess my question should have been 

how do I create C wrapper for a C++ library??

Thanks,

Ray Smith
http://rays-web.com