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Re: gcc34 and older libraries


>Is it possible?

Short answer: no, it is not possible to use GCC 2.95 C++ libraries with GCC 3.x compiled C++ code.

Long answer: yes, it is possible. But you don't want to do it.

To make it possible requires making a C thunk layer which interfaces to the GCC 2.95 C++ libraries (compiled with GCC 2.95, obviously), then link against the C thunk libraries with GCC 3.x.

If you want the C thunk libraries to behave "C++ ish", you'll need to write a C++ wrapper over the C thunk library, which your wrappers and your C++ code compiled with GCC 3.x uses.

You'll have to handle each exception with kid's gloves, since exceptions cannot propagate over a C barrier (they couldn't propagate anyway, since the GCC 2.95 C++ ABIs are different from the GCC 3.x C++ ABI). You'll need to catch them in your GCC 2.95 C thunk layer, serialize them to your C++ wrapper which then can reconstitute them in your GCC 3.x world.

Note: GCC 3.x C++ ABIs have some differences as well. I think 3.0.x is one ABI, 3.1.x is another, 3.2.x-3.4.x is yet another. If I remember correctly. It's documented somewhere.

Also, RTTI and dynamic casting will have issues as well. You'll need to treat them with kids gloves as well.

And if you do things JUST right, you'll also get to shoot yourself in the foot by having different heap managers involved. *laugh*

You may say, "Yikes, that's a lot of work! No one would do that!"

In my job, I do it all the time. And it is a lot of work. I wouldn't wish it on anyone.


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