This site contains older material on Eiffel. For the main Eiffel page, see

Frequently asked questions about Eiffel

This page addresses some commonly asked questions about Eiffel and the ISE environment.

See also:

I don't quite understand how to use external C functions from Eiffel.

    Read the technical note that explains everything there is to know about using external C functions.

Can I also use C++ classes from Eiffel?

    Yes. See the technology paper that says it all about the C++ interface and the Legacy++ class wrapper.

What about calling Eiffel from C or C++?

Is there an EMACS mode for Eiffel?

    Yes. Our FTP server has two files addressing this need. XEmacs distribution also contains a mode for Eiffel.

Does Eiffel support multi-threading?

Is there a concurrency mechanism proposed for Eiffel?

Is there any good reason why loop variants can only be integers?

    Yes. This is explained in a short technical note which introduces some of the (simple) mathematical background.

If you have any interesting questions that you think would be useful additions to this page, then please email to