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To: Ohad Rodeh <orodeh@cs.huji.ac.il>
Cc: caml-list@inria.fr
Subject: Re: Calling C++ from Caml
References: <Pine.LNX.4.20_heb2.08.0004161630460.6495-100000@zigzag.cs.huji.ac.il>
From: John Prevost <prevost@maya.com>
Date: 17 Apr 2000 15:25:36 -0400
In-Reply-To: Ohad Rodeh's message of "Sun, 16 Apr 2000 16:40:44 +0300 (IDT)"
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>>>>> "or" == Ohad Rodeh <orodeh@cs.huji.ac.il> writes:

    or> Hello, I'm trying to use C++ code from within Caml. Currently,
    or> the compiler cannot find the requested functions in the
    or> compiled C++ code.

        {...}

    or>   If I use the gcc compiler with C code, instead of C++, this
    or> sequence works fine. How can I fix this problem?

C++ compilers need to do "name-mangling" in order to support
overloading functions.  This adds information about the types of the
arguments to the function's name, and makes it hard for O'Caml to
find.

I suspect that using the following prototype would work for you:

extern "C" {
  value dhml_Try(value dummy);
}

the `extern "C"' part requests that the following be done with C
calling conventions.  I'm not up on my C++, so this may be
insufficient when you're defining the function in the current
file--you may need to use the extern declaration around the function's
definition.

John.