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Date: Sun, 5 Jun 2011 12:18:07 +0200
From: Guillaume Yziquel <guillaume.yziquel@citycable.ch>
To: caml-list@yquem.inria.fr
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Subject: [Caml-list] findlib and ocamlopt -output-obj

Hi.

I'm currently writing mixed code in OCaml and Mercury.

This means that I need to initialise Mercury by a call to mercury_init()
following guidelines in

http://www.mercury.csse.unimelb.edu.au/information/doc-release/mercury_user_guide/Stand_002dalone-Interfaces.html#Stand_002dalone-Interfaces

This requires to pass an address (i.e. stackbottom) to mercury_init
that informs Boehm's GC of where it should begin tracing. So
essentially, you need to start OCaml from a C main() and have
stackbottom allocated on main()'s stack frame. Something like:

	yziquel@seldon:~$ cat mercury_init.c 
	value mercury_stackbottom;

	int main (int argc, char ** argv) {

		void * stackbottom;	// Word aligned
		mercury_stackbottom = (value) &stackbottom;

		caml_startup (argv);

		return 0;
	}

mercury_init() then gets called as a C stub from OCaml code, and the C
stub uses the mercury_stackbottom global.

However, to generate an executable out of all that, I need to link in
quite a lot of findlib dependencies. I'm currently doing it explicitely
by calling ocamlopt with all the dependencies manually, but I failed to
manage to use ocamlfind together with the -output-obj command line
option to pull in the dependencies. Anyone knows how to do that?

-- 
     Guillaume Yziquel