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[Caml-list] Reference to undefined global using Dynlink module.
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Date: 2002-11-28 (23:40)
From: Alessandro Baretta <alex@b...>
Subject: Re: [Caml-list] Reference to undefined global using Dynlink module.

Dmitri Boulytchev wrote:
>         Hello everybody,
>         I didn't get as answer browsing the archive so I decided to ask.
>         How to avoid "Reference to undefined global ***" error during
>         loading *.cmo via Dynlink  module?

I had the same problem so I am competent on the subject. I 
bet your code looks like the following:
open Dynlink

let foo = <whatever>

let _ = loadfile "b.cmo"

... ...

Thi is your problem. When you try to access, module A 
has not completed initialization, so it's values appear to 
be yet undefined to all other modules.

What you have to do is create a file which is 
initialized last--that is, linked last--where you call the 
Dynlink library to load Here's how to do it:
let foo = <whatever>
... ....
open Dynlink

let _ = loadfile "b.cmo"

all : dynlinked_prog b.cmo

b.cmo :
	ocamlc -c

	ocamlc -o $@
# notice the order in which the files are compiled


When you run make you get an executable and a CMO. When you 
run the executable, all the modules that are statically 
linked into it are initialized in the order they were 
specified in. So first A is initialized (and is 
defined); then, main is initialized (and Dynlink.loadfile is 
called). Thus, when loadfile is called, no dynamic linking 
error occurs.


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