Re: [Caml-list] ocamlc linking loads dlls?

[Gerd Stolpmann <info@gerd-stolpmann.de>]

Am 2002.11.15 01:55 schrieb(en) Jacques Garrigue:
> From: Chris Hecker <checker@d6.com>
> 
> > >That point can be resolved by calling LoadLibraryEx with the
> > >DONT_RESOLVE_DLL_REFERENCE flag.
> > >According to MS docs, this prevent the call of DllMain.
> > 
> > That's better, but it still requires the dll to be available.
> 
> I don't see your point.
> All the dlls you mention in ocaml link are supposed to be stub dlls.
> As you write them for your caml program, they are going to be
> available. If more dlls are needed, they are required by dependencies
> in those dlls, and this is what the above flag is supposed to disable.
> This looks fine.
> 
> However, it might still be simpler to a compiler flag to disable all
> dll checking when linking. That's trivial. But if you don't know what
> you do, you're going to have runtime errors later, so this is not a
> reasonable default.

Some time ago, I ran into problems with dll checking. I tried to
embed the ocaml interpreter into another environment by loading
ocamlrun as dll. Unfortunately, I got a loop:

other_environment
  loads: ocamlrun.so
     loads: other_environment_stubs.so
            (to access functions of other_environment)
         uses symbols of other_environment

>From the dll side, there is absolutely no problem, you have only to
ensure that other_environment exports all its symbols to 
subsequently loaded dlls. However, it is not possible to create
an ocaml bytecode executable for this special construction,
because ocamlc cannot load other_environment_stubs.so which
depends on symbols that are only dynamically available. I solved
that by playing with LD_PRELOAD, but this is really not nice.

A switch that turns dll checking off would really have helped me.
I know that embedding ocamlrun as shown is not officially supported,
but it is absolutely cool to dynamically load the whole interpreter
into any program.

Gerd
------------------------------------------------------------
Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany 
gerd@gerd-stolpmann.de          http://www.gerd-stolpmann.de
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