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Date: Wed, 17 Aug 2005 16:12:56 +1200
From: Jonathan Roewen <jonathan.roewen@gmail.com>
To: caml-list@yquem.inria.fr
Subject: [Caml-list] Stopping a value from getting GC'd
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Hi,

I have the following in my C code:

struct caml_thread_struct {
=09char * bottom_of_stack;
=09unsigned long last_retaddr;
=09value * gc_regs;
=09char * exception_pointer;
=09struct caml__roots_block * local_roots;
=09int is_running;
=09value closure;
};

typedef struct caml_thread_struct * caml_thread_t;

static value Val_thread(caml_thread_t thread) {
=09CAMLparam0();
=09CAMLlocal1(rv);
=09rv =3D caml_alloc(1, Abstract_tag);
=09Field(rv,0) =3D (value) thread;
=09CAMLreturn(rv);
}

#define Thread_val(rv) ((caml_thread_t)Field((rv),0))

Now my question is, since my Thread.t is abstract, once I pass my
value to my Thread.create, there'll soon be nothing referencing the
closure for the thread that's visible by the GC.

If I'm correct, the GC would then be allowed to reclaim this closure.
So how do I stop the GC from doing that?

Jonathan