From: Chris Hecker <checker@d6.com>
To: caml-list@inria.fr
Subject: [Caml-list] register_global_root, malloc, etc.
Date: Thu, 26 Jul 2001 01:48:24 -0700 [thread overview]
Message-ID: <4.3.2.7.2.20010726013540.027fa990@shell16.ba.best.com> (raw)
Say I've got the following C struct:
struct foo
{
int something;
value callback;
};
If I'm writing a module in C and want to have an abstract type that corresponds to that struct (allocated with new/malloc/etc. from C), is the following code correct?
CAMLlocal1(result);
foo *p = new foo;
p->callback = Val_unit;
register_global_root(&(p->callback));
result = alloc_small(1,Abstract_tag);
Field(result,0) = (value)p;
CAMLreturn(result);
Then, later, I can just assign another closure passed to a C function (and CAMLparam'ed) to p->callback without worrying about it, like this:
value set_callback( value fooval, value callback )
{
CAMLparam2(fooval,callback);
foo *p = (foo *)Field(fooval,0);
p->callback = callback;
CAMLreturn(Val_unit);
}
Is that correct? Should I use Custom_tag and register all the finalization functions and whatnot for my abstract type, or is Abstract_tag good enough assuming I've got a free_foo function that users of the module are supposed to call to deallocate the abstract type? free_foo should call remove_global_root before deleting the memory, right? But I don't need to do anything to explicitly delete the callback or the Abstract_tag block that was passed in since the GC will handle it?
Thanks,
Chris
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next reply other threads:[~2001-07-26 8:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-26 8:48 Chris Hecker [this message]
2001-08-14 8:25 ` Xavier Leroy
2001-08-15 2:26 ` Alexander V. Voinov
2001-08-16 0:59 ` Chris Hecker
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