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To: caml-list@inria.fr
Subject: [Caml-list] Questions about the C interface
From: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>
Date: 13 Feb 2003 07:39:52 +0100
Message-ID: <878ywkbs5j.fsf@student.uni-tuebingen.de>
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Hi,

I would like to use C functions to manipulate small binary objects and
Ocaml to manage these objects in data structures. So far, I used
alloc_small(WORDS, Abstract_tag) to allocate them. However, that means
I cannot put them into a Hashtbl, and I cannot compare them. Do I need
"custom blocks" to achieve that? I don't really need any fancy
comparison or hash function, plain memcmp and hash would do. So I
would like to save the overhead of one pointer per object and the more
costly calling.

Also, I'm wondering when exactly I need CAMLparam/local. I would think
that if I don't allocate anything in the C function, I don't need to
protect locals. The manual doesn't mention that, though. Also, I would
think that values that are really ints don't need protection...

Finally, I wonder why the first parameter to alloc_custom (the ops
block) is not a const pointer?

-- 
	Falk
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