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From: Wojciech Meyer <wojciech.meyer@googlemail.com>
To: Joel Reymont <joelr1@gmail.com>
Cc: caml-list@inria.fr
References: <CAOQwdX2tiD3U0urR_x61RLUVwAbiFqRV9dbEEabM2nKWFtA0gw@mail.gmail.com>
Date: Fri, 04 May 2012 23:28:32 +0100
In-Reply-To: <CAOQwdX2tiD3U0urR_x61RLUVwAbiFqRV9dbEEabM2nKWFtA0gw@mail.gmail.com>
	(Joel Reymont's message of "Fri, 4 May 2012 21:56:51 +0100")
Message-ID: <wf4nrv7f8v.fsf@gmail.com>
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Subject: Re: [Caml-list] debugging c wrappers


Hello Joel,

Joel Reymont <joelr1@gmail.com> writes:

> How do I look inside the values in C functions called from OCaml when
> running in gdb?
>
> I swear there's a way but I don't remember it now.
>
> For example, I want to check if a particular value is a variant
> constructor and whether its first argument is a closure.
>
> Help!

In general case this is not currently possible, but I think there is
some work going on by OCamlPro for better gdb integration [1], if you
are talking about showing precise types - as it needs some extra debug
information.

To see if it's a variant constructor, array, string or closure etc. you
can look at the tag however.

There is a Python script by Ygrek [2] that probably to some extent does what
you want.

- Wojciech

[1] http://caml.inria.fr/mantis/view.php?id=5487
[2] http://ygrek.org.ua/p/code/mlvalues.py.html