From: Kent Sibilev <ksibilev@...>
Date: 2004-12-09T02:25:05+09:00
Subject: Re: Pointer of pointer with Ruby/DL

Try this:
msgp = DL.malloc(DL.sizeof('P'))
r = Tenant2Auth.public_tenant2_auth_pap_auth("coucou", "titi", msgp.ref)
puts msgp.to_s

Cheers,
Kent.
On Dec 8, 2004, at 10:13 AM, Guillaume Marcais wrote:

> I have the following C prototype:
>
> int auth(char *user, char *passwd, char **msgp);
>
> I pass user and passwd, and I get in response 0 or 1 for success or
> failure and a message in *msgp.
>
> How can i call this function from Ruby using Ruby/DL? So far I did the
> following:
>
> <code>
> module Auth
>   extend DL::Importable
>   dlload "./auth.so"
>   extern "int auth(char *, char *, char **)"
> end
>
> msgp = [0].pack('L').to_ptr
> r = Tenant2Auth.public_tenant2_auth_pap_auth("coucou", "titi", msgp)
> </code>
>
> I get the correct result in 'r'. But how do I get access to the string
> in *msgp?
>
> I guess I don't yet have a good grasp on pointer dereferencing with
> Ruby/DL.
>
> Anyone?
>
> Guillaume.
>
>