From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED.2uCIJahv+a4XEBqttj5Vkw.user.gioia.aioe.org!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: generic provokes segmentation fault
Date: Mon, 18 May 2020 23:30:35 +0200
Organization: Aioe.org NNTP Server
Message-ID: <r9uupp$32m$1@gioia.aioe.org>
References: <hicvepF6b7sU1@mid.individual.net> <r9s02u$j01$1@gioia.aioe.org>
 <hif9t7Fl54uU1@mid.individual.net> <r9tvh9$1l2u$1@gioia.aioe.org>
 <hig8olFrhghU1@mid.individual.net>
NNTP-Posting-Host: 2uCIJahv+a4XEBqttj5Vkw.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101
 Thunderbird/68.8.0
Content-Language: en-US
X-Notice: Filtered by postfilter v. 0.9.2
Xref: reader01.eternal-september.org comp.lang.ada:58740
Date: 2020-05-18T23:30:35+02:00
List-Id: <comp.lang.ada>

On 2020-05-18 22:16, hreba wrote:
> On 2020-05-18 14:36, Dmitry A. Kazakov wrote:
> 
>> What is global variables you are talking about? gsl_odeiv2_driver 
>> seems to be allocated and initialized using library functions.
> 
> Initially, I tried the following:
> 
>   - the library defines a type with that driver as a private component
>   - the client declares a variable of that type
>   - the client calls the library's initialization function, which
>     instanciates this variable (and the driver within)
> 
> I just was not able to get around that local/non-local object/pointer 
> problem, and for now the driver is a global variable hidden in the 
> library, initialized as a side effect of Init_Solve, as a workaround.

This what possibly crashes it because you don't not use official 
"constructors".

As I said it should be kind of

    type Driver is new Ada.Finalization.Limited_Controlled with private;
    procedure Apply (Object : in out Driver; ...);
    procedure Set (Object : in out Driver; ...); -- Set standard driver
    procedure Set (Object : in out Driver; ...); -- Set scaled driver
    ...
    overriding procedure Finalize (Object : in out Driver);
private
    type gsl_odeiv2_driver_struct is record ... end record;
    pragma Convention (C, gsl_odeiv2_driver_struct);
    type gsl_odeiv2_driver is access all gsl_odeiv2_driver_struct;
    pragma Convention (C, gsl_odeiv2_driver);

    type Driver is new Ada.Finalization.Limited_Controlled with record
       odeiv2 : gsl_odeiv2_driver;
    end record;

    procedure Set (Object : in out Driver; ...) is
    begin
       if Object.odeiv2 /= null then              -- Delete old, if any
          gsl_odeiv2_driver_free (Object.odeiv2); -- Could store and
          Object.odeiv2 := null;                  -- check its type
       end if;
       Object.odeiv2 := gsl_odeiv2_driver_alloc_standard_new (...);
    end Set ;

    procedure Finalize (Object : in out Driver) is
    begin
       if Object.odeiv2 /= null then
          gsl_odeiv2_driver_free (Object.odeiv2);
          Object.odeiv2 := null;
       end if;
    end Initialize;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de