Re: GNAT linker error

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Sun, 25 Jan 2015 15:15:32 -0800 (PST), hosszu.gabor90@gmail.com wrote:

> Thank you, adding -lpixman-1 made it work. But please explain me how it can happen that:
> - with GPS 5 it worked without lib pixman linker flag
> - "manually" it also worked
> - both of these mean execution of the following command: (I have compared them)
> gnatmake -d -P/home/myuser/own_projects/ada/AdaTest.gpr -vP2 -j4 -g
> So everything depends only on the project files (AdaTest.gpr and gtkada.gpr) which do not contain anything related to pixman.
> 
> And the program is this simple GtkAda example:
> 
> with Gtk.Box;         use Gtk.Box;
> with Gtk.Button;      use Gtk.Button;
> with Gtk.Label;       use Gtk.Label;
> with Gtk.Widget;      use Gtk.Widget;
> with Gtk.Main;
> with Gtk.Window;      use Gtk.Window;
> with Gtkada.Handlers; use Gtkada.Handlers;
> with Ada.Text_IO;
> with Glib; use Glib;
> procedure Main is
>    Win   : Gtk_Window;
>    Label : Gtk_Label;
>    Box   : Gtk_Vbox;
> begin
>    Gtk.Main.Set_Locale;
>    Gtk.Main.Init;
>    Gtk_New (Win);
>    Win.Set_Default_Size (500, 500);
>    Gtk_New_Vbox (Box);
>    Gtk_New (Label, "Hello world.");
>    Win.Add (Label);
>    Win.Show_All;
>    Gtk.Main.Main;
> end Main;

Pixman is related to cairo and cairo since GTK 3.x is the drawing engine
behind the GTK. Prior to 3.x, in 2.x it was custom GDK drawing used for
this. I don't remember if GDK drawing ever used pixman. So I suspect you
may have versions mismatch.

BTW, the example is incomplete. It does not have the destroy handler
attached needed to jump out of the events loop when you close the
application window through the window manager. The effect should be that
the window will be closed but the process still running.

The test refers to Gtkada.Handlers, but does not use it to connect to the
Destroy event. OK, it could not anyway due to accessibility issues. The
handler must be declared in a package at the library level. It would not
compile if you place it in the procedure Main.

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