Re: [Liberty-eiffel] Problem with agents

[Paolo Redaelli]

I gave a quick glance at  iup documentation. 
The issue is probably because each feature called foo in an Eiffel class called BAR is translated into a call like 

BARfoo (void *current,..... All the argument of foo) 

The reference (pointer) to Current object is passed as the first argument of the actual function implementation. 

As far as I have read the callback setter in iup does not allow to pass extra arguments that will be given to the callback when invoked (gtk does and we use it to pass the address to Current). 
Is there a way to store a pointer in a iup widget? 

Sorry for the terse answer, I just woke up here in the old side of the ocean (pun intended) and I'm going to work. 
I'll try to be more precise later

Il 22 dicembre 2015 03:09:37 CET, "Germán Arias" <address@hidden> ha scritto:

Hi all,

Well, I'm working in an Eiffel plugin to the library IUP [1]. IUP is a
multi-platform toolkit for building graphical user interfaces, is native
on Windows and on GNU/Linux use Gtk+ (or Mottif). Is MIT License.
Anyway, I'm having a problem with agents, and since I'm newbie in Eiffel
I can't figure where is the problem.

To test this I have a small example as follow:

class EXAMPLE

insert
   -- This expanded class have only one routine which
   -- return a shared object
   IUP_INTERFACE

create {ANY}
   make

feature {ANY}
   make
      local
   gui: IUP
  i: INTEGER
  a: COLLECTION[IUP_WIDGET]
  l: IUP_LABEL
  b: IUP_BUTTON
  v: IUP_VBOX
  w: IUP_DIALOG
      do
         -- The returned object is a shared object
  -- created with a once routine
  gui := iup_open
   
 create
l.label("Hello world from Liberty Eiffel!")
 create b.button("OK", "ACTION")
 gui.iup_set_callback(b, "ACTION", agent display)
 a := {ARRAY[IUP_WIDGET] 0, << l, b >>}

 create v.vbox(a)
 create w.dialog(v)
 gui.set_attribute(w, "TITLE", "Hello world")
 gui.set_attribute(v, "ALIGNMENT", "ACENTER")
 gui.set_attribute(v, "GAP", "10")
 gui.set_attribute(v, "MARGIN", "10x10")
 
 i := w.show

        gui.iup_main
     end

     display
 do
    io.put_string("Executed %N")
 end
end 


Almost all widgets inherit from a class like this (reference class):


feature {ANY}
   widget_pointer: POINTER
   cb_action: ROUTINE[TUPLE]

   widget: POINTER
      do
  Result := widget_pointer
      end

      set_widget (wgt: POINTER)
  do
     widget_pointer := wgt
  end
 
     
set_cb_action (act: ROUTINE[TUPLE])
  do
     cb_action := act
  end

      execute_action
  do
     cb_action.call([])
  end
end

I need store internally the agents because the IUP interface don't let
me pass user data into callbacks.

The shared object (mentioned avobe) have routines to handle callbacks,
like these (this is a reference class):

feature {ANY} -- Commands to handle callbacks
   wer: IUP_WIDGET
 
   iup_set_callback (wgt: IUP_WIDGET; name: STRING; callback:
ROUTINE[TUPLE])
      do
         wer := wgt
         wgt.set_cb_action(callback)
  
         int_set_callback(wgt.widget, name.to_external)
  
         -- This call work here
         -- wer.execute_action
      end

   int_set_callback (object: POINTER; name: POINTER)
      external "plug_in"
      alias "{
         location: "."
     
   module_name: "iup"
         feature_name: "set_callback"
         }"
      end

   launch_routine (obj: POINTER): INTEGER
      do
        wer.execute_action
        Result := 1
      end

For the moment I keep the widget in "wer", but of course I will change
this. The problem is with the agent, stored in the widget with
"wgt.set_cb_action(callback)". If I execute this agent, as shown the
commented lines, this works. But don't work later in "launch_routine".
"launche_routine" is executed by a external call. The program crash here
when try to execute the stored agent. Here the backtrace:


Line : 64 column 8
in /home/german/Instalados/tests/liberty/iup_test/auxiliary/iup.e.
*** Error at Run Time ***: Invalid type for the target of this procedure
call.
4 frames in run-time stack.
====  Bottom of run-time stack  ====
<system root>
Current =
EXAMPLE#0x24f57b8
line 10 column 4
file /home/german/Instalados/tests/liberty/iup_test/example.e 

make EXAMPLE
Current = EXAMPLE#0x24f57b8
gui = IUP#0x27429e8
 [ wer = #0x274d278
 ]
i = 0
a = ARRAY[IUP_WIDGET]#0x2751c88
 [ storage = NATIVE_ARRAY[IUP_WIDGET]#0x2753cb0
   lower = 0
   generation = 1
   capacity = 2
   upper = 1
 ]
l = IUP_LABEL#0x274aa28
 [ cb_action = Void
   widget_pointer = POINTER#0x274ca10
 ]
b = IUP_BUTTON#0x274d278
 [ cb_action = #0x274fc78
   widget_pointer = POINTER#0x274f260
 ]
v = IUP_VBOX#0x275bca8
 [ cb_action = Void
   widget_pointer = POINTER#0x275dc90
 ]
w = IUP_DIALOG#0x275e4a8
 [ cb_action = Void
   widget_pointer = POINTER#0x2760490
 ]
line 36 column 14
file /home/german/Instalados/tests/liberty/iup_test/example.e 

External call (may be a -cecil call).

launch_routine IUP
Current = IUP#0x274f260
 [ wer = #0x26c3270
 ]
obj = POINTER#0x7f7c07ada265
Result = 0
line 64 column 8
file /home/german/Instalados/tests/liberty/iup_test/auxiliary/iup.e 
====  Top of run-time stack   ====
Line : 64 column 8
in /home/german/Instalados/tests/liberty/iup_test/auxiliary/iup.e.
*** Error at Run Time ***: Invalid type for the target of this procedure
call.



What is wrong? Any advice? I attached an image that show how looks this
basic example.

Germán

[1] http://webserver2.tecgraf.puc-rio.br/iup/

-- Inviato dal mio cellulare Android con K-9 Mail.