OpenEuphoria

1. EuGTK - GtkDrawingArea

• Posted by Jerry_Story Oct 10, 2010
• 1314 views

/usr/share/euphoria/include/std/sequence.e:1375 in function vslice() A machine-level exception occurred during execution of this statement
... called from ./eugtk_stuff/GtkEngine.e:188 in function lookup_object_class_from_handle()

... called from ./eugtk_stuff/GtkEngine.e:484 in procedure set()

... called from ./dmak_actions.e:22 in procedure setFoodColors()

This is line 22.

set(drwColorBand1,"modify bg",0,"white")

drwColorBand1 is a GtkDrawingArea.

drwColorBand1 = create(GtkDrawingArea)

This time I'm showing everything with
show_all(Win)

What is wrong with line 22?

3. Re: EuGTK - GtkDrawingArea

• Posted by irv Oct 10, 2010
• 1286 views

? drwColorBand1 
set(drwColorBand1,"modify bg",0,"white") 

The first thing to do when something goes wrong is to inspect the object handle to see if it's valid.

The first line above should print some large integer, like 151824384. Zero means the object doesn't exist or hasn't been "realized" yet.

I don't suspect that is the problem here, but it's always good (easy too) to check that first.

------------------------------------------------------------- 
export function lookup_object_class_from_handle(atom handle) 
------------------------------------------------------------- 
? object_register -- (1) 
object list = vslice(object_register,1) 

The problem seems to be here, so I would add line (1) to your GtkEngine.e file, and see what the object_register looks like.

{ 
  {168724008,35}, 
  {170355912,29}, 
  {170355608,29}, 
  {170355456,29},... 

You should get something like the above, a sequence of {handle,id}. Apparently, somewhere along the line, you're getting a bogus atom thrown in there. I can't think how that can happen, because that particular error hasn't ever occurred for me.

Do the above, and post the offending part of the list.

5. Re: EuGTK - GtkDrawingArea

• Posted by Jerry_Story Oct 10, 2010
• 1292 views

------------------------------------------------------------- 
export function lookup_object_class_from_handle(atom handle) 
------------------------------------------------------------- 
ifdef LOOK then 
	? object_register 
end ifdef 
object list = vslice(object_register,1) 
integer x = find(handle,list) 
if x then  
	ifdef LOOK then 
		printf(1,"LOOKUP OBJ CLASS FROM HANDLE: class: %d handle:%d\n",{x,handle}) 
	end ifdef 
	return object_register[x][CLASS] 
else 
	return -1 
end if 
end function 

jstory@jstory-desktop:/media/usb1_/projects/eugtk-projects/dmak-gtk$ eui dmak.exw -d LOOK

/usr/share/euphoria/include/std/sequence.e:1375 in function vslice()
A machine-level exception occurred during execution of this statement

... called from ./eugtk_stuff/GtkEngine.e:188 in function lookup_object_class_from_handle()

... called from ./eugtk_stuff/GtkEngine.e:484 in procedure set()

... called from ./dmak_actions.e:22 in procedure setFoodColors()

7. Re: EuGTK - GtkDrawingArea

• Posted by Jerry_Story Oct 10, 2010
• 1270 views

Made a mistake. Forgot to copy the changed GtkEngine.e to the project directory.

jstory@jstory-desktop:/media/usb1_/projects/eugtk-projects/dmak-gtk$ eui dmak.exw -d LOOK /usr/share/euphoria/include/std/sequence.e:1375 in function vslice()
A machine-level exception occurred during execution of this statement

... called from ./eugtk_stuff/GtkEngine.e:207 in function lookup_object_class_from_handle()

... called from ./eugtk_stuff/GtkEngine.e:504 in procedure set()

... called from ./dmak_actions.e:22 in procedure setFoodColors()

Line 207 is
object list = vslice(object_register,1)

9. Re: EuGTK - GtkDrawingArea

• Posted by Jerry_Story Oct 11, 2010
• 1284 views

The plot thickens.

Sometimes instead of getting an error on line 22, I get an error on line 717.

/usr/share/euphoria/include/std/sequence.e:1375 in function vslice()
A machine-level exception occurred during execution of this statement

... called from ./eugtk_stuff/GtkEngine.e:207 in function lookup_object_class_from_handle()

... called from ./eugtk_stuff/GtkEngine.e:593 in function get()

... called from ./dmak_actions.e:717 in procedure Sort_dlNutrients()

if (gtk:get(MenuNSI,"active") = TRUE) then

This Line 717.

MenuNSI = create(GtkCheckMenuItem,"new_with_label=>Sort normally."),

MenuNSI is a GtkCheckMenuItem.

Apart from line 1375 and line 207, I have no idea what the similarity is.

? drwColorBand1 
? MenuNSI 

Both of these produce a large number.

11. Re: EuGTK - GtkDrawingArea

• Posted by mattlewis (admin) Oct 11, 2010
• 1258 views

This is fixed in the current trunk as of svn:3491.

Matt

13. Re: EuGTK - GtkDrawingArea

• Posted by mattlewis (admin) Oct 11, 2010
• 1255 views

I'm getting an error in t_safe.e (interpreted) and t_literals.e (translating), but I didn't think it was related to that issue.

Matt

15. Re: EuGTK - GtkDrawingArea

• Posted by mattlewis (admin) Oct 11, 2010
• 1215 views

Well, yes and no. I agree that the user of a library shouldn't have to rearrange include order, but in this case, there's not really another alternative. It's simply a case of when certain code executes. One statement must be either before or after another. And if statement B must follow statement A, but does not, you'll get an error, like we had here.

Here was the basic issue:

-- file_a.e 
 
include file_b.e 
 
export constant foo = call_some_function() 
 
-- ....code... 
 
-- file_b.e 
include file_a.e 
 
? foo 
 

In this case, if your code includes file_b.e first, it should work, because foo should be initialized before we try to print it. However, if you include file_a.e first, before foo can be initialized, file_b.e is included, and it attempts to use foo.

To fix this:

-- file_a.e 
 
export constant foo = call_some_function() 
include file_b.e 
 
-- ....code... 
 
-- file_b.e 
include file_a.e 
 
? foo 
 

...and now, foo is definitely initialized prior to being used in file_b.e, regardless of how those files were included into a program. So I think that as a general practice, top level initializations should be done as soon as possible, and with minimum includes preceding them in the file.

Matt