To: lablgtk at kaba.or.jp
Subject: strange data problems
From: Michael Welsh Duggan <md5i at cs.cmu.edu>
Date: Sat, 31 May 2003 19:08:26 -0400
Message-ID: <874r3aemtx.fsf at cs.cmu.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Sender: Michael Welsh Duggan <md5i at md5i.dsl.telerama.com>

Using lablgtk2, the program at
<URL:http://md5i.dsl.telerama.com:8000/timeagent/> fails under very
strange circumstances.  Try compiling and running the program.  You
should get a window that looks like
<URL:http://md5i.dsl.telerama.com:8000/timeagent/ui1.png>.

Now, middle-click on the hex that is marked in 
<URL:http://md5i.dsl.telerama.com:8000/timeagent/ui2.png>.  That
should turn over the tile.  If you middle click on the tile again,
the program segfaults.  I have been unable to determine why.  I am
trying to create an isolated example, but I have not yet been able
to.  

I put an abort in ml_lookup_from_c before the error gets thrown.  The
backtrace is as follows:

#0  0x4044da41 in kill () from /lib/libc.so.6
#1  0x4044d862 in raise () from /lib/libc.so.6
#2  0x4044e976 in abort () from /lib/libc.so.6
#3  0x080d32a5 in ml_lookup_from_c (table=0x40533f60, data=6) at wrappers.c:84
#4  0x080d88fd in ml_GdkEventCrossing_mode (val=0) at ml_gdk.c:754
#5  0x080608b4 in Ui__fun_1894 ()
#6  0x080d3bd1 in marshal (closure=0x0, ret=0x407758b0, nargs=0, 
    args=0xbffff6c8, hint=0xbffff5d0, marshall_data=0x0) at ml_gobject.c:74
#7  0x40396956 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#8  0x403a6406 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#9  0x403a5395 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#10 0x403a575b in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#11 0x400402f9 in gnome_canvas_new_aa () from /usr/lib/libgnomecanvas-2.so.0
#12 0x40040604 in gnome_canvas_new_aa () from /usr/lib/libgnomecanvas-2.so.0
#13 0x4004169b in gnome_canvas_new_aa () from /usr/lib/libgnomecanvas-2.so.0
#14 0x4004179a in gnome_canvas_new_aa () from /usr/lib/libgnomecanvas-2.so.0
#15 0x403e6be8 in g_timeout_add () from /usr/lib/libglib-2.0.so.0
#16 0x403e444f in g_get_current_time () from /usr/lib/libglib-2.0.so.0
#17 0x403e5369 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#18 0x403e566f in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#19 0x403e5878 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#20 0x080d4bb1 in ml_g_main_iteration (arg1=137024848) at ml_glib.c:140

The values for ml_lookup_from_c are nonsensical.  The table
(ml_table_gdkCrossingMode) doesn't exist at that location, and 6 is
well outside the range of a crossing mode.  Any sugegstions on how to
debug this?

(Sorry about the messy code.  Much of it is experimental, and it has
been hacked to oblivion.)

-- 
Michael Welsh Duggan
(md5i@cs.cmu.edu)