Re: How many times can I call gtk_label_set_markup()?

[Igor Korot <ikorot01 gmail com>]

David,

2011/4/8 David Nečas <yeti physics muni cz>:
> On Fri, Apr 08, 2011 at 11:00:59AM -0700, Igor Korot wrote:
>> Program received signal SIGABRT, Aborted.
>> [Switching to Thread 0xb7106b40 (LWP 22539)]
>> 0xb805c424 in __kernel_vsyscall ()
>> (gdb) bt
>> #0  0xb805c424 in __kernel_vsyscall ()
>> #1  0xb7169660 in raise () from /lib/libc.so.6
>> #2  0xb716ae98 in abort () from /lib/libc.so.6
>> #3  0xb73d4a31 in g_logv () from /usr/lib/libglib-2.0.so.0
>> #4  0xb73d4ace in g_log () from /usr/lib/libglib-2.0.so.0
>> #5  0xb7477896 in g_type_check_instance_cast () from
>> /usr/lib/libgobject-2.0.so.0
>> #6  0xb7a14e9c in gtk_label_set_markup () from /usr/lib/libgtk-x11-2.0.so.0
>
> So the parameter of gtk_label_set_markup() is bogus, aparently NULL.
> Or, posssibly, something *very* weird happens inside
> gtk_label_set_markup(), maybe if things are already inconsistent at this
> point.
>
> Did you try valgrind?

You're genius. I was able to fix some other stuff. But this one still stands.

Can you see anything wrong in this line:

g_string_printf( m_data1, "<b><span foreground=\"black\"><span
font=\"Sans Serif\"><span
font=\"48\">%2.2f</span></span>V</span></b>", m_totalVoltagePack );

I'm getting from valgrind:

==24358== Invalid write of size 1
==24358==    at 0x4C7DC87: g_string_truncate (in
/usr/lib/libglib-2.0.so.0.1800.4)
==24358==    by 0x4C7DDB1: g_string_printf (in /usr/lib/libglib-2.0.so.0.1800.4)
==24358==    by 0x8049395: CFrame::SetColoring() (main_window.cc:281)
==24358==    by 0x80496D6: CFrame::UpdateData() (main_window.cc:267)
==24358==    by 0x8049842: CFrame::ReadData(CFrame*) (main_window.cc:253)
==24358==    by 0x804A3FC: main (mini2440.cc:37)

And this might be the reason for the null pointer dereference...

Thank you.

>
>> Breakpoint 1, CFrame::UpdateData (this=0x94e1450) at
>> /home/igor/mini2440gtk/mini2440gtk/src/main_window.cc:282
>> 282           gtk_label_set_markup( GTK_LABEL( data2 ), m_data2->str );
>> (gdb) print data1
>> $1 = (GtkWidget *) 0x94e80b0
>
> But the argument is data2, not data1.
>
> Anyway, if everything seems right, the last resort is compiling Gtk+
> from source, idealy with -O0 to get the line numbers precisely, and
> running the program with that to see the exact line where the bad
> typecast occurs.
>
> Yeti
>
>