Hi,
>
> Hello, this all looks like utter voodoo.
Yes it does. I tried 10 other ways and they didn't work. This one works
perfectly (so far).
> You have probably a trivial
> bug somewhere (elsewhere) in your code, maybe some
> extern/static/initialization confusion?
All initialization was shown in the previous examples. All my initializations
are taken directly from the GTK+ documentation and I never had one problem.
More people have been developing this very same application and there was no
problem until I needed to work with the progress bar widget.
There is no static identifier used because it is not needed. The extern
identifier is used only, when the widget is accessed from other files which is
precisely what this identifier was designed for.
> Or you overwrite the stack and
> calling progressBarHack() causes a change of the layout so that you
> overwrite a less sensitive place now?
progressBarHack() does nothing with the layout. All it does is a proper
initialization of the global variable which should work without the hack, but
doesn't.
> Anyway, it is recommended fix to
> avoid global variables, they are evil, and externs are double-evil.
Why? I've personally read the first book on C called The C programming language
from 1978 written by the inventor of the language and using global variables is
explained there as a proper way to implement things. I wonder what is the
source of the 'evil global variables' legend, but if I'm wrong, please correct
me. The extern identifier is just a way to access the global variable from a
different file. I don't see why it should be a double-evil.
> But
> perhaps if you show a minimal *complete* example that exhibits the error
> some will be able to help you. Or, likely, you will find the root cause
> while trying to extract the bad behaviour into a simple example...
I tried to do so in my first email (not the one you responded to). I also
mentioned that I use several widgets as global variables because I need to
access them from multiple functions. Hence, callbacks are not sufficient, in my
opinion.
There was never one problem with using widgets as global variables and the
application uses a lot of them. That's why I think there's a problem
particularly with the Progress bar widget.
My hack just initializes the global variable properly, all it does is
re-initializing the global variable outside the current function stack.
Anywayz, a another simple example:
// global variables
GtkWidget *combobox;
GtkWidget *textField;
GtkWidget *progBar;
GtkWidget* create_main_window (void)
{
.... //necessary window initializations, vertical boxes, tables etc.
combobox = gtk_combo_box_new_text();
gtk_combo_box_append_text(GTK_COMBO_BOX (combobox), (const char*) "U/t");
gtk_combo_box_append_text(GTK_COMBO_BOX (combobox), (const char*) "Q/t");
gtk_combo_box_set_active(GTK_COMBO_BOX (combobox), 0);
gtk_widget_show(combobox);
gtk_box_pack_start (GTK_BOX (vbox3), combobox, FALSE, FALSE, 0);
textField = gtk_text_view_new ();
gtk_widget_show (textField);
gtk_table_attach_defaults(table, textField, 3, 5, 0, 1);
progBar = gtk_progress_bar_new();
gtk_box_pack_start (GTK_BOX (vboxGr), GTK_PROGRESS_BAR(progBar), FALSE,
FALSE, 0);
gtk_widget_show (progBar);
// progressBarHack(progBar);
...
}
All the widgets are used as global variables due to reasons I have explained.
All of them work perfectly and can be accessed from various functions except
the progress bar widget. With the hack, progress bar works perfectly, too.
There are about twenty or more widgets in the application that are used the
same way - as global variables, there's never been one single problem.
Please correct me, if I'm wrong anywhere.
Thanks,
Michael
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