ok...even if i'm not an expert...but i think you should have a code like this (into a file called "application_directory/src/interface.c"):
on_connectMainButton_clicked (GtkButton *button,
guint cont_id, id;
static gchar *string="Connecting...";
status = lookup_widget(GTK_WIDGET(obj), "statusbar");
perror("Status bar error");
on_disconnectMainButton_activate (GtkButton *button,
static gchar *string = "i'm disconnecting from server...";
static gchar *title="Disconnecting";
cell_label = lookup_widget(GTK_WIDGET(connecting), "label");
....and so on. At this point you must know and recognize the button you need in some way....and then use it.
if tasks that this code is not similar yours probably your application was written directly with gtk instructions....in this case it's harder to discover the button code you need...
try with some tutorial on internet...but you need to learn a new language....it will be a bit long and difficult....
I hope to you it are of aid