problem with gtk_signal_func and gtkentry() in gtk1.2

[Marcus vA <mva121 gmx net>]

Hello, 

I've a big problem with a GTK_SIGNAL_FUNC
and GtkEntry(). The main problem to solve, was to let the user make 
some input in two entry-boxes and write this in a file.

<snippet>
gnome_dialog_button_connect(GNOME_DIALOG(editor),
                                                            0,
                                                           GTK_SIGNAL_FUNC(add_entry_cb(
                                                                                                              
  lang_from,
                                                                                                              
  lang_to,
                                                                                                              
  gtk_entry_get_text(GTK_ENTRY(edit_from)),
                                                                                                              
  gtk_entry_get_text(GTK_ENTRY(edit_to)))),
                                                              NULL);

</snippet>

here comes the add_entry_cb:

void add_entry_cb(gchar *trans_from_lng, gchar *trans_to_lang,
                  gchar *edit_from_lng, gchar *edit_to_lng){
<....>
}

All headers and Makefiles are correct, all headers, which are necessary, are included.

when I try to compile this, the following error occurs:

121: void value not ignored as it ought to be

line 121 is 
   gtk_entry_get_text(GTK_ENTRY(edit_to)))),

Does anyone know how to get this fixed?
I'm new to gtk, so any help or suggestions are wanted.

Thanks 

Marcus