gtk::rc_add_default_file
void gtk::rc_add_default_file(string filename); 
    
     Adds a file to the list of files to be parsed at the end of gtk_init().
     The default file to be parsed is ~/.gtkrc. This file
     does not need to be added using gtk::rc_add_default_file() 
     in order to be parsed.
    
    
     See also: gtk::rc_parse()