Most ZOOM objects provide a way to specify options to change behavior. From an implementation point of view a set of options is just like an associative array / hash.

     ZOOM_options ZOOM_options_create(void);

     ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);

     void ZOOM_options_destroy(ZOOM_options opt);
   

     const char *ZOOM_options_get(ZOOM_options opt, const char *name);

     void ZOOM_options_set(ZOOM_options opt, const char *name,
                           const char *v);
   

     typedef const char *(*ZOOM_options_callback)
                            (void *handle, const char *name);

     ZOOM_options_callback
             ZOOM_options_set_callback(ZOOM_options opt,
                                       ZOOM_options_callback c,
                                       void *handle);