size_t (*size) (gl_oset_t set);
bool (*search) (gl_oset_t set, const void *elt);
bool (*search_atleast) (gl_oset_t set,
gl_setelement_threshold_fn threshold_fn,
const void *threshold, const void **eltp);
size_t (*size) (gl_oset_t set);
bool (*search) (gl_oset_t set, const void *elt);
bool (*search_atleast) (gl_oset_t set,
gl_setelement_threshold_fn threshold_fn,
const void *threshold, const void **eltp);