for (; notmuch_filenames_valid(fnames); notmuch_filenames_move_to_next(fnames))
rb_yield(rb_str_new2(notmuch_filenames_get(fnames)));
for (; notmuch_filenames_valid(fnames); notmuch_filenames_move_to_next(fnames))
rb_yield(rb_str_new2(notmuch_filenames_get(fnames)));