+ ENCODING must be the encoding of INPUT. Normally this can
+ be obtained by calling dict_get_encoding on the dictionary
+ with which INPUT is associated.
+
+ The return value is dynamically allocated, and must be freed
+ by the caller. If POOL is non-null, then the return value is
+ allocated on that pool.
+*/
+char *
+data_out_pool (const union value *input, const char *encoding,
+ const struct fmt_spec *format, struct pool *pool)