-@deftypefun void data_out (const union value *@var{input}, const struct fmt_spec *@var{format}, char *@var{output})
-@deftypefunx void data_out_legacy (const union value *@var{input}, enum legacy_encoding @var{legacy_encoding}, const struct fmt_spec *@var{format}, char *@var{output})
-Converts the data pointed to by @var{input} into a data field in
-@var{output} according to output format specifier @var{format}, which
-must be a valid output format. Exactly @code{@var{format}->w} bytes
-are written to @var{output}. The width of @var{input} is also
+@deftypefun char * data_out (const union value *@var{input}, const struct fmt_spec *@var{format})
+@deftypefunx char * data_out_legacy (const union value *@var{input}, const char *@var{encoding}, const struct fmt_spec *@var{format})
+Converts the data pointed to by @var{input} into a string value, which
+will be encoded in UTF-8, according to output format specifier @var{format}.
+Format
+must be a valid output format. The width of @var{input} is