+/* Opens a file handle for writing as a data file.
+
+ The encoding of the file written is by default that of FH itself. If
+ ENCODING is nonnull, then it overrides the default encoding.
+
+ *However*: ENCODING directly affects only text strings written by the data
+ writer code itself, that is, new-lines in FH_MODE_TEXT and space padding in
+ FH_MODE_FIXED mode. The client must do its own encoding translation for the
+ data that it writes. (This is unavoidable because sometimes the data
+ written includes binary data that reencoding would mangle.) The client can
+ obtain the encoding to re-encode into with dfm_writer_get_encoding(). */