--- a/src/c/file.d
+++ b/src/c/file.d
@@ -3068,7 +3068,7 @@
 		return (flags & ~ECL_STREAM_FORMAT) | ECL_STREAM_USER_FORMAT;
 	}
 	if (ECL_SYMBOLP(format)) {
-		format = _ecl_funcall2(@'ext::make-encoding', format);
+		format = si_make_encoding(format);
 		if (ECL_SYMBOLP(format))
 			goto PARSE_SYMBOLS;
 		stream->stream.format_table = format;