diff --git a/src/proto/charset.pro b/src/proto/charset.pro
index 0277483..7e515be 100644
--- a/src/proto/charset.pro
+++ b/src/proto/charset.pro
@@ -7,6 +7,7 @@
 char_u *transchar(int c);
 char_u *transchar_buf(buf_T *buf, int c);
 char_u *transchar_byte(int c);
+char_u *transchar_byte_buf(buf_T *buf, int c);
 void transchar_nonprint(buf_T *buf, char_u *charbuf, int c);
 void transchar_hex(char_u *buf, int c);
 int byte2cells(int b);