1 files changed, 4 insertions, 0 deletions

diff --git a/src/charset.h b/src/charset.h
index 34540c3d201..d2fd94e6ade 100644
--- a/src/charset.h
+++ b/src/charset.h
@@ -553,6 +553,9 @@ extern int iso_charset_table[2][2][128];
 
 #define BASE_LEADING_CODE_P(c) (BYTES_BY_CHAR_HEAD ((unsigned char) (c)) > 1)
 
+/* Return how many bytes C will occupy in a multibyte buffer.  */
+#define CHAR_BYTES(c) (SINGLE_BYTE_CHAR_P (c) ? 1 : char_bytes (c))
+
 /* The following two macros CHAR_STRING and STRING_CHAR are the main
    entry points to convert between Emacs two types of character
    representations: multi-byte form and single-word form (character
@@ -815,6 +818,7 @@ extern int cmpchar_component P_ ((unsigned int, unsigned int));
 extern int find_charset_in_str P_ ((unsigned char *, int, int *,
                                     Lisp_Object, int));
 extern int strwidth P_ ((unsigned char *, int));
+extern int char_bytes P_ ((int));
 
 extern Lisp_Object Vtranslation_table_vector;