diff --git a/src/macros.h b/src/macros.h
index 9e3ba44..1737cfa 100644
--- a/src/macros.h
+++ b/src/macros.h
@@ -272,6 +272,7 @@
 
 # define MB_COPY_CHAR(f, t) if (has_mbyte) mb_copy_char(&f, &t); else *t++ = *f++
 # define MB_CHARLEN(p)	    (has_mbyte ? mb_charlen(p) : (int)STRLEN(p))
+# define MB_CHAR2LEN(c)	    (has_mbyte ? mb_char2len(c) : 1)
 # define PTR2CHAR(p)	    (has_mbyte ? mb_ptr2char(p) : (int)*(p))
 #else
 # define MB_PTR2LEN(p)		1
@@ -280,6 +281,7 @@
 # define mb_ptr_back(s, p)	--p
 # define MB_COPY_CHAR(f, t)	*t++ = *f++
 # define MB_CHARLEN(p)		STRLEN(p)
+# define MB_CHAR2LEN(c)		1
 # define PTR2CHAR(p)		((int)*(p))
 #endif