(MAKE_CHAR_MULTIBYTE): Check the arg is a (uni)byte.

2 files changed, 4 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 178e5b38969..c564066d0b2 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,7 @@
 2008-06-05  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * character.h (MAKE_CHAR_MULTIBYTE): Check the arg is a (uni)byte.
+
         * keymap.c (Vminibuffer_local_filename_must_match_map):
         Rename from Vminibuffer_local_must_match_filename_map.
         (syms_of_keymap):
diff --git a/src/character.h b/src/character.h
index ce36cdf85ff..ae87b3885d9 100644
--- a/src/character.h
+++ b/src/character.h
@@ -95,7 +95,8 @@ extern char unibyte_has_multibyte_table[256];
 
 
 /* If C is not ASCII, make it multibyte.  It assumes C < 256.  */
-#define MAKE_CHAR_MULTIBYTE(c) ((c) = unibyte_to_multibyte_table[(c)])
+#define MAKE_CHAR_MULTIBYTE(c) \
+  (eassert ((c) >= 0 && (c) < 256), (c) = unibyte_to_multibyte_table[(c)])
 
 /* This is the maximum byte length of multibyte form.  */
 #define MAX_MULTIBYTE_LENGTH 5