* fns.c (Fstring_to_unibyte): Don't rely on undefined behavior

by passing a long int to a printf format expecting an int.

2 files changed, 7 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 185d611ea6e..fd864a460f4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -2,6 +2,9 @@
 
         Fix more problems found by GCC 4.6.0's static checks.
 
+        * fns.c (Fstring_to_unibyte): Don't rely on undefined behavior
+        by passing a long int to a printf format expecting an int.
+
         * lisp.h (message, message_nolog, doprint, error, verror, fatal):
         Mark as printf-like functions.
 
diff --git a/src/fns.c b/src/fns.c
index c45d9e31ef2..ca18dbfc100 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -1076,7 +1076,10 @@ an error is signaled.  */)
       EMACS_INT converted = str_to_unibyte (SDATA (string), str, chars, 0);
 
       if (converted < chars)
-        error ("Can't convert the %dth character to unibyte", converted);
+        {
+          long lconverted = converted;
+          error ("Can't convert the %ldth character to unibyte", lconverted);
+        }
       string = make_unibyte_string ((char *) str, chars);
       xfree (str);
     }