2 files changed, 9 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 74e47927b0c..3b5f00a542d 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,7 @@
 2011-04-10  Paul Eggert  <eggert@cs.ucla.edu>
 
+        * xdisp.c (vmessage): Use memchr, not strnlen, which some hosts lack.
+
         Fix more problems found by GCC 4.6.0's static checks.
 
         * xdisp.c (vmessage): Use a better test for character truncation.
diff --git a/src/xdisp.c b/src/xdisp.c
index 6fd3945511b..b0d4b2308a9 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8417,10 +8417,13 @@ vmessage (const char *m, va_list ap)
 
               /* Do any truncation at a character boundary.  */
               if (! (0 <= len && len < bufsize))
-                for (len = strnlen (buf, bufsize);
-                     len && ! CHAR_HEAD_P (buf[len - 1]);
-                     len--)
-                  continue;
+                {
+                  char *end = memchr (buf, 0, bufsize);
+                  for (len = end ? end - buf : bufsize;
+                       len && ! CHAR_HEAD_P (buf[len - 1]);
+                       len--)
+                    continue;
+                }
 
               message2 (FRAME_MESSAGE_BUF (f), len, 0);
             }