* xdisp.c (vmessage): Use a better test for character truncation.

2 files changed, 9 insertions, 6 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b5e617b1f20..3bd4fc1f4c0 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,7 @@
 2011-04-09  Paul Eggert  <eggert@cs.ucla.edu>
 
+        * xdisp.c (vmessage): Use a better test for character truncation.
+
         * charset.c (load_charset_map): <, not <=, for optimization,
         and to avoid potential problems with integer overflow.
         * chartab.c (sub_char_table_set_range, char_table_set_range): Likewise.
diff --git a/src/xdisp.c b/src/xdisp.c
index b1209b998e2..f37254419eb 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8410,13 +8410,14 @@ vmessage (const char *m, va_list ap)
             {
               char *buf = FRAME_MESSAGE_BUF (f);
               size_t bufsize = FRAME_MESSAGE_BUF_SIZE (f);
-              int len = vsnprintf (buf, bufsize, m, ap);
-              if (len < 0)
-                len = 0;
+              int len;
+
+              memset (buf, 0, bufsize);
+              len = vsnprintf (buf, bufsize, m, ap);
 
               /* Do any truncation at a character boundary.  */
-              if (0 < bufsize && bufsize <= len)
-                for (len = bufsize - 1;
+              if (! (0 <= len && len < bufsize))
+                for (len = strnlen (buf, bufsize);
                      len && ! CHAR_HEAD_P (buf[len - 1]);
                      len--)
                   continue;
@@ -19495,7 +19496,7 @@ decode_mode_spec (struct window *w, register int c, int field_width,
             EMACS_INT limit = BUF_BEGV (b);
             EMACS_INT limit_byte = BUF_BEGV_BYTE (b);
             EMACS_INT position;
-            EMACS_INT distance = 
+            EMACS_INT distance =
               (height * 2 + 30) * line_number_display_limit_width;
 
             if (startpos - distance > limit)