* fileio.c (Fverify_visited_file_modtime): Avoid time overflow

if b->modtime has its maximal value.

2 files changed, 4 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 4269bf4655b..f86b0decf3c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,8 @@
 2011-06-06  Paul Eggert  <eggert@cs.ucla.edu>
 
+        * fileio.c (Fverify_visited_file_modtime): Avoid time overflow
+        if b->modtime has its maximal value.
+
         * dired.c (Ffile_attributes): Don't assume EMACS_INT has >32 bits.
 
         Don't assume time_t can fit into int.
diff --git a/src/fileio.c b/src/fileio.c
index 94894b97a6e..48dac80a39f 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4960,7 +4960,7 @@ See Info node `(elisp)Modification Time' for more details.  */)
   if ((st.st_mtime == b->modtime
        /* If both are positive, accept them if they are off by one second.  */
        || (st.st_mtime > 0 && b->modtime > 0
-           && (st.st_mtime == b->modtime + 1
+           && (st.st_mtime - 1 == b->modtime
                || st.st_mtime == b->modtime - 1)))
       && (st.st_size == b->modtime_size
           || b->modtime_size < 0))