* keyboard.c (make_lispy_event): Fix problem in integer overflow.

Don't assume that the difference between two unsigned long values
can fit into an integer.  At this point, we know button_down_time
<= event->timestamp, so the difference must be nonnegative, so
there's no need to cast the result if double-click-time is
nonnegative, as it should be; check that it's nonnegative, just in
case.  This bug is triggered when events are more than 2**31 ms
apart (about 25 days).

1 files changed, 9 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 4d6251f6bde..5760bfc2a1c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,14 @@
 2011-05-12  Paul Eggert  <eggert@cs.ucla.edu>
 
+        * keyboard.c (make_lispy_event): Fix problem in integer overflow.
+        Don't assume that the difference between two unsigned long values
+        can fit into an integer.  At this point, we know button_down_time
+        <= event->timestamp, so the difference must be nonnegative, so
+        there's no need to cast the result if double-click-time is
+        nonnegative, as it should be; check that it's nonnegative, just in
+        case.  This bug is triggered when events are more than 2**31 ms
+        apart (about 25 days).
+
         * xselect.c (last_event_timestamp): Remove duplicate decl.
         (x_own_selection): Remove needless cast to unsigned long.