(EMACS_TIME_CMP): Cast EMACS_SECS values to `long'.

2 files changed, 10 insertions, 6 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 484dfc605d8..50057069c0c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,7 @@
 2008-10-04  Eli Zaretskii  <eliz@gnu.org>
 
+        * systime.h (EMACS_TIME_CMP): Cast EMACS_SECS values to `long'.
+
         * dispnew.c (change_frame_size_1): Set FrameRows and FrameCols for
         MSDOS frames as well.
 
diff --git a/src/systime.h b/src/systime.h
index 2a04beff757..aa1f5d329f0 100644
--- a/src/systime.h
+++ b/src/systime.h
@@ -150,12 +150,14 @@ extern Lisp_Object make_time __P ((time_t));
 #endif
 
 /* Compare times T1 and T2.  Value is 0 if T1 and T2 are the same.
-   Value is < 0 if T1 is less than T2.  Value is > 0 otherwise.  */
-
-#define EMACS_TIME_CMP(T1, T2)                  \
-  (EMACS_SECS (T1) - EMACS_SECS (T2)            \
-   + (EMACS_SECS (T1) == EMACS_SECS (T2)        \
-      ? EMACS_USECS (T1) - EMACS_USECS (T2)     \
+   Value is < 0 if T1 is less than T2.  Value is > 0 otherwise.  (Cast
+   to long is for those platforms where time_t is an unsigned
+   type, and where otherwise T1 will always be grater than T2.)  */
+
+#define EMACS_TIME_CMP(T1, T2)                          \
+  ((long)EMACS_SECS (T1) - (long)EMACS_SECS (T2)        \
+   + (EMACS_SECS (T1) == EMACS_SECS (T2)                \
+      ? EMACS_USECS (T1) - EMACS_USECS (T2)             \
       : 0))
 
 /* Compare times T1 and T2 for equality, inequality etc.  */