X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/26e06f4464c58704889bdc536edc25b73e8c0179..986fb647cc1df1edeeaa2c0e7cb34c100eb9efb9:/src/systime.h

diff --git a/src/systime.h b/src/systime.h
index 2a04beff75..2f8d35805a 100644
--- a/src/systime.h
+++ b/src/systime.h
@@ -1,6 +1,6 @@
 /* systime.h - System-dependent definitions for time manipulations.
    Copyright (C) 1993, 1994, 2002, 2003, 2004,
-                 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+                 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -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.  */