-#define EV_UNDEF -1 /* guaranteed to be invalid */
-#define EV_NONE 0x00
-#define EV_READ 0x01
-#define EV_WRITE 0x02
-#define EV_TIMEOUT 0x000100
-#define EV_PERIODIC 0x000200
-#define EV_SIGNAL 0x000400
-#define EV_IDLE 0x000800
-#define EV_CHECK 0x001000
-#define EV_PREPARE 0x002000
-#define EV_CHILD 0x004000
-#define EV_ERROR 0x800000 /* sent when an error occurs */
-
-/* can be used to add custom fields to all watchers */
+#define EV_UNDEF -1L /* guaranteed to be invalid */
+#define EV_NONE 0x00L
+#define EV_READ 0x01L /* io only */
+#define EV_WRITE 0x02L /* io only */
+#define EV_TIMEOUT 0x000100L /* timer only */
+#define EV_PERIODIC 0x000200L /* periodic timer only */
+#define EV_SIGNAL 0x000400L /* signal only */
+#define EV_IDLE 0x000800L /* idle only */
+#define EV_CHECK 0x001000L /* check only */
+#define EV_PREPARE 0x002000L /* prepare only */
+#define EV_CHILD 0x004000L /* child/pid only */
+#define EV_ERROR 0x800000L /* sent when an error occurs */
+
+/* can be used to add custom fields to all watchers, while losing binary compatibility */