--- /dev/null
+#define rd_wr_wr_off1 (write_off - read_off >= 0)
+#define rd_wr_wr_off2 (write_off - read_off < HALF_UCHAR)
+
+#define commit_sum_wr_off1 (write_off - commit_sum >= 0)
+#define commit_sum_wr_off2 (write_off - commit_sum < HALF_UCHAR)
+
+#define buffer_large_enough (NUMPROCS + NUMSWITCH <= BUFSIZE)
+#define have_events_lost (events_lost != 0)