extern int day_tab[2][13];
-#define isleap(y) (((y % 4) == 0 && (y % 100) != 0) || (y % 400) == 0)
-
-/* Julian date support for date2j() and j2date()
- * Set the minimum year to one greater than the year of the first valid day
- * to avoid having to check year and day both. - tgl 97/05/08
- */
-
-#define JULIAN_MINYEAR (-4713)
-#define JULIAN_MINMONTH (11)
-#define JULIAN_MINDAY (23)
-
-#define IS_VALID_JULIAN(y,m,d) ((y > JULIAN_MINYEAR) \
- || ((y == JULIAN_MINYEAR) && ((m > JULIAN_MINMONTH) \
- || ((m == JULIAN_MINMONTH) && (d >= JULIAN_MINDAY)))))
-
-/*
- * Date/time validation
- * Include check for leap year.
- */
-
-extern int day_tab[2][13];
-
-#define isleap(y) (((y % 4) == 0 && (y % 100) != 0) || (y % 400) == 0)
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
/* Julian date support for date2j() and j2date()
* Set the minimum year to one greater than the year of the first valid day