This functionality has been made obsolete by newer, better solved CDateTime available directly in core instead.
The DT_IsLeapYear () function converts a given number of seconds to the correspondent time string.
DT_IsLeapYear(nYear AS NUMBER) AS NUMBER
Returns AS NUMBER
If the year is leap the return value is nonzero.
If the year isn't leap, the return value is zero.
nYear AS NUMBER
IF DT_IsLeapYear(2004) THEN
MSGBOX 0, "Year 2004 is leap." ' results: Year 2004 is leap.