View source code
Display the source code in std/datetime/date.d from which this page was generated on github.
Report a bug
If you spot a problem with this page, click here to create a Bugzilla issue.
Improve this page
Quickly fork, edit online, and submit a pull request for this page. Requires a signed-in GitHub account. This works well for small changes. If you'd like to make larger changes you may want to consider using local clone.


Adds the given number of years or months to this Date, mutating it. A negative number will subtract.

ref Date add(string units) (
  long value,
  AllowDayOverflow allowOverflow = AllowDayOverflow.yes
) pure nothrow @nogc @safe
if (units == "years");

Note that if day overflow is allowed, and the date with the adjusted year/month overflows the number of days in the new month, then the month will be incremented by one, and the day set to the number of days overflowed. (e.g. if the day were 31 and the new month were June, then the month would be incremented to July, and the new day would be 1). If day overflow is not allowed, then the day will be set to the last valid day in the month (e.g. June 31st would become June 30th).


units The type of units to add ("years" or "months").
value The number of months or years to add to this Date.
allowOverflow Whether the day should be allowed to overflow, causing the month to increment.


A reference to the Date (this).


auto d1 = Date(2010, 1, 1);
writeln(d1); // Date(2010, 12, 1)

auto d2 = Date(2010, 1, 1);
writeln(d2); // Date(2009, 2, 1)

auto d3 = Date(2000, 2, 29);
writeln(d3); // Date(2001, 3, 1)

auto d4 = Date(2000, 2, 29);
writeln(d4); // Date(2001, 2, 28)


Jonathan M Davis


Boost License 1.0.