Creates a copy of @datetime and adds the specified number of months to the
copy. Add negative values to subtract months.
The day of the month of the resulting #GDateTime is clamped to the number
of days in the updated calendar month. For example, if adding 1 month to
31st January 2018, the result would be 28th February 2018. In 2020 (a leap
year), the result would be 29th February.
Creates a copy of @datetime and adds the specified number of months to the copy. Add negative values to subtract months.
The day of the month of the resulting #GDateTime is clamped to the number of days in the updated calendar month. For example, if adding 1 month to 31st January 2018, the result would be 28th February 2018. In 2020 (a leap year), the result would be 29th February.