Re: date overflow in year 2038

[James Youngman]

On Sat, Feb 14, 2009 at 3:45 AM, David M. Dowdle
<address@hidden> wrote:
>
> I'd rank this as low priority, but people doing things like 30 year mortages
> will be hitting this already.
>

Mortgage calculations probably shouldn't be using time_t anyway; use
of time_t for future calculations assumes that we already know how
long each year is going to be, to the nearest second[1].    Mortgage
agreements on the other hand specify dates in civil time and therefore
the duration of the agreement in seconds can't be precisely known when
the agreement is signed.

For example were I to take out a mortgage that starts in December but
ends on 1st April 2039, the actual length of the mortgage (as
putatively measured by using time_t) would depend both on the leap
seconds occurring between now and then and also the summer-time
regulations in effect in 2039, which nobody has any way of predicting
right now.

James.


[1] ... or that the precise alignment between future values of time_t
and calendar time doesn't matter much