+=head2 Limits of time_t
+
+On perl versions older than 5.12.0, the range of dates that can be
+actually be handled depends on the size of C<time_t> (usually a signed
+integer) on the given platform. Currently, this is 32 bits for most
+systems, yielding an approximate range from Dec 1901 to Jan 2038.
+
+Both C<timelocal()> and C<timegm()> croak if given dates outside the
+supported range.
+
+As of version 5.12.0, perl has stopped using the underlying time
+library of the operating system it's running on and has its own
+implementation of those routines with a safe range of at least
++/ 2**52 (about 142 million years).
+