[time.zone.info.local]

[Note 1:

This type provides a low-level interface to time zone information.

Typical conversions from local_time to sys_time will use this class implicitly, not explicitly.

— end note]

Describes the result of converting a local_time to a sys_time as follows:

(2.1)
When a local_time to sys_time conversion is unique, result == unique, first will be filled out with the correct sys_info, and second will be zero-initialized.
(2.2)
If the conversion stems from a nonexistent local_time then result == nonexistent, first will be filled out with the sys_info that ends just prior to the local_time, and second will be filled out with the sys_info that begins just after the local_time.
(2.3)
If the conversion stems from an ambiguous local_time, then result == ambiguous, first will be filled out with the sys_info that ends just after the local_time, and second will be filled out with the sys_info that starts just before the local_time.

template<class charT, class traits>
  basic_ostream<charT, traits>&
    operator<(basic_ostream<charT, traits>& os, const local_info& r);

Returns: os.

30 Time library [time]