std::chrono::sys_info (3) - Linux Manuals
Defined in header <chrono>
struct sys_info; (since C++20)
The class sys_info describes time zone information associated with a time zone at a particular point in time (represented as either a std::chrono::sys_time or a std::chrono::local_time). This is a low-level data structure typically not used directly by user code.
Member object Type
begin, end std::chrono::sys_seconds
The begin and end data members indicate the range - [begin, end) - in which the offset and abbrev are in effect for the time zone associated with this sys_info.
The offset and abbrev data member indicate the UTC offset and time zone abbreviation, respectively, in effect for the associated time zone and std::chrono::time_point. Note that time zone abbreviations are not unique.
The save data member, if nonzero, indicates that the time zone is on daylight saving time at the specified time point. In this case, offset - save is a suggestion of what offset this time zone might use if it were off daylight saving time. However, this information is not authoritative: the only way to ascertain the actual offset is to query the time zone with a time point that is actually off daylight savings time (i.e. returns a sys_info such that save == 0min).
operator<< (function template)