std::chrono::time_zone::to_sys

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Date and time library

Time point
time_point (C++11)
clock_time_conversion (C++20)
clock_cast (C++20)
Duration
duration (C++11)
Clocks
system_clock (C++11)
steady_clock (C++11)
is_clock (C++20)
utc_clock (C++20)
tai_clock (C++20)
high_resolution_clock (C++11)
gps_clock (C++20)
file_clock (C++20)
local_t (C++20)
Time of day
is_amis_pm (C++20)(C++20)
make12make24 (C++20)(C++20)
hh_mm_ss (C++20)

Calendar
day (C++20)
month (C++20)
year (C++20)
weekday (C++20)
operator/ (C++20)
year_month_day (C++20)
year_month_day_last (C++20)
year_month_weekday (C++20)
year_month_weekday_last (C++20)
weekday_indexed (C++20)
weekday_last (C++20)
month_day (C++20)
month_day_last (C++20)
month_weekday (C++20)
month_weekday_last (C++20)
year_month (C++20)
last_speclast (C++20)(C++20)
`chrono` I/O
parse (C++20)

Time zone
tzdb (C++20)
tzdb_list (C++20)
get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20)
sys_info (C++20)
local_info (C++20)
nonexistent_local_time (C++20)
ambiguous_local_time (C++20)
locate_zone (C++20)
current_zone (C++20)
time_zone (C++20)
choose (C++20)
zoned_traits (C++20)
zoned_time (C++20)
time_zone_link (C++20)
leap_second (C++20)
leap_second_info (C++20)
get_leap_second_info (C++20)
C-style date and time

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std::chrono::time_zone

Member functions
time_zone::name
time_zone::get_info
time_zone::to_sys
time_zone::to_local
Nonmember functions
operator==operator<=>

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template<class Duration> auto to_sys(conststd::chrono::local_time<Duration>& tp)const ->std::chrono::sys_time<std::common_type_t<Duration,std::chrono::seconds>>;	(1)	(since C++20)
template<class Duration> auto to_sys(conststd::chrono::local_time<Duration>& tp,std::chrono::choose z)const ->std::chrono::sys_time<std::common_type_t<Duration,std::chrono::seconds>>;	(2)	(since C++20)

Converts thelocal_timetp in this time zone to the correspondingsys_time.

1) Throws an exception if the conversion is ambiguous or iftp represents a nonexistent time.

2) Resolves ambiguity according to the value ofz:

Ifz== std::chrono::choose::earliest, returns the earliersys_time.
Ifz== std::chrono::choose::latest, returns the latersys_time.

Iftp represents a nonexistent time between two UTCtime_points, those twotime_points will be the same, and thattime_point will be returned.

[edit]Return value

The UTC equivalent oftp according to the rules of this time zone.

[edit]Exceptions

1) Throws:

std::chrono::ambiguous_local_time if the conversion is ambiguous,
std::chrono::nonexistent_local_time iftp represents a nonexistent time.

[edit]Notes

The precision of the result is at leaststd::chrono::seconds, and will be finer if the argument has finer precision.

Ambiguous and nonexistent local times can occur as a result of time zone transitions (such as daylight saving time). For example,"2016-03-13 02:30:00" does not exist in the"America/New_York" time zone, while"2016-11-06 01:30:00" in that time zone can correspond to two UTC time points:2016-11-0605:30:00 UTC and2016-11-0606:30:00 UTC.