std::localtime

 

C++

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Feature test macros(C++20)

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Concepts library(C++20)

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Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

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Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

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External libraries

 

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

 

C-style date and time utilities

Functions

Time manipulation

difftime

time

clock

timespec_get (C++17)

Format conversions

asctime

ctime

strftime

wcsftime

gmtime

localtime

mktime

Constants

CLOCKS_PER_SEC

Types

tm

time_t

clock_t

timespec (C++17)

 

Defined in header <ctime>
std::tm* localtime(conststd::time_t* time );

Converts given time since epoch as std::time_t value into calendar time, expressed in local time.

Parameters

time

-

pointer to a std::time_t object to convert

Return value

Pointer to a static internal std::tm object on success, or null pointer otherwise. The structure may be shared between std::gmtime, std::localtime, and std::ctime, and may be overwritten on each invocation.

Notes

This function may not be thread-safe.

POSIX requires that this function sets errno to EOVERFLOW if it fails because the argument is too large.

POSIX specifies that the timezone information is determined by this function as if by calling tzset, which reads the environment variable TZ.

Example

Run this code

#include <ctime>#include <iomanip>#include <iostream>#include <sstream>   int main(){ setenv("TZ", "/usr/share/zoneinfo/America/Los_Angeles", 1);// POSIX-specific   std::tm tm{};// Zero initialise tm.tm_year=2020-1900;// 2020 tm.tm_mon=2-1;// February tm.tm_mday=15;// 15th tm.tm_hour=10; tm.tm_min=15; tm.tm_isdst=0;// Not daylight savingstd::time_t t =std::mktime(&tm);   std::cout<<"UTC: "<<std::put_time(std::gmtime(&t), "%c %Z")<<'\n';std::cout<<"local: "<<std::put_time(std::localtime(&t), "%c %Z")<<'\n';}

Possible output:

UTC: Sat Feb 15 18:15:00 2020 GMT local: Sat Feb 15 10:15:00 2020 PST

See also

gmtime	converts time since epoch to calendar time expressed as Universal Coordinated Time (function)
localtimelocaltime_rlocaltime_s (C23)(C11)	converts time since epoch to calendar time expressed as local time (function)
C documentation for localtime