std::tm

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

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>
struct tm;

Structure holding a calendar date and time broken down into its components.

Member objects

int tm_sec	seconds after the minute – [​0​, 61](until C++11) [​0​, 60](since C++11) (public member object)
int tm_min	minutes after the hour – [​0​, 59] (public member object)
int tm_hour	hours since midnight – [​0​, 23] (public member object)
int tm_mday	day of the month – [1, 31] (public member object)
int tm_mon	months since January – [​0​, 11] (public member object)
int tm_year	years since 1900 (public member object)
int tm_wday	days since Sunday – [​0​, 6] (public member object)
int tm_yday	days since January 1 – [​0​, 365] (public member object)
int tm_isdst	Daylight Saving Time flag. The value is positive if DST is in effect, zero if not and negative if no information is available. (public member object)

Notes

BSD, GNU and musl C library support two additional members, which are standardized in POSIX.1-2024.

long tm_gmtoff	seconds east of UTC (public member object)
const char* tm_zone	timezone abbreviation (public member object)

Example

Run this code

#include <ctime>
#include <iostream>
 
int main()
{
    std::tm tm{};
    tm.tm_year = 2022 - 1900;
    tm.tm_mday = 1;
    std::mktime(&tm);
 
    std::cout << std::asctime(&tm); // note implicit trailing '\n'
}

Possible output:

Sat Jan  1 00:00:00 2022

See also

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