std:: tm

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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) [note 1]
(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)
  1. ↑ Range allows for a positive leap second. Two leap seconds in the same minute are not allowed (the range [ ​ 0 ​ , 61 ] was a defect introduced in C89 and corrected in C99).

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

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