std::tm

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)

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

#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

localtimelocaltime_r (C++26)	converts time since epoch to calendar time expressed as local time (function)
gmtimegmtime_r (C++26)	converts time since epoch to calendar time expressed as Universal Coordinated Time (function)
C documentation for `tm`

std::tm

Member objects

Notes

Example

See also