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tm

Defined in header `<time.h>`
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 C99) / [0, 60] (since C99)^{[note 1]}
int tm_min	minutes after the hour – [0, 59]
int tm_hour	hours since midnight – [0, 23]
int tm_mday	day of the month – [1, 31]
int tm_mon	months since January – [0, 11]
int tm_year	years since 1900
int tm_wday	days since Sunday – [0, 6]
int tm_yday	days since January 1 – [0, 365]
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

Notes

Range allows for a positive leap second. Two leap seconds in the same minute are not allowed (the C90 range 0..61 was a defect)

Example

Show the start of calendar time.

#include <stdio.h>
#include <time.h>
 
int main(void)
{
    struct tm start = {.tm_mday=1};
    mktime(&start);
    printf("%s\n", asctime(&start));
}

Possible output:

Mon Jan  1 00:00:00 1900

References

C11 standard (ISO/IEC 9899:2011):

7.27.1/3 Components of time (p: 388)

C99 standard (ISO/IEC 9899:1999):

7.23.1/3 Components of time (p: 338)

C89/C90 standard (ISO/IEC 9899:1990):

4.12.1 Components of time

localtimelocaltime_s (C11)	converts time since epoch to calendar time expressed as local time (function)
gmtimegmtime_s (C11)	converts time since epoch to calendar time expressed as Coordinated Universal Time (UTC) (function)

tm

Member objects

Notes

Example

References

See also