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std::tm(3)		      C++ Standard Libary		    std::tm(3)

NAME
       std::tm - std::tm

Synopsis
	  Defined in header <ctime>
	  struct tm;

	  Structure holding a calendar date and	time broken down into its com-
       ponents.

Member objects
		       seconds after the minute
		       [0, 61]
	  int tm_sec   (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)
		       Daylight	Saving Time flag. The value is positive	if DST
       is in effect,
	  int  tm_isdst	 zero  if not and negative if no information is	avail-
       able.
		       (public member object)

Notes
	  The Standard mandates	only the presence of the  aforementioned  mem-
       bers in some order.
	  The implementations usually add more data members to this structure.

	   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).

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'

	    std::cout << "sizeof(std::tm) = " << sizeof(std::tm) << '\n'
		      << "sum of sizes of standard members = "
		      << sizeof(tm.tm_sec) +
			 sizeof(tm.tm_min) +
			 sizeof(tm.tm_hour) +
			 sizeof(tm.tm_mday) +
			 sizeof(tm.tm_mon) +
			 sizeof(tm.tm_year) +
			 sizeof(tm.tm_wday) +
			 sizeof(tm.tm_yday) +
			 sizeof(tm.tm_isdst) <<	'\n';
	}

Possible output:
	Sat Jan	 1 00:00:00 2022
	sizeof(std::tm)	= 56
	sum of sizes of	standard members = 36

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

http://cppreference.com		  2024.06.10			    std::tm(3)

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<https://man.freebsd.org/cgi/man.cgi?query=std::tm&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>

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