{{task}}

;Task: Choose popular date libraries used by your language and show the [[wp:Epoch_(reference_date)#Computing|epoch]] those libraries use.

A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scenes by the implementers), but text from (with links to) documentation is also acceptable where a demonstration is impossible/impractical.

For consistency's sake, show the date in UTC time where possible.

;Related task:

• [[Date format]]

ABAP

DATA: lv_date TYPE datum.

lv_date = 0.

WRITE: / lv_date.

{{out}}

00.00.0000

Simplified

cl_demo_output=>display( |Result: { CONV datum( 0 ) }| ).

{{out}}

00.00.0000

Ada

In Ada, time is a private type and is implementation defined, for instance, on 64 bit GNAT, time is represented internally as nanoseconds relative to Jan 1, 2150.

However, conversion from unix epoch seconds is also supported and shown below.

with Ada.Text_IO; use Ada.Text_IO;
with Ada.Calendar; use Ada.Calendar;
with Ada.Calendar.Formatting; use Ada.Calendar.Formatting;
with Ada.Calendar.Conversions; use Ada.Calendar.Conversions;
procedure ShowEpoch is
   etime : Time := To_Ada_Time (0);
begin
   Put_Line (Image (Date => etime));
end ShowEpoch;

{{out}}

1970-01-01 00:00:00

AWK

# syntax: GAWK -f SHOW_THE_EPOCH.AWK
# requires GNU Awk 4.0.1 or later
BEGIN {
    print(strftime("%Y-%m-%d %H:%M:%S",0,1))
    exit(0)
}

{{out}}

1970-01-01 00:00:00

BBC BASIC

{{works with|BBC BASIC for Windows}}

      INSTALL @lib$+"DATELIB"
      PRINT FN_date$(0, "dd-MMM-yyyy")

'''Output:'''

17-Nov-1858

C

#include <time.h>
#include <stdio.h>

int main() {
    time_t t = 0;
    printf("%s", asctime(gmtime(&t)));
    return 0;
}

{{out}}

Thu Jan  1 00:00:00 1970

Windows

FileTime, from the Win32 API, uses a different epoch. {{libheader|Win32}}

#include <windows.h>
#include <stdio.h>
#include <wchar.h>

int
main()
{
	FILETIME ft = {dwLowDateTime: 0, dwHighDateTime: 0};  /* Epoch */
	SYSTEMTIME st;
	wchar_t date[80], time[80];

	/*
	 * Convert FILETIME (which counts 100-nanosecond intervals since
	 * the epoch) to SYSTEMTIME (which has year, month, and so on).
	 *
	 * The time is in UTC, because we never call
	 * SystemTimeToTzSpecificLocalTime() to convert it to local time.
	 */
	FileTimeToSystemTime(&ft, &st);

	/*
	 * Format SYSTEMTIME as a string.
	 */
	if (GetDateFormatW(LOCALE_USER_DEFAULT, DATE_LONGDATE, &st, NULL,
	    date, sizeof date / sizeof date[0]) == 0 ||
	    GetTimeFormatW(LOCALE_USER_DEFAULT, 0, &st, NULL,
	    time, sizeof time / sizeof time[0]) == 0) {
		fwprintf(stderr, L"Error!\n");
		return 1;
	}

	wprintf(L"FileTime epoch is %ls, at %ls (UTC).\n", date, time);
	return 0;
}

{{out}}

FileTime epoch is Monday, January 01, 1601, at 12:00:00 AM (UTC).

C#

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine(new DateTime());
    }
}

{{out}}

1-1-0001 0:00:00

C++

{{works with|C++11}} {{works with|gcc|4.5.3}} Doesn't work with MSVC 10 SP1

#include <iostream>
#include <chrono>
#include <ctime>
int main()
{
    std::chrono::system_clock::time_point epoch;
    std::time_t t = std::chrono::system_clock::to_time_t(epoch);
    std::cout << std::asctime(std::gmtime(&t)) << '\n';
    return 0;
}

{{out}}

Thu Jan  1 00:00:00 1970

{{libheader|boost}}

#include <iostream>
#include <boost/date_time.hpp>
int main()
{
    std::cout << boost::posix_time::ptime( boost::posix_time::min_date_time ) << '\n';
    return 0;
}

{{out}}

1400-Jan-01 00:00:00

Clojure

(println (java.util.Date. 0))

Output (since Clojure 1.5) #inst "1970-01-01T00:00:00.000-00:00"

## COBOL


```cobol
       IDENTIFICATION DIVISION.
       PROGRAM-ID. epoch.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  epoch-date.
           03  year                PIC 9(4).
           03  month               PIC 99.
           03  dday                PIC 99.

       PROCEDURE DIVISION.
           MOVE FUNCTION DATE-OF-INTEGER(1) TO epoch-date

           DISPLAY year "-" month "-" dday

           GOBACK
           .

{{out}}

1601-01-01

CoffeeScript

console.log new Date(0).toISOString()

{{out}}

Thu, 01 Jan 1970 00:00:00 GMT

Common Lisp

(multiple-value-bind (second minute hour day month year) (decode-universal-time 0 0)
 	  (format t "~4,'0D-~2,'0D-~2,'0D ~2,'0D:~2,'0D:~2,'0D" year month day hour minute second))

{{out}}

1900-01-01 00:00:00

D

The Date struct of the standard library module "std.datetime" represents a date in the Proleptic Gregorian Calendar ranging from 32,768 B.C. to 32,767 A.D.

Dart

main() {
  print(new Date.fromEpoch(0,new TimeZone.utc()));
}

{{out}}

1970-01-01 00:00:00.000Z

Delphi

program ShowEpoch;

{$APPTYPE CONSOLE}

uses SysUtils;

begin
  Writeln(FormatDateTime('yyyy-mm-dd hh:nn:ss.zzz', 0));
end.

{{out}}

1899-12-30 00:00:00.000

Erlang

Erlang uses 2 3-tuples for time and date manipulation. It is possible to get the current values from the operating system. It is also possible to transform these values to/from gregorian seconds. Those are seconds since the date and time interpreted with the Gregorian calendar extended back to year 0. Perhaps the epoch is the date and time at gregorian seconds 0?

2> calendar:universal_time().
{{2013,9,13},{8,3,16}}
3> calendar:datetime_to_gregorian_seconds(calendar:universal_time()).
63546278932
4> calendar:gregorian_seconds_to_datetime(63546278932).
{{2013,9,13},{8,8,52}}
11> calendar:gregorian_seconds_to_datetime(0).
{{0,1,1},{0,0,0}}

=={{header|F_Sharp|F#}}==

printfn "%s" ((new System.DateTime()).ToString("u"))

{{out}}

0001-01-01 00:00:00Z

Factor

IN: USE: calendar calendar.format
IN: 0 micros>timestamp timestamp>ymdhms .
"1970-01-01 00:00:00"

Forth

{{works with|4tH|3.61.3}}

include lib/longjday.4th
0 posix>jday .longjday  cr

{{out}}

Thursday, January 1, 1970

Fortran

Fortran offers no standard time-type variables nor library routines whereby a timestamp value is given as say some number of seconds from a particular epoch such as the start of the first of January 1970, etc. Individual systems and individual programmers have their own schemes, for instance counting the first of January 1900 as day one - whereby day zero is a Sunday. F90 introduced a complex subroutine with optional named parameters as well as an eight-element integer array whereby CALL DATE_AND_TIME(IVALS) when invoked returns the computer's current date and time as a four-digit year in IVAL(1), the month of the year in IVAL(2), the day of the month in IVAL(3), the difference in minutes with respect to UTC (ex-GMT) time in IVAL(4), and so on down to milliseconds in IVAL(8). One could then argue that the base epoch, day one for instance, is the first of January year 1 and discuss the proleptic Gregorian calendar.

FreeBASIC

FreeBASIC's built-in date/time library is based on an object called a 'date serial' which uses an epoch of 0:00 AM on December 30, 1899. This is the same epoch used internally for date/time purposes by COM, Visual Basic, Delphi, Excel, LibreOffice Calc and Google Sheets amongst others.

A DateSerial is a double precision floating point number whose integer part represents the number of days after (or in the case of a negative value, the number of days before) the epoch and the fractional part represents the time on that day. As such, the date/time range covered is virtually unlimited.

Date/time values in FB are always based on the current regional settings and so, if values are needed for other time-zones (or UTC), the appropriate adjustments must be made.

' FB 1.05.0 Win64

#Include "vbcompat.bi"

' The first argument to the Format function is a date serial
' and so the first statement below displays the epoch.

Dim f As String = "mmmm d, yyyy hh:mm:ss"
Print Format( 0 , f)      '' epoch
Print Format( 0.5, f)     '' noon on the same day
Print Format(-0.5, f)     '' noon on the previous day
Print Format(1000000, f)  '' one million days after the epoch
Print Format(-80000, f)   '' eighty thousand days before the epoch
Print
Print "Press any key to quit"
Sleep

{{out}}

December 30, 1899 00:00:00
December 30, 1899 12:00:00
December 29, 1899 12:00:00
November 26, 4637 00:00:00
December 17, 1680 00:00:00

FutureBasic

include "ConsoleWindow"

print date$
print date$("d MMM yyyy")
print date$("EEE, MMM d, yyyy")
print date$("MMMM d, yyyy ")
print date$("MMMM d, yyyy G")
print "This is day ";date$("D");" of the year"
print
print time$
print time$("hh:mm:ss")
print time$("h:mm a")
print time$("h:mm a zzz")
print
print time$("h:mm a ZZZZ "); date$("MMMM d, yyyy G")

Output:

09/03/16
3 Sep 2016
Sat, Sep 3, 2016
September 3, 2016
September 3, 2016 AD
This is day 247 of the year

23:44:12
11:44:12
11:44 PM
11:44 PM EDT

11:44 PM GMT-04:00 September 3, 2016 AD

Go

package main
import ("fmt"; "time")

func main() {
    fmt.Println(time.Time{})
}

{{out}} This is UNIX format. The 1 on the end is the full year, not two or four digit year.

Mon Jan  1 00:00:00 +0000 UTC 1

Groovy

Groovy uses the UNIX epoch.

def date = new Date(0)
def format = new java.text.SimpleDateFormat('yyyy-MM-dd\'T\'HH:mm:ss.SSSZ')
format.timeZone = TimeZone.getTimeZone('UTC')
println (format.format(date))

{{out}}

1970-01-01T00:00:00.000+0000

Haskell

Old time library

The ClockTime type is abstract in Haskell 98, but is defined in GHC. {{works with|GHC}}

import System.Time

main = putStrLn $ calendarTimeToString $ toUTCTime $ TOD 0 0

{{out}}

Thu Jan  1 00:00:00 UTC 1970

New time library

{{works with|GHC}}

import Data.Time

main = print $ UTCTime (ModifiedJulianDay 0) 0

{{out}}

1858-11-17 00:00:00 UTC

=={{header|Icon}} and {{header|Unicon}}== Date and Time can be accessed via a number of keywords and functions

• The following are available in both Icon and Unicon ** &clock, &date, &dateline, and &time deal with current times and dates
• The following are specific to Unicon ** &now provides the number of seconds since the epoch, Jan 1, 1970 00:00:00 ** ctime(integer) takes the number of seconds since the epoch and returns the date and time as a string in the local timezone ** gtime(integer) takes the number of seconds since the epoch and returns the date and time as a string in UTC ** gettimeofday() returns a record with the current time since the epoch in seconds and microseconds {{libheader|Icon Programming Library}}
• [http://www.cs.arizona.edu/icon/library/src/procs/datetime.icn datetime routines] use a global variable 'DateBaseYear' which defaults to Jan 1, 1970 00:00:00 but can be set if desired.
• The example below uses only a couple of the datetime procedures

link printf,datetime

procedure main()
  # Unicon
  now := gettimeofday().sec
  if now = &now then printf("&now and gettimeofday().sec are equal\n")
  printf("Now (UTC) %s, (local) %s\n",gtime(now),ctime(now))
  printf("Epoch %s\n",gtime(0))
  # Icon and Unicon
  now := DateToSec(&date) + ClockToSec(&clock)
  printf("Now is also %s and %s\n",SecToDate(now),SecToDateLine(now))
end

{{out|Sample Output}}

&now and gettimeofday().sec are equal
Now (UTC) Tue Aug 09 10:43:23 2011, (local) Tue Aug 09 06:43:23 2011
Epoch Thu Jan 01 00:00:00 1970
Now is also 2011/08/09 and Tuesday, August 9, 2011  6:43 am

J

J does not have an epoch. J's native representation of date and time is a six element list: year, month, day, hour, minute, second. For example:

   6!:0''
2011 8 8 20 25 44.725

(August 8, 2011, 8:25:44 pm)

That said, the 'dates' library does have an epoch:

   require'dates'
   todate 0
1800 1 1

Java

DateFormat is needed to set the timezone. Printing date alone would show this date in the timezone/locale of the machine that the program is running on. The epoch used in java.util.Date (as well as java.sql.Date, which can be subbed into this example) is actually in GMT, but there isn't a significant difference between that and UTC for lots of applications ([http://download.oracle.com/javase/7/docs/api/java/util/Date.html#getTime() documentation for java.util.Date]).

import java.text.DateFormat;
import java.util.Date;
import java.util.TimeZone;

public class DateTest{
    public static void main(String[] args) {
        Date date = new Date(0);
        DateFormat format = DateFormat.getDateTimeInstance();
        format.setTimeZone(TimeZone.getTimeZone("UTC"));
        System.out.println(format.format(date));
    }
}

{{out}}

Jan 1, 1970 12:00:00 AM

On my PC I see

01.01.1970 00:00:00

JavaScript

document.write(new Date(0).toUTCString());

{{out}}

Thu, 01 Jan 1970 00:00:00 GMT

jq

0 | todate

{{out}}

"1970-01-01T00:00:00Z"

Julia

{{works with|Julia|0.6}}

using Base.Dates
println("Time zero (the epoch) is $(unix2datetime(0)).")

{{out}}

Time zero (the epoch) is 1970-01-01T00:00:00.

Kotlin

{{trans|Java}}

// version 1.1.2

import java.util.Date
import java.util.TimeZone
import java.text.DateFormat

fun main( args: Array<String>) {
    val epoch = Date(0)
    val format = DateFormat.getDateTimeInstance()
    format.timeZone = TimeZone.getTimeZone("UTC")
    println(format.format(epoch))
}

{{out}}

Jan 1, 1970 12:00:00 AM

Lasso

date(0.00)
date(0)

{{out}}

1969-12-31 19:00:00
1969-12-31 19:00:00

Limbo

implement Epoch;

include "sys.m"; sys: Sys;
include "draw.m";
include "daytime.m"; daytime: Daytime;
	Tm: import daytime;

Epoch: module {
	init: fn(nil: ref Draw->Context, nil: list of string);
};

init(nil: ref Draw->Context, nil: list of string)
{
	sys = load Sys Sys->PATH;
	daytime = load Daytime Daytime->PATH;
	sys->print("%s\n", daytime->text(daytime->gmt(0)));
}

Of course, this could also be done by mangling the namespace and forging the current date, locking it to the epoch:

implement Epoch;

include "sys.m"; sys: Sys;
include "draw.m";
include "daytime.m"; daytime: Daytime;
	Tm: import daytime;

Epoch: module {
	init: fn(nil: ref Draw->Context, nil: list of string);
};

init(nil: ref Draw->Context, nil: list of string)
{
	sys = load Sys Sys->PATH;
	daytime = load Daytime Daytime->PATH;

	# Create a file containing a zero:
	fd := sys->open("/tmp/0", Sys->OWRITE);
	if(fd == nil) {
		sys->fprint(sys->fildes(2), "Couldn't open /tmp/0 for writing: %r\n");
		raise "fail:errors";
	}
	sys->fprint(fd, "0");
	fd = nil; # Files with no references are closed immediately.

	# Fork the namespace so as not to disturb the parent
	# process's concept of time:
	sys->pctl(Sys->FORKNS, nil);
	# Bind that file over /dev/time:
	sys->bind("/tmp/0", "/dev/time", Sys->MREPL);

	# Print the "current" date, now the epoch:
	sys->print("%s\n", daytime->text(daytime->gmt(daytime->now())));
}

{{out}}

Thu Jan 01 00:00:00 GMT 1970

Lingo

Lingo's date object is not based on an epoch, but instead on runtime date calculations. A new date object is created by specifying "year, month, day", based on gregorian calendar. In arithmetic context, date objects are casted to "days" (AD), not to seconds or milliseconds (see below).

now = the systemDate
put now
-- date( 2018, 3, 21 )

babylonianDate = date(-1800,1,1)

-- print approx. year difference between "babylonianDate" and now
put (now-babylonianDate)/365.2425
-- 3818.1355

LiveCode

LiveCode uses midnight, January 1, 1970 as the start of the eon

put 0 into somedate
convert somedate to internet date
put somedate

-- output GMT (localised)
-- Thu, 1 Jan 1970 10:00:00 +1000

LotusScript

Uses LotusScript to calculate difference between current time and epoch start date. This example: a button which prints the result. Of course, change the timeStamp variable to whatever suits your need.

Sub Click(Source As Button)
  'Create timestamp as of now
  Dim timeStamp As NotesDateTime
  Set timeStamp = New NotesDateTime ( Now )

  'Assign epoch start time to variable
  Dim epochTime As NotesDateTime
  Set epochTime = New NotesDateTime ( "01/01/1970 00:00:00 AM GMT" )  ''' These two commands only to get epoch time.

  'Calculate time difference between both dates
  Dim epochSeconds As Long
  epochSeconds = timeStamp.TimeDifference ( epochTime )

  'Print result
  Print epochSeconds

End Sub

Output:

1445093823

Lua

print(os.date("%c", 0))

{{out}}

Thu Jan  1 00:00:00 1970

Mathematica

DateString[0]

->Mon 1 Jan 1900 00:00:00

=={{header|MATLAB}} / {{header|Octave}}== Matlab and Octave store date/time number in a floating point number counting the days.

d = [0,1,2,3.5,-3.5,1000*365,1000*366,now+[-1,0,1]];
for k=1:length(d)
    printf('day %f\t%s\n',d(k),datestr(d(k),0))
    disp(datevec(d(k)))
end;

{{out}}

day 0.000000	31-Dec--001 00:00:00
   -1   12   31    0    0    0
day 1.000000	01-Jan-0000 00:00:00
   0   1   1   0   0   0
day 2.000000	02-Jan-0000 00:00:00
   0   1   2   0   0   0
day 3.500000	03-Jan-0000 12:00:00
    0    1    3   12    0    0
day -3.500000	27-Dec--001 12:00:00
   -1   12   27   12    0    0
day 365000.000000	02-May-0999 00:00:00
   999     5     2     0     0     0
day 366000.000000	27-Jan-1002 00:00:00
   1002      1     27      0      0      0
day 734908.972013	09-Feb-2012 23:19:41
   2012.0000      2.0000      9.0000     23.0000     19.0000     41.9633
day 734909.972013	10-Feb-2012 23:19:41
   2012.0000      2.0000     10.0000     23.0000     19.0000     41.9633
day 734910.972013	11-Feb-2012 23:19:41
   2012.0000      2.0000     11.0000     23.0000     19.0000     41.9633

Which is to say, day one is the first of January, year zero - except that there is no year zero: one BC is followed by one AD (or, 1 BCE and 1 CE) and the Gregorian calendar scheme wasn't in use then either.

Maxima

timedate(0);
"1900-01-01 10:00:00+10:00"

NetRexx

{{trans|Java}}

/* NetRexx */
options replace format comments java crossref symbols nobinary

import java.text.DateFormat

edate = Date(0)
zulu  = DateFormat.getDateTimeInstance()
zulu.setTimeZone(TimeZone.getTimeZone('UTC'))
say zulu.format(edate)
return

'''Output:'''

Jan 1, 1970 12:00:00 AM

NewLISP

(date 0)
->"Thu Jan 01 01:00:00 1970"

Nim

import times

echo getGMTime(fromSeconds(0))

Output:

Thu Jan  1 00:00:00 1970

=={{header|Objective-C}}==

int main(int argc, const char *argv[]) {
  @autoreleasepool {

    NSDate *t = [NSDate dateWithTimeIntervalSinceReferenceDate:0];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss ZZ"];
    NSLog(@"%@", [dateFormatter stringFromDate:t]);

  }
  return 0;
}

{{out|Log}}

2001-01-01 00:00:00 +0000

OCaml

open Unix

let months = [| "January"; "February"; "March"; "April"; "May"; "June";
      "July"; "August"; "September"; "October"; "November"; "December" |]

let () =
  let t = Unix.gmtime 0.0 in
  Printf.printf "%s %d, %d\n" months.(t.tm_mon) t.tm_mday (1900 + t.tm_year)

{{out|Execution}}

$ ocaml unix.cma epoch.ml
January 1, 1970

Oforth

import: date

0 asDateUTC println

{{out}}

1970-01-01 00:00:00,000

PARI/GP

GP has no built-in date or time system.

system("date -ur 0")

PARI, as usual, has access to the same resources as [[#C|C]].

Pascal

This works with [[Free_Pascal| Free Pascal]]:

Program ShowEpoch;

uses
  SysUtils;

begin
  Writeln(FormatDateTime('yyyy-mm-dd hh:nn:ss.zzz', Now));
  Writeln(FormatDateTime('yyyy-mm-dd hh:nn:ss.zzz', 0));
end.

{{out}}

:> ./SelfDescribingNumber
2011-12-13 00:57:41.378
1899-12-30 00:00:00.000

Perl

print scalar gmtime 0, "\n";

{{out}}

Thu Jan  1 00:00:00 1970

Perl 6

say DateTime.new(0)

{{out}}

1970-01-01T00:00:00Z

Phix

The standard Phix file builtins/datetime.e does not use an epoch, but instead expects absolute values, eg Jan 1st 1970 is {1970,1,1,...}. I suppose the closest we can get is:

constant d0 = {0,1,1,0,0,0,1,1}
include builtins\timedate.e
?format_timedate(d0,"YYYY-MM-DD")
?format_timedate(d0,"Dddd, Mmmm d, YYYY")

"0000-01-01"
"Sunday, January 1, 0000"

Note that zeroes in DT_MONTH/DT_DAY/DT_DOW/DT_DOY will give it jip.

It only says Sunday because I told it to, plus day_of_week() is meaningless/wrong pre 1752, and blatently broken on 1st Jan 0AD.

PHP

<?php
echo gmdate('r', 0), "\n";
?>

{{out}}

Thu, 01 Jan 1970 00:00:00 +0000

PicoLisp

The 'date' function in PicoLisp returns a day number, starting first of March of the year zero. Calculated according to the gregorian calendar (despite that that calendar wasn't used in 0 AD yet).

: (date 1)
-> (0 3 1)  # Year zero, March 1st

PL/I

*process source attributes xref;
 epoch: Proc Options(main);
 /*********************************************************************
 * 20.08.2013 Walter Pachl  shows that PL/I uses 15 Oct 1582 as epoch
 * DAYS returns a FIXED BINARY(31,0) value which is the number of days
 * (in Lilian format) corresponding to the date d.
 *********************************************************************/
 Dcl d Char(17);
 Put Edit(datetime(),days(datetime()))
         (Skip,a,f(15));
 d='15821015000000000';
 Put Edit(d         ,days(d))
         (Skip,a,f(15));
 d='15821014000000000';
 Put Edit(d         ,days(d))
         (Skip,a,f(15));
 End;

Result:

20130820072642956         157365
15821015000000000              1
15821014000000000
IBM0512I  ONCODE=2112  X in SECS(X,Y) or DAYS(X,Y) was outside the
          supported range.
   At offset +00000283 in procedure with entry EPOCH

PowerShell

PowerShell uses .NET's DateTime structure and an integer can simply be casted appropriately:

[datetime] 0

{{out}}

Monday, January 01, 0001 12:00:00 AM

Three Alternates

Get-Date always returns its '''Kind''' property as Local:

Get-Date -Year 1 -Month 1 -Day 1 -Hour 0 -Minute 0 -Second 0 -Millisecond 0

{{Out}}

Monday, January 01, 0001 12:00:00 AM

This approach returns its '''Kind''' property as Unspecified:

New-Object -TypeName System.DateTime

{{Out}}

Monday, January 01, 0001 12:00:00 AM

Here you could describe the epoch date's '''Kind''' property as being Utc. Formatting the output as a list for demonstration:

New-Object -TypeName System.DateTime -ArgumentList 1, 1, 1, 0, 0, 0, ([DateTimeKind]::Utc) | Format-List

{{Out}}

Date        : 1/1/0001 12:00:00 AM
Day         : 1
DayOfWeek   : Monday
DayOfYear   : 1
Hour        : 0
Kind        : Utc
Millisecond : 0
Minute      : 0
Month       : 1
Second      : 0
Ticks       : 0
TimeOfDay   : 00:00:00
Year        : 1
DateTime    : Monday, January 01, 0001 12:00:00 AM

PureBasic

If OpenConsole()
  PrintN(FormatDate("Y = %yyyy  M = %mm  D = %dd, %hh:%ii:%ss", 0))

  Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
  CloseConsole()
EndIf

{{out}}

Y = 1970  M = 01  D = 01, 00:00:00

Python

 import time
>>> time.asctime(time.gmtime(0))
'Thu Jan  1 00:00:00 1970'
>>>

R

 epoch <- 0
> class(epoch) <- class(Sys.time())
> format(epoch, "%Y-%m-%d %H:%M:%S %Z")
[1] "1970-01-01 00:00:00 UTC"

Racket

#lang racket
(require racket/date)
(date->string (seconds->date 0 #f))

Output:

"Thursday, January 1st, 1970"

REXX

The epoch for the REXX language BIF (Built-In Function) '''DATE''' is: January 1st, year 1.

/*REXX program displays the number of days since the epoch for the DATE function (BIF). */

say '     today is: '  date()                    /*today's is format:     mm MON YYYY   */

days=date('Basedate')                            /*only the first char of option is used*/
say right(days, 40)         " days since the REXX base date of January 1st, year 1"

say ' and today is: '  date(, days, "B")         /*it should still be today (µSec later)*/
                    /*   ↑                ┌───◄─── This BIF (Built-In Function) is only */
                    /*   └─────────◄──────┘        for  newer  versions of  REXX  that  */
                    /*                             support the  2nd and 3rd  arguments. */

{{output|out}}

     today is:   3 Aug 2012
                                   734717 days since the REXX base date of January 1st, year 1
 and today is:   3 Aug 2012

Ring

load "guilib.ring"

New qApp {
         win1 = new qMainWindow() {
                setwindowtitle("Using QDateEdit")
                setGeometry(100,100,250,100)
                oDate = new qdateedit(win1) {
                        setGeometry(20,40,220,30)
	                oDate.minimumDate()
                }
                show()
                }
                exec()
                }

Output: [[File:CalmoSoftShowEpoch.jpg]]

Ruby

irb(main):001:0> Time.at(0).utc
=> 1970-01-01 00:00:00 UTC

Rust

extern crate time;

use time::{at_utc, Timespec};

fn main() {
    let epoch = at_utc(Timespec::new(0, 0));
    println!("{}", epoch.asctime());
}

{{out}}

Thu Jan  1 00:00:00 1970

Run BASIC

eDate$ = date$("01/01/0001")
cDate$ = date$(0) ' 01/01/1901
sDate$ = date$("01/01/1970")

Scala

import java.util.{Date, TimeZone, Locale}
import java.text.DateFormat

val df=DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, Locale.ENGLISH)
df.setTimeZone(TimeZone.getTimeZone("UTC"))
println(df.format(new Date(0)))

{{out}}

January 1, 1970 12:00:00 AM UTC

Seed7

The Seed7 library [http://seed7.sourceforge.net/libraries/time.htm time.s7i] defines the type [http://seed7.sourceforge.net/manual/types.htm#time time], which describes times and dates. For dates the proleptic Gregorian calendar is used (which assumes that the Gregorian calendar was even in effect at dates preceding its official introduction). This convention is used according to ISO 8601, which also defines that positive and negative years exist and that the year preceding 1 is 0. Therefore the epoch is the beginning of the year 0.

$ include "seed7_05.s7i";
  include "time.s7i";

const proc: main is func
  begin
    writeln(time.value);
  end func;

{{out}}

0000-01-01 00:00:00 UTC

Sidef

say Time.new(0).gmtime.ctime;

{{out}}

Thu Jan  1 00:00:00 1970

Standard ML

- Date.toString (Date.fromTimeUniv Time.zeroTime);
val it = "Thu Jan  1 00:00:00 1970" : string

Stata

. di %td 0
01jan1960
. di %tc 0
01jan1960 00:00:00

Tcl

% clock format 0 -gmt 1
Thu Jan 01 00:00:00 GMT 1970

TUSCRIPT

$$ MODE TUSCRIPT
- epoch
number=1
dayofweeknr=DATE (date,day,month,year,number)
epoch=JOIN(year,"-",month,day)
PRINT "epoch: ", epoch," (daynumber ",number,")"
- today's daynumber
dayofweeknr=DATE (today,day,month,year,number)
date=JOIN (year,"-",month,day)
PRINT "today's date: ", date," (daynumber ", number,")"

{{out}}

epoch: 1-1-1 (daynumber 1)
today's date: 2011-12-14 (daynumber 734487)

UNIX Shell

The nonstandard option date -r takes seconds from the epoch, and prints date and time. See [http://www.openbsd.org/cgi-bin/man.cgi?query=date&apropos=0&sektion=1&manpath=OpenBSD+Current&arch=i386&format=html date(1) manual]. {{works with|OpenBSD}}

$ date -ur 0
Thu Jan  1 00:00:00 UTC 1970

On systems with GNU date, you can do

$ TZ=UTC  date --date "$(date +%s) seconds ago"
Thu Jan  1 00:00:00 UTC 1970

Visual Basic

Sub Main()
    Debug.Print Format(0, "dd mmm yyyy hh:mm")
End Sub

{{out|Output (in debug window)}} 30 Dec 1899 00:00

zkl

Using the method tickToTock(time_t,useLocalTime) on Linux. tickToTock converts a time_t (seconds since the epoch) to "human" time. False means use UTC (vs local time, the default).

zkl: Time.Clock.tickToTock(0,False)
L(1970,1,1,0,0,0) // y,m,d, h,m,s

{{omit from|AutoHotkey}} {{omit from|GUISS}} {{omit from|Locomotive Basic}} {{omit from|ZX Spectrum Basic}}