Last updated: Sun, 25 Nov 2007

mktime

(PHP 4, PHP 5)

mktime — 取得一个日期的 Unix 时间戳

说明

int mktime ([ int $hour [, int $minute [, int $second [, int $month [, int $day [, int $year [, int $is_dst ]]]]]]] )

根据给出的参数返回 Unix 时间戳。时间戳是一个长整数，包含了从 Unix 纪元（January 1 1970 00:00:00 GMT）到给定时间的秒数。

参数可以从右向左省略，任何省略的参数会被设置成本地日期和时间的当前值。

参数

hour: 小时数。
minute: 分钟数。
second: 秒数（一分钟之内）。
month: 月份数。
day: 天数。
year: 年份数，可以是两位或四位数字，0-69 对应于 2000-2069，70-100 对应于 1970-2000。在如今系统中普遍把 time_t 作为一个 32 位有符号整数的情况下，year 的合法范围是 1901 到 2038 之间，不过此限制自 PHP 5.1.0 起已被克服了。
is_dst: 本参数可以设为 1，表示正处于夏时制时间（DST），0 表示不是夏时制，或者 -1（默认值）表示不知道是否是夏时制。如果未知，PHP 会尝试自己搞明白。这可能产生不可预知（但并非不正确）的结果。如果 PHP 运行的系统中启用了 DST 或者 is_dst 设为 1，某些时间是无效的。例如 DST 自 2:00 生效，则所有处于 2:00 到 3:00 之间的时间都无效，mktime() 会返回一个未定义（通常为负）的值。某些系统（例如 Solaris 8）的 DST 在午夜生效，则 DST 生效当天的 0:30 会被计算为前一天的 23:30。

Note: 自 PHP 5.1.0 起，本参数已被废弃。应该使用新的时区处理特性来替代。

返回值

mktime() 根据给出的参数返回 Unix 时间戳。如果参数非法，本函数返回 FALSE（在 PHP 5.1 之前返回 -1）。

更新日志

版本	说明
3.0.10	加入了 `is_dst` 参数
5.1.0	`is_dst` 参数被废弃。出错时函数返回 `FALSE` 而不再是 -1。修正了本函数可以接受年月日参数全为零。

范例

Example#1 mktime() 例子

mktime() 在做日期计算和验证方面很有用，它会自动计算超出范围的输入的正确值。例如下面例子中每一行都会产生字符串 "Jan-01-1998"。


<?php
echo date("M-d-Y", mktime(0, 0, 0, 12, 32, 1997));
echo date("M-d-Y", mktime(0, 0, 0, 13, 1, 1997));
echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 1998));
echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 98));
?>

Example#2 下个月的最后一天

任何给定月份的最后一天都可以被表示为下个月的第 "0" 天，而不是 -1 天。下面两个例子都会产生字符串 "The last day in Feb 2000 is: 29"。


<?php
$lastday = mktime(0, 0, 0, 3, 0, 2000);
echo strftime("Last day in Feb 2000 is: %d", $lastday);
$lastday = mktime(0, 0, 0, 4, -31, 2000);
echo strftime("Last day in Feb 2000 is: %d", $lastday);
?>

注释

Caution

在 PHP 5.1.0 之前，在任何已知 Windows 版本以及一些其它系统下不支持负的时间戳。因此年份的有效范围限制为 1970 到 2038。

参见

strftime

microtime

Last updated: Sun, 25 Nov 2007

add a note User Contributed Notes
mktime

Alan
18-Nov-2008 07:52


Do remember that, counter-intuitively enough, the arguments for month and day are inversed (or middle-endian). A common mistake for Europeans seems to be to feed the date arguments in the expected order (big endian or little endian).



It's clear to see where this weird order comes from (even with the date being big endian the order for all arguments would still be mixed - it's obviously based on the American date format with the time "prefixed" to allow an easier shorthand) and why this wasn't changed (passing the values in the wrong order produces a valid, though unexpected, result in most cases), but it continues to be a source of confusion for me whenever I come back to PHP from other languages or libraries.

Anonymous
14-Nov-2008 08:34


<?php


//example of functions to know if a date/time value is in summer hour or in winter hour





//====================


function getChgWinDate($dt){


 $y=substr($dt,0,4);


 for($i=31;$i>20;$i--){


  $ts=mktime(3,0,0,10,$i,$y);


  $dy=date('D',$ts);


  if($dy=='Sun') return($y.'/10/'.$i.' 03:00:00');


 }


}


//====================


function getChgSumDate($dt){


 $y=substr($dt,0,4);


 for($i=31;$i>20;$i--){


  $ts=mktime(2,0,0,10,$i,$y);


  $dy=date('D',$ts);


  if($dy=='Sun') return($y.'/03/'.$i.' 02:00:00');


 }


}


//====================


function isSummerDate($dt){


 $b1=getChgWinDate($dt);


 $b2=getChgSumDate($dt);


 if($dt>=$b2&&$dt<$b1) return(true);


 return(false);


}


//====================


function isWinterDate($dt){


 return(!isSummerDate($dt));


}





//====================


$dt = '2008/10/26 03:15:16';


if( isSummerDate($dt) ){


 echo $dt . " is summer hour in france";


}else{


 echo $dt . " is winter hour in france";


}


?>

thebloodyharry at gmail dot com
10-Nov-2008 06:04


here simple sample for timestamps.(using malaysia GMT 8)



$mkendtimep=mktime(date("H")+8, date("i"), date("s"), date("m"), date("d"), date("Y"));



$todaydate=date("(d/m/y) H:i:s", $mkendtimep);

if (date("l")=="Monday") { $mday=Monday; } else

    if (date("l")=="Tuesday") { $mday=Tuesday; } else

    if (date("l")=="Wednesday") { $mday=Wednesday; } else

    if (date("l")=="Thursday") { $mday=Thursday; } else

    if (date("l")=="Friday") { $mday=Friday; } else

    if (date("l")=="Saturday") { $mday=Saturday; } else

    if (date("l")=="Sunday"){  $mday=Sunday; } 



$realtime="$mday$todaydate (GMT +8)";



..hope it will help you out....

yan
10-Nov-2008 05:50


caculate days between two date



<?php

  // end date is 2008 Oct. 11 00:00:00

  $_endDate = mktime(0,0,0,11,10,2008);

  // begin date is 2007 May 31 13:26:26

  $_beginDate = mktime(13,26,26,05,31,2007);



  $timestamp_diff= $_endDate-$_beginDate +1 ;

  // how many days between those two date

  $days_diff = $timestamp_diff/86400;



?>

Maffu
29-Oct-2008 04:05


When calling mktime(), be sure that you use values without leading zeros.  The date comes out wrong in the following example:



$endts = mktime(12, 00, 00, 12, 08, 2008, 0);



(note the 08 instead of just 8)



C's scanf() has a format specification where leading 0's can indicate an octal value - perhaps this is related?

mark at markfiend dot com
15-Oct-2008 04:52


zola at zolaweb:



Your expression date('U', strtotime($mydate)) evaluates to strtotime($mydate). Converting to a UNIX timestamp is what strtotime() does.

ionut dot bodea at eydos dot ro
02-Oct-2008 08:29


Here is what I use to calculate age. It took me 30 minutes to write and it's quite accurate. What it has special is that it's calculating the number of days a year has (float number), by testing if a year is a leap one or not. This number is used to compute the age.





<?php


function get_age($date_start, $date_end) {


    $t_lived = get_timestamp($date_end) - get_timestamp($date_start);


    $seconds_one_year = get_days_per_year($date_start, $date_end) * 24 * 60 * 60;


    $age = array();


    $age['years_exact'] = $t_lived / $seconds_one_year;


    $age['years'] = floor($t_lived / $seconds_one_year);


    $seconds_remaining = $t_lived % $seconds_one_year;


    $age['days'] = round($seconds_remaining / (24 * 60 * 60));


    return $age;


}


function get_timestamp($date) {


    list($y, $m, $d) = explode('-', $date);


    return mktime(0, 0, 0, $m, $d, $y);


}


function get_days_per_year($date_start, $date_end) {


    list($y1) = explode('-', $date_start);


    list($y2) = explode('-', $date_end);


    $years_days = array();


    for($y = $y1; $y <= $y2; $y++) {


        $years_days[] = date('L', mktime(0, 0, 0, 1, 1, $y)) ? 366 : 365;


    }


    return round(array_sum($years_days) / count($years_days), 2);


}





$date_birth = '1979-10-12';


$date_now = date('Y-m-d');





$age = get_age($date_birth, $date_now);


echo '<pre>';


print_r($age);


echo '</pre>';


?>








It will display something like this:


Array


(


    [years_exact] => 28.972974329491


    [years] => 28


    [days] => 355


)

Anonymous
02-Oct-2008 05:28


Don't know about others, but this makes more sense to me:





<?php


function dateserial($year,$month,$day,$hour,$minute,$timezone = "UTC") {


    $orgTZ = date_default_timezone_get();


    date_default_timezone_set($timezone);


    $retval = mktime($hour,$minute,0,$month,$day,$year);


    date_default_timezone_set($orgTZ);


    return $retval;


}


?>





The order makes more sense and the timezone defaults to UTC unless otherwise specified. The fact that you have to set the timezone gives you more control and forces you to be aware of it.

zola at zolaweb dot com
27-Sep-2008 01:27


You can't use something along the lines of



$mydate = '2008-27-09 3:52:06';

$x = mktime(date("Y", $mydate), date("m", $mydate), date("d", $mydate),  date("H", $mydate), date("i", $mydate), date("s", $mydate));



because mktime will puke on the leading zeroes, you'll get "Notice: A non well formed numeric value encountered in ...."



There's no setting to get seconds without leading zeros, at least not yet, so you have to prepare your date string first.



You can explode your date as some examples have shown, and then either multiply each result by 1 to remove the leading zero, or trim them off, but even simpler is to convert to the unix epoch:



$convert_date = date('U', strtotime($mydate));



You can add or subtract time in the ordinary way



$convert_date = date('U', strtotime("+1 day", $mydate));



and then convert it back to your preferred dateformat without invoking mktime at all.



$mynewdate = date('Y-m-d H:i:s', $convert_date);

 

Hopefully this will be useful if you are trying to calculate from an already formatted date, such as one grabbed from a database or mail.

domi at lab-9 dot com
16-Sep-2008 12:27


[quote thomas_corthals at hotmail dot com]

It seems mktime() doesn't return negative timestamps on Linux systems with a version of glibc <= 2.3.3.

[/quote]



Negative timestamps are not supported in any known Windows environment. Therefore only valuations for year in range of [1970..2038] are allowed. Thus you cannot rely that php knows how to handle negative timestamps. If you have valuations with year out of [1970..2038] you may got to think of a alternative implementation using date() and parse variables for yourself OR (which would be much faster) a self-designed class that safely calculates dates out of range.

ooogla at hotmail dot com
01-Sep-2008 03:56


If you want to increment the day based on a variable when using a loop you can use this when you submit a form



1. Establish a start date and end date in two different variables



2. Get the number of days between a date



$ndays = (strtotime($_POST['edate']) - strtotime($_POST['sdate'])) / (60 * 60 * 24);



Then here is the string you slip in your loop



$nextday  = date('Y-m-d', mktime(0, 0, 0, date("m", strtotime($_POST['sdate']))  , date("d", strtotime($_POST['sdate']))+ $count, date("Y", strtotime($_POST['sdate']))));



$count is incremented by the loop.

thomas_corthals at hotmail dot com
13-May-2008 07:34


It seems mktime() doesn't return negative timestamps on Linux systems with a version of glibc <= 2.3.3.

joseph dot andrew dot hughes at gmail dot com
30-Jan-2008 12:58


Just a small thing to think about if you are only trying to pull the month out using mktime and date.  Make sure you place a 1 into day field.  Otherwise you will get incorrect dates when a month is followed by a month with less days when the day of the current month is higher then the max day of the month you are trying to find.. (Such as today being Jan 30th and trying to find the month Feb.)

PHPcoder at freemail dot ig3 dot net
06-Sep-2007 10:58


The maximum possible date accepted by mktime() and gmmktime() is dependent on the current location time zone.



For example, the 32-bit timestamp overflow occurs at 2038-01-19T03:14:08+0000Z.  But if you're in a UTC -0500 time zone (such as EST in North America), the maximum accepted time before overflow (for older PHP versions on Windows) is 2038-01-18T22:14:07-0500Z, regardless of whether you're passing it to mktime() or gmmktime().

Jonathan Woodard
31-Aug-2007 07:31


NB: one 'gotcha' with the implementation of mktime()'s parameters:



<?php

for( $i = 1 ;  $i <= 12 ; $i++ )

{

    echo "Month '$i' is: " . date( "F" , mktime( 0 , 0 , 0 , $i ) ) . "\n";

}

?>

Will output:

Month '1' is: January

Month '2' is: March

Month '3' is: March

Month '4' is: May

Month '5' is: May

Month '6' is: July

Month '7' is: July

Month '8' is: August

Month '9' is: October

Month '10' is: October

Month '11' is: December

Month '12' is: December

on the 31st day of every month.



Why? Because the 5th parameter "day" defaults to "right now," which will not work reliably for days after the 28th.



To make sure this doesn't happen, specify the first day of the month:

<?php

mktime( 0 , 0 , 0 , $i , 1 )

?>

rlz
16-Jul-2007 09:52


Finding out the number of days in a given month and year, accounting for leap years when February has more than 28 days.





<?php


function days_in_month($year, $month) {


    return( date( "t", mktime( 0, 0, 0, $month, 1, $year) ) );


}


?>





Hope it helps a soul out there.

mike at mike-griffiths dot co dot uk
11-Jul-2007 06:04


It may be useful to note that no E_WARNINGS or E_NOTICES are give if you specify a date <1901 or >2038 on systems where time_t is a 32bit signed integer.



If a date is specified outside of the allowed range you may get some unexpected results as no timestamp will be returned.

rga at merchantpal dot com
31-Mar-2007 09:46


You cannot simply subtract or add month VARs using mktime to obtain previous or next months as suggested in previous user comments (at least not with a DD > 28 anyway).



If the date is 03-31-2007, the following yeilds March as a previous month. Not what you wanted.



<?php

$dateMinusOneMonth = mktime(0, 0, 0, (3-1), 31,  2007 );

$lastmonth = date("n | F", $dateMinusOneMonth);

echo $lastmonth;    //---> 3 | March

?>



mktime correctly gives you back the 3rd of March if you subtract 1 month from March 31 (there are only 28 days in Feb 07).



If you are just looking to do month and year arithmetic using mktime, you can use general days like 1 or 28 to do stuff like this:



<?php

$d_daysinmonth = date('t', mktime(0,0,0,$myMonth,1,$myYear));     // how many days in month

$d_year = date('Y', mktime(0,0,0,$myMonth,1,$myYear));        // year

$d_isleapyear = date('L', mktime(0,0,0,$myMonth,1,$myYear));    // is YYYY a leapyear?



$d_firstdow = date('w', mktime(0,0,0,$myMonth,'1',$myYear));     // FIRST falls on what day of week (0-6)

$d_firstname = date('l', mktime(0,0,0,$myMonth,'1',$myYear));     // FIRST falls on what day of week Full Name



$d_month = date('n', mktime(0,0,0,$myMonth,28,$myYear));         // month of year (1-12)

$d_monthname = date('F', mktime(0,0,0,$myMonth,28,$myYear));         // Month Long name (July)

$d_month_previous = date('n', mktime(0,0,0,($myMonth-1),28,$myYear));         // PREVIOUS month of year (1-12)

$d_monthname_previous = date('F', mktime(0,0,0,($myMonth-1),28,$myYear));     // PREVIOUS Month Long name (July)

$d_month_next = date('n', mktime(0,0,0,($myMonth+1),28,$myYear));         // NEXT month of year (1-12)

$d_monthname_next = date('F', mktime(0,0,0,($myMonth+1),28,$myYear));         // NEXT Month Long name (July)

$d_year_previous = date('Y', mktime(0,0,0,$myMonth,28,($myYear-1)));        // PREVIOUS year

$d_year_next = date('Y', mktime(0,0,0,$myMonth,28,($myYear+1)));        // NEXT year



$d_weeksleft = (52 - $d_weekofyear);                     // how many weeks left in year

$d_daysinyear = $d_isleapyear ? 366 : 365;                // set correct days in year for leap years

$d_daysleft = ($d_daysinyear - $d_dayofyear);                // how many days left in year

?>

Stephen
08-Jan-2007 02:43


There are several warnings here about using mktime() to determine a date difference because of daylight savings time. However, nobody seems to have mentioned the other obvious problem, which is leap years.



Leap years mean that any effort to use mktime() and time() to determine the age (positive or negative) of some timestamp in years will be flawed. There are some years that are 366 days long, therefore you cannot say that there is a set number of seconds per year.



Timestamps are good for determining *real* time, which is not the same thing as *human calendar* time. The Gregorian calendar is only an approximation of real time, which is tweaked with daylight savings time and leap years to make it conform more to humans' expectations of how time should or ought to work. Timestamps are not tweaked and therefore are the only authoritative way of recording in computers a proper order of succession of events, but they cannot be integrated with a Gregorian system unless you take both leap years and DST into account. Otherwise, you may get the wrong number of years when you are approaching a value of exactly X years.



As for PHP, you could still use timestamps as a way of determining age if you took into account not only DST but also whether or not each year is a leap year and adjusted your calculations accordingly. However, this could become messy and inefficient. 



There is an alternative approach to calculating days given the day, month and year of the dates to be compared. Compare the years first, and then compare the month and day - if the month and day have already passed (or, if you like, if they match the current month and day), then add 1 to the total for the years. 



This solution works because it stays within the Gregorian system and doesn't venture into the world of timestamps.



Here is a good discussion of this issue:



http://forums.devshed.com/php-development-5/

need-to-get-the-age-between-dob-

and-today-29925.html?&highlight=age+leap



[the above link was too long; combine the three lines to get the URL]



There is also the issue of leap seconds, but this will only arise if you literally need to get the *exact* age in seconds. In that case, of course, you would also need to verify that your timestamps are exactly correct and are not delayed by script processing time, plus you would need to determine whether your system conforms to UTC, etc. I expect this will hardly be an issue for anybody using PHP, however if you are interested there is an article on this issue on Wikipedia:



http://en.wikipedia.org/wiki/Leap_second

jsebfranck
07-Nov-2006 04:42


There are several notes for mktime which use the number 86400 to differentiate two days. However this technique may pose a problem in case there is a day where the hour change between the two dates to compare.



Consequently, if you want the timestamp difference between the day where the hour change and the next day, it will not be equals to 86400 but either 82800 in case its the winter change of hour day or 90000 for the summer change of hour day.



For example in 2006 :



<?php

echo mktime(0,0,0,10,29,2006) - mktime(0,0,0,10,30,2006); // -90 000

?>

scratch_fury at yahoo dot com
24-Aug-2006 10:07


In response to the post by "nicky" on July 9, 2006:



Just so everyone's clear, if you have a date string formatted in a standard way, you'll probably want to go ahead and use PHP's built-in strtotime() function.  The advantage to using nicky's str2time() function seems to be that you can specify how the date string you're passing in is formatted, so you can deal with non-standard date strings.

carlo dot tafuro at poste dot it
08-May-2006 04:40


Negative timestamps give problem also using linux as guest operating system inside WMvare with Windows host operating system.

colin dot horne at gmail dot com
30-Mar-2005 10:48


If the month is greater than 12, it goes into the next year. If it is less than 1, it goes into the previous year. Generally, it behaves as you'd expect it to :-)



Examples:



<?php



// January 1, 2005

print date ("F j, Y", mktime (0,0,0,13,1,2004));



// December 1, 2003

print date ("F j, Y", mktime (0,0,0,0,1,2004));



// February 1, 2005

print date ("F j, Y", mktime (0,0,0,14,1,2004));



// November 1, 2003

print date ("F j, Y", mktime (0,0,0,-1,1,2004));



?>

Romain Sam
25-Mar-2005 07:50


Under Windows, mktime goes until 2038-01-19 (03:14:07 ...)

joakim stai
28-Mar-2004 10:48


As Nigel pointed out, you should be aware of DST (Daylight Savings Time) when using mktime(). Some systems will return a negative value if you use 0 as the hour, as it will simply skip from (for example) 23:59:59 to 01:00:00. Instead use 12 (noon) as the hour and you won't get a negative timestamp or a date in the 1960's.



This code will work with DST:

$today = mktime(12, 0, 0, date("m"), date("d"), date("Y"));

praas at NOSPAM dot ision dot nl
01-Feb-2004 12:44


Consider skipping months with mktime().



$nextmonth = date("M",mktime(0,0,0,date("n")+1,date("j"),date("Y")));



On any day in Januari you expect to get Feb, right? 

But on January 30th you'll get Mar. It will try Feb 30th, which doesn't exist, and skips another month. Therefore in this case present a day value that will certainly be legal in any month, like day "1".



This will give you next month on any day of the year:

$nextmonth = date("M",mktime(0,0,0,date("n")+1,1,date("Y")));

iain at seatofthepants dot net
08-Dec-2003 07:49


In the above example it should ne boted that if you try to calculate the command at midnight on the 28/04/2004 you will get an erroneous response. This has been driving me to distraction.



$myTime = mktime( 0, 0, 0, 3, 28, 2004);



Solution I found was to create the time at 3am well after the 2am daylight savings problem, viz:



$myTime = mktime( 3, 0, 0, 3, 28, 2004);



Not sure if this is documented anywhere.

trahma
20-Nov-2003 12:06


I think it is important to note that the timestamp returned is based upon the number of seconds from the epoch GMT, and then modified by the time zone settings on the server.



Thus...



mktime(0,0,0,1,1,1970) will not always return 0.  For example with the US eastern time zone (GMT-5) will return 18000 (5 hours past the epoch) and the same function with the time zone set to the US pacific time zone (GMT-8) will return 28800 (8 hours past the epoch).



In an instance where you want time zone independence, you should use the function gmmktime()

laurie at oneuponedown dot com
18-Nov-2003 08:42


With regard to Example 1 and using mktime to correct out-of-range input.





It should be noted that mktime will implement day light saving amends. Consider the following:





<?php


print(date("d/m/Y H:i:s",mktime(0,0,0,3,(27 + 1),2004)));


?>


OUTPUT "28/03/2004 02:00:00"





<?php


print(date("d/m/Y H:i:s",(mktime(0,0,0,3,27,2004) + (((1 * 24) * 60) * 60))));


?>


OUTPUT "28/03/2004 00:00:00"





Dependent on your requirements this may or may be desirable

add a note

strftime

microtime

Last updated: Sun, 25 Nov 2007