Last updated: Fri, 22 Aug 2008

mktime

(PHP 4, PHP 5)

mktime — Obtém um timestamp Unix para uma data

Descrição

int mktime ([ int $hora [, int $minuto [, int $second [, int $mes [, int $dia [, int $ano [, int $is_dst ]]]]]]] )

Retorna o timestamp Unix correspondente para os argumentos dados. Este timestamp é um longo inteiro contendo o número de segundos entre a Era Unix (January 1 1970 00:00:00 GMT) e o tempo especificado.

Argumentos podem ser omitidos da direita para esquerda; quaisquer argumentos assim omitidos serão definidos para o valor atual de acordo com a data e a hora local.

Parâmetros

hour: O número da hora.
minute: O número do minuto.
second: O número de segundos passados do minuto.
month: O número do mês.
day: O número do dia.
year: O número do ano. Pode conter dois ou quatro dígitos, com os valores entre 0-69 significando 2000-2069 e 70-100 para 1970-2000. Em sistemas aonde o time_t é um inteiro assinado de 32 bit, como é mais comum, o alcance do ano é algo entre 1901 e 2038. Entretanto, antes do PHP 5.1.0 esse range era limitado para 1970 até 2038 em alguns sistemas (ex. Windows).
is_dst: Este parâmetro pode ser definido para 1 se está durante o horário de verão (DST), 0 se não está, ou -1 (o padrão) se é desconhecido se o tempo está dentro do horário de verão ou não. Se é desconhecido, o PHP tenta compreender por si mesmo. Isto pode causar inesperado (mas não incorreto) resultados. As vezes é inválido se DST é habilitado no sistema em que o PHP está executando ou is_dst é definido para 1. Se DST é habilitado em e.g. 2:00, todo tempo entre 2:00 e 3:00 são inválidos e mktime() retorna um indefinido (normalmente negativo) valor. Alguns sistemas (e.g. Solaris 8) habilita DST na meia-noite então tempo 0:30 do dia quando DST está habilitado é avaliado como 23:30 do dia anterior.

Nota: No PHP 5.1.0, este parâmetro tornou-se obsoleto. Como resultado, o o novo recurso de manuseamento de timezone deve ser usado ao invés dele.

Valor Retornado

mktime() retorna o Unix timestamp dos argumentos dado. Se os argumentos são inválidos, a função retorna FALSE (antes do PHP 5.1 retornava -1).

Erros

Toda a chamada a uma função de data/hora irá gerar um se a zona da hora não for valida, e/ou uma mensagem E_STRICT se estiver usando a definição do sistema ou a variável de ambiente TZ. Veja também date_default_timezone_set()

Histórico

Versão	Descrição
3.0.10	Adicionado o parâmetro`is_dst`
5.1.0	O parâmetro `is_dst` tornou-se obsoleto. Fazendo a função retornar `FALSE` em erro, ao invés de -1. Reparada a função para aceitar o ano, mês e dia para ser todos passados como zero.
5.1.0	Agora emite `E_STRICT` e `E_NOTICE` em erros da zona de horário.

Exemplos

Exemplo #1 Exemplo da mktime()

mktime() é útil durante a aritmética e validação de data, enquanto ela calculará automaticamente o valor correto para a entrada fora do intervalo. Por exemplo, cada uma das seguintes linhas produzirá a string "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));
?>

Exemplo #2 Último dia do próximo mês

O último dia de um mês dado pode ser expressado como o dia "0" do mês seguinte, não o dia -1. Os dois exemplos seguintes produzirão a string "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);
?>

Notas

Cuidado

Antes do PHP 5.1.0, timestamp negativos não eram suportados em nenhuma versão conhecida do Windows e em alguns outros sistemas também. Portanto o intervalo válido de anos foi limitado para 1970 até 2038.

Veja Também

strftime

microtime

Last updated: Fri, 22 Aug 2008

add a note User Contributed Notes
mktime

ooogla at hotmail dot com
01-Sep-2008 07:56


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 11:34


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 06:58


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 02:58


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 11:31


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
17-Jul-2007 01:52


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 10:04


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 01:46


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 08:43


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 10:42


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 02:07


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 08:40


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
31-Mar-2005 03:48


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 12:50


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

joakim stai
28-Mar-2004 03:48


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 06:44


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
09-Dec-2003 01:49


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 06:06


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 02:42


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: Fri, 22 Aug 2008