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(PHP 4, PHP 5)
mktime — Gibt den Unix-Timestamp/Zeitstempel für ein Datum zurück
Gibt den Unix-Timestamp entsprechend der gegebenen Argumente zurück. Dieser Timestamp ist ein Long Integer, der die Anzahl der Sekunden zwischen der Unix-Epoche (01. Januar 1970 00:00:00 GMT) und dem angegebenen Zeitpunkt enthält.
Einzelne Argumente können von rechts nach links weggelassen werden. Sie werden dann mit den Werten der lokalen Systemzeit bzw. des lokalen Systemdatums ersetzt.
Hinweis:
Seit PHP 5.1 wirft mktime() eine E_STRICT-Notice, wenn die Funktion ohne Argumente aufgerufen wird. Verwenden Sie in diesem Fall stattdessen die time()-Funktion.
Die Stunde.
Die Minute.
Die Anzahl der Sekunden nach der Minute.
Der Monat.
Der Tag.
Die Jahreszahl, die zwei- oder vierstellig angegeben werden kann. Werte von 0 bis 69 werden auf 2000-2069 gemappt, Werte von 70 bis 100 auf 1970-2000. Auf Systemen, auf denen time_t ein 32-Bit Signed Integer ist (das sind die meisten der heutigen Systeme), beginnt der gültige Wertebereich für year bei 1901 und endet bei 2038. Allerdings begrenzen PHP-Versionen vor 5.1.0 den Bereich auf einigen Systemen (z.B. Windows) auf 1970-2038.
is_dst kann bei Sommerzeit (DST) auf 1 gesetzt werden, der Wert 0 steht für Winter-/Normalzeit und -1 (Standardwert) heißt, dass unbekannt ist, ob gerade Sommer- oder Winterzeit herrscht. Sofern unbekannt, versucht PHP, dies selbst herauszufinden. Das kann zu unerwarteten (aber dennoch korrekten) Ergebnissen führen. Einige Zeitangaben sind ungültig, wenn die automatische Zeitumstellung auf dem System aktiviert ist, auf dem PHP läuft, oder auf dem der Parameter is_dst den Wert 1 hat. Wenn die Sommerzeit (DST) z.B. um 02:00 Uhr aktiviert wird, sind alle Zeitangaben zwischen 02:00 Uhr und 03:00 Uhr ungültig und mktime() gibt einen undefinierten (meist negativen) Wert zurück. Einige Betriebssyteme (z.B. Solaris 8) nehmen die Zeitumstellung um Mitternacht vor, so dass die Zeitangabe 0:30 als 23:30 des vorherigen Tages interpretiert wird.
Hinweis:
Seit PHP 5.1.0 gilt dieses Parameter als veraltet und wird nicht mehr zur Verwendung empfohlen. Verwenden Sie daher die neuen Features zum Handling von Zeitzonen.
mktime() gibt den zu den übergebenen Argumenten passenden Unix-Timestamp zurück. Wenn die Argumente ungültig sind, gibt die Funktion FALSE zurück (vor PHP 5.1 wurde dann -1 zurückgegeben).
Jeder Aufruf der Datums- und Zeitfunktionen generiert eine E_NOTICE-Warnung, wenn die Zeitzone ungültig ist und eine E_STRICT-Nachricht oder eine E_WARNING-Warnung, wenn die Systemeinstellung oder die TZ-Umgebungsvariable genutzt wird. Siehe auch date_default_timezone_set()
| Version | Beschreibung |
|---|---|
| 5.3.0 | mktime() wirft nun eine E_DEPRECATED-Notice, wenn der is_dst verwendet wird. |
| 5.1.0 | Der Parameter is_dst wurde als veraltet markiert. Die Funktion gibt nun im Fehlerfall statt -1 FALSE zurück. Die Funktion wurde dahingehend gefixt, dass sie für Jahr, Monat und Tag auch den Wert 0 entgegennimmt. |
| 5.1.0 | Wenn ohne Argumente aufgerufen, wirft mktime() eine E_STRICT-Notice. Verwenden Sie stattdessen die Funktion time(). |
| 5.1.0 | Erzeugt nun E_STRICT- und E_NOTICE-Zeitzonenfehler. |
Beispiel #1 Einfaches mktime()-Beispiel
<?php
// Setzt die zu verwendende Standardzeitzone. Verfügbar seit PHP 5.1
date_default_timezone_set('UTC');
// Gibt aus: July 1, 2000 is on a Saturday
echo "July 1, 2000 is on a " . date("l", mktime(0, 0, 0, 7, 1, 2000));
// Gibt etwas aus wie: 2006-04-05T01:02:03+00:00
echo date('c', mktime(1, 2, 3, 4, 5, 2006));
?>
Beispiel #2 mktime()-Beispiel
mktime() ist hilfreich bei Datumsberechnungen und -prüfungen, da automatisch das korrekte Datum für Werte außerhalb der gültigen Bereiche berechnet wird. So wird in den folgenden Beispielen immer die Zeichenkette "Jan-01-1998" ausgegeben.
<?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));
?>
Beispiel #3 Letzter Tag des nächsten Monats
Der letzte Tag eines gegebenen Monats kann als Tag "0" des folgenden Monats ausgedrückt werden, nicht jedoch als Tag "-1". Beide folgenden Beispiele ergeben die Zeichenkette "Letzter Tag im Februar 2000 ist der 29."
<?php
$letzterTag = mktime(0, 0, 0, 3, 0, 2000);
echo strftime("Letzter Tag im Februar 2000 ist der %d.", $letzterTag);
$letzterTag = mktime(0, 0, 0, 4, -31, 2000);
echo strftime("Letzter Tag im Februar 2000 ist der %d.", $letzterTag);
?>
Vor PHP 5.1.0 wurden negative Timestamps von keiner bekannten Windowsversion oder anderen Betriebssystemen unterstützt. Daher war der Bereich gültiger Jahresangaben auf Werte zwischen 1970 und 2038 beschränkt.
Function to generate array of dates between two dates (date range array)
<?php
function dates_range($date1, $date2){
if ($date1<$date2){
$dates_range[]=$date1;
$date1=strtotime($date1);
$date2=strtotime($date2);
while ($date1!=$date2){
$date1=mktime(0, 0, 0, date("m", $date1), date("d", $date1)+1, date("Y", $date1));
$dates_range[]=date('Y-m-d', $date1);
}
}
return $dates_range;
}
echo '<pre>';
print_r(dates_range('2009-12-25', '2010-01-05'));
echo '</pre>';
?>
warning: mktime expects parameter 1 to be long
It could be a string that is given to mktime, so it has to be converted into an int.
mktime((int)$h, (int)$m, (int)$s, (int)$m, (int)$d, (int)$y);
One of the many problems with Daylight Saving Time / Summer Time is the ambiguity when a specified local time value can refer to two different actual times! This happens when the local time value is within the relapse range caused by the clocks being set back to proper time. (eg. if the DST/ST bias is +1 hour, and DST/ST terminates at 02:00 local time, a local time value of 01:30 occurs twice in the same day!)
Because the mktime() function only returns one value, it silently chooses whether to return the time-stamp for the first iteration or the second iteration of a specified local time within this critical range.
To get both possible time-stamps for a local time, compatible with any system locale, time zone, and applicable DST/ST rules, the following function can be used:
<?php /*><!--*/
function LocalToUT($LocalYear, $LocalMonth, $LocalMonthDay, $LocalHour24, $LocalMinute, $LocalSecond) {
/* Converts local date/time to Universal Time values. Returns both
possible UT values when local time value is within relapse range
(due to Daylight Saving Time / Summer Time termination).
Notes:
Conversion based on TZ and DST/ST rules used by mktime() function.
UT time-stamps are number of UT seconds since midnight Jan 1, 1970 UTC.
UT does not have leap seconds; a UT second is "stretched" by 2x duration
to maintain synchronization with UTC when a UTC leap second elapses.
Inputs: All inputs are numeric; $LocalHour24 is in 24-hour format.
Returns: Array:
'initial' = UT time-stamp of first occurrence of specified local date/time
'relapse' = UT time-stamp of second occurrence, when local time relapses upon DST/ST termination
*/
$UTValue = mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay, $LocalYear);
$ReturnData = array('initial' => $UTValue, 'relapse' => $UTValue);
//Test for DST/ST transition since prev day
$Bias = $UTValue - mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay - 1, $LocalYear) - 86400; //(-) = DST/ST commence, (+) = DST/ST terminate
if ($Bias == 0) { //No DST/ST transition detected since prev day
//Test for DST/ST transition up to next day
$Bias = mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay + 1, $LocalYear) - $UTValue - 86400; //(-) = DST/ST commence, (+) = DST/ST terminate
}
if ($Bias > 0) { //DST/ST termination detected
if (date('Z', $UTValue) !== date('Z', $UTValue + $Bias)) { //Local time occurred in relapse range; System assumed 1st iteration
$ReturnData['relapse'] = $UTValue + $Bias;
}
if (date('Z', $UTValue - $Bias) !== date('Z', $UTValue)) { //Local time occurred in relapse range; System assumed 2nd iteration
$ReturnData['initial'] = $UTValue - $Bias;
}
//Else local time is outside of relapse range
} //Else no DST/ST transition, or transition is commencement
return $ReturnData;
}
/*--></?php */?>
Do not be confused by the start and end tags; The interleaved PHP-comment and HTML-comment delimiters prevent PHP code containing ">" from appearing as literal text when viewing or editing an HTML file with embedded PHP code.
I've had this query for an event organizer.
<?php
$query = "SELECT MAX(dt_atfrom) FROM tb_date LIMIT 1";
$raw_data = mysql_query($query);
$maxdate = mysql_result($raw_data,0,0);
?>
It would fetch the 'bigger' date of all of those events.
The problem started when having events in the future.
I'll start to explain.
Imagine you're in '2010' and the biggest event date is '2011-06-05'.
$maxdate will return me the correct data '2011-06-05', yet since I was only needing the year i passed this date through the following function:
<?php
maxyear = date("Y", mktime($maxdate));
?>
mktime was returning me the actual year for every future event instead of the future year.
I ended up doing the following:
<?php
$maxyear = substr($maxdate,0,4);
?>
Probably there's a better solution...
I was using the following to get a list of month names.
for ($i=1; $i<13; $i++) {
echo date('F', mktime(0,0,0,$i) . ",";
}
Normally this outputs -
January,February,March,April,May,June,July,August,
September,October,November,December
However if today's date is the 31st you get instead:
January,March,March,May,May,July,July,August,October,
October,December,December
Why? Because Feb,Apr,June,Sept, and Nov don't have 31 days!
The fix, add the 5th parameter, don't let the day of month default to today's date:
echo date('F', mktime(0,0,0,$i,1) . ",";
Proper way to convert Excel dates into PHP-friendly timestamps using mktime():
<?php
// The date 6/30/2009 is stored as 39994 in Excel
$days = 39994;
// But you must subtract 1 to get the correct timestamp
$ts = mktime(0,0,0,1,$days-1,1900);
// So, this would then match Excel's representation:
echo date("m/d/Y",$ts);
?>
Excel uses "number of days since Jan. 1, 1900" to store its dates. It also treats 1900 as a leap year when it wasn't, thus there is an extra day which must be accounted for in PHP (and the rest of the world). Subtracting 1 from Excel's number will fix this problem.
How many days have passed since the beginning of the year.... regardless of what year it is...
<?php
//Carlos Galindo
//phpmember.com
$days = floor((time()-mktime(null,null,null,1,0,date("Y")))/86400);
echo "$days days have passed";
//Good Luck
?>
I couldn't find any correct date differentiate function anywhere so I wrote this one which works correctly. It's fully resistant to all troubles with different day count of the month or leap year.
Input must be two timestamps and output is associative array with year, month, day, hour, minute, second items.
It can be used for exact age or similar issues.
<?php
function date_diff($d1, $d2){
/* compares two timestamps and returns array with differencies (year, month, day, hour, minute, second)
*/
//check higher timestamp and switch if neccessary
if ($d1 < $d2){
$temp = $d2;
$d2 = $d1;
$d1 = $temp;
}
else {
$temp = $d1; //temp can be used for day count if required
}
$d1 = date_parse(date("Y-m-d H:i:s",$d1));
$d2 = date_parse(date("Y-m-d H:i:s",$d2));
//seconds
if ($d1['second'] >= $d2['second']){
$diff['second'] = $d1['second'] - $d2['second'];
}
else {
$d1['minute']--;
$diff['second'] = 60-$d2['second']+$d1['second'];
}
//minutes
if ($d1['minute'] >= $d2['minute']){
$diff['minute'] = $d1['minute'] - $d2['minute'];
}
else {
$d1['hour']--;
$diff['minute'] = 60-$d2['minute']+$d1['minute'];
}
//hours
if ($d1['hour'] >= $d2['hour']){
$diff['hour'] = $d1['hour'] - $d2['hour'];
}
else {
$d1['day']--;
$diff['hour'] = 24-$d2['hour']+$d1['hour'];
}
//days
if ($d1['day'] >= $d2['day']){
$diff['day'] = $d1['day'] - $d2['day'];
}
else {
$d1['month']--;
$diff['day'] = date("t",$temp)-$d2['day']+$d1['day'];
}
//months
if ($d1['month'] >= $d2['month']){
$diff['month'] = $d1['month'] - $d2['month'];
}
else {
$d1['year']--;
$diff['month'] = 12-$d2['month']+$d1['month'];
}
//years
$diff['year'] = $d1['year'] - $d2['year'];
return $diff;
}
$born_date = mktime(6,30,0,7,24,2008);
$date_diff_array = date_diff($born_date, time());
print_r($date_diff_array);
?>
to ADD or SUBSTRACT times NOTE that if you dont specify the UTC zone your result is the difference +- your server UTC delay.
if you are ina utc/GMT +1
<?php
$hours_diff = strtotime("20:00:00")-strtotime("19:00:00");
echo date('h:i', $hours_diff)." Hours";
?>
it shows: 02:00 Hours
but if you use a default UTC time:
<?php
date_default_timezone_set('UTC');
$hours_diff = strtotime("20:00:00")-strtotime("19:00:00");
echo "<br>". date('h:i', $hours_diff);
?>
it shows: 01:00 Hours.
How to get the first and last dates of the last quarter - useful for things like tax return dates etc. by Justin
<?php
function getLastQuarter() {
// Returns an array with a start and end date for the last quarter from todays date
// eg. If today is 23 Feb 2009, returns $x['start'] = 1 Oct 2008, $x[end] = 31 Dec 2008
$year = date("Y",mktime());
$month = date("m",mktime());
// Formula to get a quarter in the year from a month
$startmth = $month - 3 - (($month-1) % 3 );
// Fix up Jan - Feb to get LAST year's quarter dates (Oct - Dec)
if ($startmth == -2) {
$startmth+=12;
$year-=1;
}
$endmth = $startmth+2;
$last_quarter['start'] = mktime(0,0,0,$startmth,1,$year);
$last_quarter['end'] = mktime(0,0,0,$endmth,date("t",mktime(0,0,0,$endmth,1,$year)),$year);
return $last_quarter;
}
// Example - print first and last dates of last quarter.
echo "First day of last quarter was : " . date("d-M-Y",$lastquarter['start']) . "\n";
echo "Last day of last quarter was : " . date("d-M-Y",$lastquarter['end']) . "\n";
// For 2 August 2009, returns:
// First day of last quarter was : 01-Apr-2009
// Last day of last quarter was : 30-Jun-2009
//
?>
Convert timestamp to time();
<?php
function wp_mktime($_timestamp = ''){
if($_timestamp){
$_split_datehour = explode(' ',$_timestamp);
$_split_data = explode("-", $_split_datehour[0]);
$_split_hour = explode(":", $_split_datehour[1]);
return mktime ($_split_hour[0], $_split_hour[1], $_split_hour[2], $_split_data[1], $_split_data[2], $_split_data[0]);
}
}
?>
[NOTE BY danbrown AT php DOT net: See also (http://php.net/strtotime)]
With combination of mktime and getDate and date() you can add hours / seconds / days / months / years to ANY timestamp. Use strtotime() function to convert any type of dates to timestamp
<?php
public function addMonthToDate($timeStamp, $totalMonths=1){
// You can add as many months as you want. mktime will accumulate to the next year.
$thePHPDate = getdate($timeStamp); // Covert to Array
$thePHPDate['mon'] = $thePHPDate['mon']+$totalMonths; // Add to Month
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']); // Convert back to timestamp
return $timeStamp;
}
public function addDayToDate($timeStamp, $totalDays=1){
// You can add as many days as you want. mktime will accumulate to the next month / year.
$thePHPDate = getdate($timeStamp);
$thePHPDate['mday'] = $thePHPDate['mday']+$totalDays;
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']);
return $timeStamp;
}
public function addYearToDate($timeStamp, $totalYears=1){
$thePHPDate = getdate($timeStamp);
$thePHPDate['year'] = $thePHPDate['year']+$totalYears;
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']);
return $timeStamp;
}
?>
Add (and subtract) unixtime:
<?php
function utime_add($unixtime, $hr=0, $min=0, $sec=0, $mon=0, $day=0, $yr=0) {
$dt = localtime($unixtime, true);
$unixnewtime = mktime(
$dt['tm_hour']+$hr, $dt['tm_min']+$min, $dt['tm_sec']+$sec,
$dt['tm_mon']+1+$mon, $dt['tm_mday']+$day, $dt['tm_year']+1900+$yr);
return $unixnewtime;
}
?>
Days until Christmas:
<?php
$time = mktime(0, 0, 0, 12, 25, 2008, 1) - time();
$days = floor($time/86400);
$hours = floor(($time-($days*86400))/3600);
$mins = floor (($time-($days*86400)-($hours*3600))/60);
$secs = floor ($time-($days*86400)-($hours*3600)-($mins*60));
$tsecs = $time;
$thours = round($time/3600);
if ($tsecs <= 600) {
echo '<html> <head> <title> ' . $tsecs . ' seconds left until 12am Christmas Day </title> <meta http-equiv="refresh" content="1;url=""></head> <body><span
style="font-size:10pt">Christmas day in ' . $days . ' days ' . $hours . ' hours ' . $mins . ' mins ' . $secs . ' seconds!<br><br>(There are ' . $tsecs . ' seconds in
total)</span></body></html>';
} else {
echo '<html> <head> <title> ' . $thours . ' hours left until 12am Christmas Day </title> <meta http-equiv="refresh" content="10;url=""></head> <body><span
style="font-size:10pt">Christmas day in ' . $days . ' days ' . $hours . ' hours ' . $mins . ' mins ' . $secs . ' seconds!<br><br>(There are ' . number_format($thours)
. ' hours in total and ' . number_format($tsecs) . ' seconds in total)</span></body></html>';
}
?>
Do remember that, counter-intuitively enough, the arguments for month and day are inversed (or middle-endian). A common mistake for Europeans seems to be to feed the date arguments in the expected order (big endian or little endian).
It's clear to see where this weird order comes from (even with the date being big endian the order for all arguments would still be mixed - it's obviously based on the American date format with the time "prefixed" to allow an easier shorthand) and why this wasn't changed (passing the values in the wrong order produces a valid, though unexpected, result in most cases), but it continues to be a source of confusion for me whenever I come back to PHP from other languages or libraries.
<?php
//example of functions to know if a date/time value is in summer hour or in winter hour
//====================
function getChgWinDate($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";
}
?>
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....
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;
?>
When calling mktime(), be sure that you use values without leading zeros. The date comes out wrong in the following example:
$endts = mktime(12, 00, 00, 12, 08, 2008, 0);
(note the 08 instead of just 8)
C's scanf() has a format specification where leading 0's can indicate an octal value - perhaps this is related?
zola at zolaweb:
Your expression date('U', strtotime($mydate)) evaluates to strtotime($mydate). Converting to a UNIX timestamp is what strtotime() does.
Here is what I use to calculate age. It took me 30 minutes to write and it's quite accurate. What it has special is that it's calculating the number of days a year has (float number), by testing if a year is a leap one or not. This number is used to compute the age.
<?php
function get_age($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
)
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.
It seems mktime() doesn't return negative timestamps on Linux systems with a version of glibc <= 2.3.3.
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.)
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().
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 , $i , 1 )
?>
Finding out the number of days in a given month and year, accounting for leap years when February has more than 28 days.
<?php
function days_in_month($year, $month) {
return( date( "t", mktime( 0, 0, 0, $month, 1, $year) ) );
}
?>
Hope it helps a soul out there.
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.
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
?>
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.
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
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
?>
Negative timestamps give problem also using linux as guest operating system inside WMvare with Windows host operating system.
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));
?>
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")));
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.
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()
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
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