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mktime
Get Unix timestamp for a date
Description
int mktime
([ int $hour = date("H")
[, int $minute = date("i")
[, int $second = date("s")
[, int $month = date("n")
[, int $day = date("j")
[, int $year = date("Y")
[, int $is_dst = -1
]]]]]]] )
Arguments may be left out in order from right to left; any
arguments thus omitted will be set to the current value according
to the local date and time.
Notes
Note:
As of PHP 5.1, when called with no arguments, mktime
throws an E_STRICT notice: use the
time function instead.
Parameters
-
hour
-
The number of the hour relative to the start of the day determined by
month, day and year.
Negative values reference the hour before midnight of the day in question.
Values greater than 23 reference the appropriate hour in the following day(s).
-
minute
-
The number of the minute relative to the start of the hour.
Negative values reference the minute in the previous hour.
Values greater than 59 reference the appropriate minute in the following hour(s).
-
second
-
The number of seconds relative to the start of the minute.
Negative values reference the second in the previous minute.
Values greater than 59 reference the appropriate second in the following minute(s).
-
month
-
The number of the month relative to the end of the previous year.
Values 1 to 12 reference the normal calendar months of the year in question.
Values less than 1 (including negative values) reference the months in the previous year in reverse order, so 0 is December, -1 is November, etc.
Values greater than 12 reference the appropriate month in the following year(s).
-
day
-
The number of the day relative to the end of the previous month.
Values 1 to 28, 29, 30 or 31 (depending upon the month) reference the normal days in the relevant month.
Values less than 1 (including negative values) reference the days in the previous month, so 0 is the last day of the previous month, -1 is the day before that, etc.
Values greater than the number of days in the relevant month reference the appropriate day in the following month(s).
-
year
-
The number of the year, may be a two or four digit value,
with values between 0-69 mapping to 2000-2069 and 70-100 to
1970-2000. On systems where time_t is a 32bit signed integer, as
most common today, the valid range for year
is somewhere between 1901 and 2038. However, before PHP 5.1.0 this
range was limited from 1970 to 2038 on some systems (e.g. Windows).
-
is_dst
-
This parameter can be set to 1 if the time is during daylight savings time (DST),
0 if it is not, or -1 (the default) if it is unknown whether the time is within
daylight savings time or not. If it's unknown, PHP tries to figure it out itself.
This can cause unexpected (but not incorrect) results.
Some times are invalid if DST is enabled on the system PHP is running on or
is_dst is set to 1. If DST is enabled in e.g. 2:00, all times
between 2:00 and 3:00 are invalid and mktime returns an undefined
(usually negative) value.
Some systems (e.g. Solaris 8) enable DST at midnight so time 0:30 of the day when DST
is enabled is evaluated as 23:30 of the previous day.
Note:
As of PHP 5.1.0, this parameter became deprecated. As a result, the
new timezone handling features should be used instead.
Return Values
mktime returns the Unix timestamp of the arguments
given.
If the arguments are invalid, the function returns FALSE (before PHP 5.1
it returned -1).
Errors/Exceptions
Every call to a date/time function will generate a E_NOTICE
if the time zone is not valid, and/or a E_STRICT
or E_WARNING message
if using the system settings or the TZ environment
variable. See also date_default_timezone_set
Examples
Example #1 mktime basic example
<?php
// Set the default timezone to use. Available as of PHP 5.1
date_default_timezone_set('UTC');
// Prints: July 1, 2000 is on a Saturday
echo "July 1, 2000 is on a " . date("l", mktime(0, 0, 0, 7, 1, 2000));
// Prints something like: 2006-04-05T01:02:03+00:00
echo date('c', mktime(1, 2, 3, 4, 5, 2006));
?>
Example #2 mktime example
mktime is useful for doing date arithmetic
and validation, as it will automatically calculate the correct
value for out-of-range input. For example, each of the following
lines produces the 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));
?>
Example #3 Last day of a month
The last day of any given month can be expressed as the "0" day
of the next month, not the -1 day. Both of the following examples
will produce the 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);
?>
Notes
Caution
Before PHP 5.1.0, negative timestamps were not supported under any known
version of Windows and some other systems as well. Therefore the range of
valid years was limited to 1970 through 2038.
See Also
- checkdate
- gmmktime
- date
- time
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