mktime
(PHP 4, PHP 5) mktime — Get Unix timestamp for a date
Description
int mktime
([ int $hour
[, int $minute
[, int $second
[, int $month
[, int $day
[, int $year
[, int $is_dst
]]]]]]] )
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.
Parameters
-
hour
-
The number of the hour.
-
minute
-
The number of the minute.
-
second
-
The number of seconds past the minute.
-
month
-
The number of the month.
-
day
-
The number of the day.
-
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 message
if using the system settings or the TZ environment
variable. See also date_default_timezone_set()
Examples
Example #1 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 #2 Last day of next 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.
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