int mktime ( [int hour [, int minute [, int second [, int month [, int day [, int year [, int is_dst]]]]]]] )
Returns the Unix timestamp corresponding to the arguments
given. This timestamp is a long integer containing the number of
seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time
specified.
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, although this limitation is
overcome as of PHP 5.1.0.
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).
ChangeLog
Version
Description
3.0.10
Added is_dst parameter
5.1.0
The is_dst parameter became deprecated.
Made the function return FALSE on error, instead of
-1.
Fixed the function to accept the year, month and day to be all passed
as zero.
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".
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.
