php-doc-en/reference/datetime/functions/mktime.xml
Adam Harvey 18731686ea Fix doc bug (All date acceptance functions should cross-reference
checkdate()) by cross referencing checkdate().


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@309064 c90b9560-bf6c-de11-be94-00142212c4b1
2011-03-10 07:13:07 +00:00

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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- splitted from ./en/functions/datetime.xml, last change in rev 1.2 -->
<refentry xml:id="function.mktime" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>mktime</refname>
<refpurpose>Get Unix timestamp for a date</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>int</type><methodname>mktime</methodname>
<methodparam choice="opt"><type>int</type><parameter>hour</parameter><initializer>date("H")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>minute</parameter><initializer>date("i")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>second</parameter><initializer>date("s")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>month</parameter><initializer>date("n")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>day</parameter><initializer>date("j")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>year</parameter><initializer>date("Y")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>is_dst</parameter><initializer>-1</initializer></methodparam>
</methodsynopsis>
<para>
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.
</para>
<para>
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.
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<note>
<para>
As of PHP 5.1, when called with no arguments, <function>mktime</function>
throws an <constant>E_STRICT</constant> notice: use the
<function>time</function> function instead.
</para>
</note>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>hour</parameter></term>
<listitem>
<para>
The number of the hour relevant to the start of the day determined by
<parameter>month</parameter>, <parameter>day</parameter> and <parameter>year</parameter>.
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).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>minute</parameter></term>
<listitem>
<para>
The number of the minute relevant to the start of the <parameter>hour</parameter>.
Negative values reference the minute in the previous hour.
Values greater than 59 reference the appropriate minute in the following hour(s).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>second</parameter></term>
<listitem>
<para>
The number of seconds relevant to the start of the <parameter>minute</parameter>.
Negative values reference the second in the previous minute.
Values greater than 59 reference the appropriate second in the following minute(s).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>month</parameter></term>
<listitem>
<para>
The number of the month relevant 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).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>day</parameter></term>
<listitem>
<para>
The number of the day relevant 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).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>year</parameter></term>
<listitem>
<para>
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 <parameter>year</parameter>
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).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>is_dst</parameter></term>
<listitem>
<para>
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
<parameter>is_dst</parameter> is set to 1. If DST is enabled in e.g. 2:00, all times
between 2:00 and 3:00 are invalid and <function>mktime</function> 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.
</para>
<note>
<para>
As of PHP 5.1.0, this parameter became deprecated. As a result, the
new timezone handling features should be used instead.
</para>
</note>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
<function>mktime</function> returns the Unix timestamp of the arguments
given.
If the arguments are invalid, the function returns &false; (before PHP 5.1
it returned <literal>-1</literal>).
</para>
</refsect1>
<refsect1 role="errors">
&reftitle.errors;
&date.timezone.errors.description;
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<para>
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>5.3.0</entry>
<entry>
<function>mktime</function> now throws <constant>E_DEPRECATED</constant> notice
if the <parameter>is_dst</parameter> parameter is used.
</entry>
</row>
<row>
<entry>5.1.0</entry>
<entry>
The <parameter>is_dst</parameter> parameter became deprecated.
Made the function return &false; on error, instead of
<literal>-1</literal>.
Fixed the function to accept the year, month and day to be all passed
as zero.
</entry>
</row>
<row>
<entry>5.1.0</entry>
<entry>
When called with no arguments, <function>mktime</function> throws
<constant>E_STRICT</constant> notice. Use the
<function>time</function> function instead.
</entry>
</row>
&date.timezone.errors.changelog;
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>mktime</function> basic example</title>
<programlisting role="php">
<![CDATA[
<?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));
?>
]]>
</programlisting>
</example>
</para>
<para>
<example>
<title><function>mktime</function> example</title>
<para>
<function>mktime</function> 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".
</para>
<programlisting role="php">
<![CDATA[
<?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));
?>
]]>
</programlisting>
</example>
</para>
<para>
<example>
<title>Last day of next month</title>
<para>
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".
</para>
<programlisting role="php">
<![CDATA[
<?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);
?>
]]>
</programlisting>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<caution>
<para>
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.
</para>
</caution>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>checkdate</function></member>
<member><function>gmmktime</function></member>
<member><function>date</function></member>
<member><function>time</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
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