date.xml

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<!-- $Revision$ -->
<refentry xml:id="function.date" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>date</refname>
  <refpurpose>Format a local time/date</refpurpose>
 </refnamediv>
  
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>string</type><methodname>date</methodname>
   <methodparam><type>string</type><parameter>format</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>timestamp</parameter><initializer>time()</initializer></methodparam>
  </methodsynopsis>
  <para>
   Returns a string formatted according to the given format string using the
   given integer <parameter>timestamp</parameter> or the current time
   if no timestamp is given.  In other words, <parameter>timestamp</parameter>
   is optional and defaults to the value of <function>time</function>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>format</parameter></term>
     <listitem>
      <para>
       The format of the outputted date <type>string</type>. See the formatting
       options below. There are also several
       <link linkend="datetime.constants.types">predefined date constants</link>
       that may be used instead, so for example <constant>DATE_RSS</constant>
       contains the format string <literal>'D, d M Y H:i:s'</literal>.
      </para>
      <para>
       <table>
        <title>The following characters are recognized in the
        <parameter>format</parameter> parameter string</title>
        <tgroup cols="3">
         <thead>
          <row>
           <entry><parameter>format</parameter> character</entry>
           <entry>Description</entry>
           <entry>Example returned values</entry>
          </row>
         </thead>
         <tbody>
          <row>
           <entry align="center"><emphasis>Day</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>d</literal></entry>
           <entry>Day of the month, 2 digits with leading zeros</entry>
           <entry><literal>01</literal> to <literal>31</literal></entry>
          </row>
          <row>
           <entry><literal>D</literal></entry>
           <entry>A textual representation of a day, three letters</entry>
           <entry><literal>Mon</literal> through <literal>Sun</literal></entry>
          </row>
          <row>
           <entry><literal>j</literal></entry>
           <entry>Day of the month without leading zeros</entry>
           <entry><literal>1</literal> to <literal>31</literal></entry>
          </row>
          <row>
           <entry><literal>l</literal> (lowercase 'L')</entry>
           <entry>A full textual representation of the day of the week</entry>
           <entry><literal>Sunday</literal> through <literal>Saturday</literal></entry>
          </row>
          <row>
           <entry><literal>N</literal></entry>
           <entry>ISO-8601 numeric representation of the day of the week (added in
           PHP 5.1.0)</entry>
           <entry><literal>1</literal> (for Monday) through <literal>7</literal> (for Sunday)</entry>
          </row>
          <row>
           <entry><literal>S</literal></entry>
           <entry>English ordinal suffix for the day of the month, 2 characters</entry>
           <entry>
            <literal>st</literal>, <literal>nd</literal>, <literal>rd</literal> or
            <literal>th</literal>.  Works well with <literal>j</literal>
           </entry>
          </row>
          <row>
           <entry><literal>w</literal></entry>
           <entry>Numeric representation of the day of the week</entry>
           <entry><literal>0</literal> (for Sunday) through <literal>6</literal> (for Saturday)</entry>
          </row>
          <row>
           <entry><literal>z</literal></entry>
           <entry>The day of the year (starting from 0)</entry>
           <entry><literal>0</literal> through <literal>365</literal></entry>
          </row>
          <row>
           <entry align="center"><emphasis>Week</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>W</literal></entry>
           <entry>ISO-8601 week number of year, weeks starting on Monday (added in PHP 4.1.0)</entry>
           <entry>Example: <literal>42</literal> (the 42nd week in the year)</entry>
          </row>
          <row>
           <entry align="center"><emphasis>Month</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>F</literal></entry>
           <entry>A full textual representation of a month, such as January or March</entry>
           <entry><literal>January</literal> through <literal>December</literal></entry>
          </row>
          <row>
           <entry><literal>m</literal></entry>
           <entry>Numeric representation of a month, with leading zeros</entry>
           <entry><literal>01</literal> through <literal>12</literal></entry>
          </row>
          <row>
           <entry><literal>M</literal></entry>
           <entry>A short textual representation of a month, three letters</entry>
           <entry><literal>Jan</literal> through <literal>Dec</literal></entry>
          </row>
          <row>
           <entry><literal>n</literal></entry>
           <entry>Numeric representation of a month, without leading zeros</entry>
           <entry><literal>1</literal> through <literal>12</literal></entry>
          </row>
          <row>
           <entry><literal>t</literal></entry>
           <entry>Number of days in the given month</entry>
           <entry><literal>28</literal> through <literal>31</literal></entry>
          </row>
          <row>
           <entry align="center"><emphasis>Year</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>L</literal></entry>
           <entry>Whether it's a leap year</entry>
           <entry><literal>1</literal> if it is a leap year, <literal>0</literal> otherwise.</entry>
          </row>
          <row>
           <entry><literal>o</literal></entry>
           <entry>ISO-8601 year number. This has the same value as
            <literal>Y</literal>, except that if the ISO week number
            (<literal>W</literal>) belongs to the previous or next year, that year
            is used instead. (added in PHP 5.1.0)</entry>
           <entry>Examples: <literal>1999</literal> or <literal>2003</literal></entry>
          </row>
          <row>
           <entry><literal>Y</literal></entry>
           <entry>A full numeric representation of a year, 4 digits</entry>
           <entry>Examples: <literal>1999</literal> or <literal>2003</literal></entry>
          </row>
          <row>
           <entry><literal>y</literal></entry>
           <entry>A two digit representation of a year</entry>
           <entry>Examples: <literal>99</literal> or <literal>03</literal></entry>
          </row>
          <row>
           <entry align="center"><emphasis>Time</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>a</literal></entry>
           <entry>Lowercase Ante meridiem and Post meridiem</entry>
           <entry><literal>am</literal> or <literal>pm</literal></entry>
          </row>
          <row>
           <entry><literal>A</literal></entry>
           <entry>Uppercase Ante meridiem and Post meridiem</entry>
           <entry><literal>AM</literal> or <literal>PM</literal></entry>
          </row>
          <row>
           <entry><literal>B</literal></entry>
           <entry>Swatch Internet time</entry>
           <entry><literal>000</literal> through <literal>999</literal></entry>
          </row>
          <row>
           <entry><literal>g</literal></entry>
           <entry>12-hour format of an hour without leading zeros</entry>
           <entry><literal>1</literal> through <literal>12</literal></entry>
          </row>
          <row>
           <entry><literal>G</literal></entry>
           <entry>24-hour format of an hour without leading zeros</entry>
           <entry><literal>0</literal> through <literal>23</literal></entry>
          </row>
          <row>
           <entry><literal>h</literal></entry>
           <entry>12-hour format of an hour with leading zeros</entry>
           <entry><literal>01</literal> through <literal>12</literal></entry>
          </row>
          <row>
           <entry><literal>H</literal></entry>
           <entry>24-hour format of an hour with leading zeros</entry>
           <entry><literal>00</literal> through <literal>23</literal></entry>
          </row>
          <row>
           <entry><literal>i</literal></entry>
           <entry>Minutes with leading zeros</entry>
           <entry><literal>00</literal> to <literal>59</literal></entry>
          </row>
          <row>
           <entry><literal>s</literal></entry>
           <entry>Seconds, with leading zeros</entry>
           <entry><literal>00</literal> through <literal>59</literal></entry>
          </row>
          <row>
           <entry><literal>u</literal></entry>
           <entry>Microseconds (added in PHP 5.2.2)</entry>
           <entry>Example: <literal>654321</literal></entry>
          </row>
          <row>
           <entry align="center"><emphasis>Timezone</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>e</literal></entry>
           <entry>Timezone identifier (added in PHP 5.1.0)</entry>
           <entry>Examples: <literal>UTC</literal>, <literal>GMT</literal>, <literal>Atlantic/Azores</literal></entry>
          </row>
          <row>
           <entry><literal>I</literal> (capital i)</entry>
           <entry>Whether or not the date is in daylight saving time</entry>
           <entry><literal>1</literal> if Daylight Saving Time, <literal>0</literal> otherwise.</entry>
          </row>
          <row>
           <entry><literal>O</literal></entry>
           <entry>Difference to Greenwich time (GMT) in hours</entry>
           <entry>Example: <literal>+0200</literal></entry>
          </row>
          <row>
           <entry><literal>P</literal></entry>
           <entry>Difference to Greenwich time (GMT) with colon between hours and minutes (added in PHP 5.1.3)</entry>
           <entry>Example: <literal>+02:00</literal></entry>
          </row>
          <row>
           <entry><literal>T</literal></entry>
           <entry>Timezone abbreviation</entry>
           <entry>Examples: <literal>EST</literal>, <literal>MDT</literal> ...</entry>
          </row>
          <row>
           <entry><literal>Z</literal></entry>
           <entry>Timezone offset in seconds. The offset for timezones west of UTC is always
           negative, and for those east of UTC is always positive.</entry>
           <entry><literal>-43200</literal> through <literal>50400</literal></entry>
          </row>
          <row>
           <entry align="center"><emphasis>Full Date/Time</emphasis></entry>
           <entry>---</entry>
           <entry>---</entry>
          </row>
          <row>
           <entry><literal>c</literal></entry>
           <entry>ISO 8601 date (added in PHP 5)</entry>
           <entry>2004-02-12T15:19:21+00:00</entry>
          </row>
          <row>
           <entry><literal>r</literal></entry>
           <entry><link xlink:href="&url.rfc;2822">RFC 2822</link> formatted date</entry>
           <entry>Example: <literal>Thu, 21 Dec 2000 16:01:07 +0200</literal></entry>
          </row>
          <row>
           <entry><literal>U</literal></entry>
           <entry>Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)</entry>
           <entry>See also <function>time</function></entry>
          </row>
         </tbody>
        </tgroup>
       </table>
      </para>
      <para>
       Unrecognized characters in the format string will be printed
       as-is.  The <literal>Z</literal> format will always return
       <literal>0</literal> when using <function>gmdate</function>.
      </para>       
      <note>
       <para>
        Since this function only accepts <type>integer</type> timestamps the
        <literal>u</literal> format character is only useful when using the
        <function>date_format</function> function with user based timestamps
        created with <function>date_create</function>.
       </para>
      </note>
     </listitem>
    </varlistentry>
    
    &date.timestamp.description;
   
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns a formatted date string. If a non-numeric value is used for 
   <parameter>timestamp</parameter>, &false; is returned and an 
   <constant>E_WARNING</constant> level error is emitted.
  </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>5.1.0</entry>
       <entry>
        The valid range of a timestamp is typically from Fri, 13 Dec
        1901 20:45:54 GMT to Tue, 19 Jan 2038 03:14:07 GMT. (These are
        the dates that correspond to the minimum and maximum values for
        a 32-bit signed integer). However, before PHP 5.1.0 this range was limited
        from 01-01-1970 to 19-01-2038 on some systems (e.g. Windows).
       </entry>
      </row>
      
      &date.timezone.errors.changelog;

      <row>
       <entry>5.1.1</entry>
       <entry>
        There are useful <link linkend="datetime.constants">constants</link> 
        of standard date/time formats that can be used to specify the 
        <parameter>format</parameter> parameter.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>date</function> examples</title>
    <programlisting role="php">
<![CDATA[
<?php
// set the default timezone to use. Available since PHP 5.1
date_default_timezone_set('UTC');


// Prints something like: Monday
echo date("l");

// Prints something like: Monday 8th of August 2005 03:12:46 PM
echo date('l jS \of F Y h:i:s A');

// Prints: July 1, 2000 is on a Saturday
echo "July 1, 2000 is on a " . date("l", mktime(0, 0, 0, 7, 1, 2000));

/* use the constants in the format parameter */
// prints something like: Mon, 15 Aug 2005 15:12:46 UTC
echo date(DATE_RFC822);

// prints something like: 2000-07-01T00:00:00+00:00
echo date(DATE_ATOM, mktime(0, 0, 0, 7, 1, 2000));
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   You can prevent a recognized character in the format string from being
   expanded by escaping it with a preceding backslash. If the character with
   a backslash is already a special sequence, you may need to also escape
   the backslash.
   <example>
    <title>Escaping characters in <function>date</function></title>
    <programlisting role="php">
<![CDATA[
<?php
// prints something like: Wednesday the 15th
echo date('l \t\h\e jS');
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   It is possible to use <function>date</function> and
   <function>mktime</function> together to find dates in the future
   or the past.
   <example>
    <title><function>date</function> and <function>mktime</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$tomorrow  = mktime(0, 0, 0, date("m")  , date("d")+1, date("Y"));
$lastmonth = mktime(0, 0, 0, date("m")-1, date("d"),   date("Y"));
$nextyear  = mktime(0, 0, 0, date("m"),   date("d"),   date("Y")+1);
?>
]]>
    </programlisting>
   </example>
   <note>
    <para>
     This can be more reliable than simply adding or subtracting the number
     of seconds in a day or month to a timestamp because of daylight saving
     time.
    </para>
   </note>
  </para>
  <para>
   Some examples of <function>date</function> formatting. Note that
   you should escape any other characters, as any which currently
   have a special meaning will produce undesirable results, and
   other characters may be assigned meaning in future PHP versions.
   When escaping, be sure to use single quotes to prevent characters
   like \n from becoming newlines.
   <example>
    <title><function>date</function> Formatting</title>
    <programlisting role="php">
<![CDATA[
<?php
// Assuming today is March 10th, 2001, 5:16:18 pm, and that we are in the
// Mountain Standard Time (MST) Time Zone

$today = date("F j, Y, g:i a");                 // March 10, 2001, 5:16 pm
$today = date("m.d.y");                         // 03.10.01
$today = date("j, n, Y");                       // 10, 3, 2001
$today = date("Ymd");                           // 20010310
$today = date('h-i-s, j-m-y, it is w Day');     // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.');   // it is the 10th day.
$today = date("D M j G:i:s T Y");               // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h');     // 17:03:18 m is month
$today = date("H:i:s");                         // 17:16:18
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   To format dates in other languages, you should use the
   <function>setlocale</function> and <function>strftime</function>
   functions instead of <function>date</function>.
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    To generate a timestamp from a string representation of the date, you
    may be able to use <function>strtotime</function>. Additionally, some
    databases have functions to convert their date formats into timestamps
    (such as MySQL's <link xlink:href="&url.mysql.docs.date;">UNIX_TIMESTAMP</link>
    function).
   </para>
  </note>
  <tip>
   <para>
    Timestamp of the start of the request is available in
    <varname>$_SERVER['REQUEST_TIME']</varname> since PHP 5.1.
   </para>
  </tip>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>gmdate</function></member>
    <member><function>idate</function></member>
    <member><function>getdate</function></member>
    <member><function>getlastmod</function></member>
    <member><function>mktime</function></member>
    <member><function>strftime</function></member>
    <member><function>time</function></member>
    <member><function>strtotime</function></member>
    <member><link linkend="datetime.constants.types">Predefined DateTime Constants</link></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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