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<!-- $Revision$ -->
<refentry xml:id="function.preg-match-all" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>preg_match_all</refname>
  <refpurpose>Perform a global regular expression match</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>int</type><type>false</type></type><methodname>preg_match_all</methodname>
   <methodparam><type>string</type><parameter>pattern</parameter></methodparam>
   <methodparam><type>string</type><parameter>subject</parameter></methodparam>
   <methodparam choice="opt"><type>array</type><parameter role="reference">matches</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>0</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>offset</parameter><initializer>0</initializer></methodparam>
  </methodsynopsis>
  <para>
   Searches <parameter>subject</parameter> for all matches to the regular
   expression given in <parameter>pattern</parameter> and puts them in
   <parameter>matches</parameter> in the order specified by
   <parameter>flags</parameter>.
  </para>
  <para>
   After the first match is found, the subsequent searches  are continued
   on from end of the last match.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>pattern</parameter></term>
     <listitem>
      <para>
       The pattern to search for, as a string.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>subject</parameter></term>
     <listitem>
      <para>
       The input string.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>matches</parameter></term>
     <listitem>
      <para>
       Array of all matches in multi-dimensional array ordered according to
       <parameter>flags</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>flags</parameter></term>
     <listitem>
      <para>
       Can be a combination of the following flags (note that it doesn't make
       sense to use <constant>PREG_PATTERN_ORDER</constant> together with
       <constant>PREG_SET_ORDER</constant>):
       <variablelist>
        <varlistentry>
         <term><constant>PREG_PATTERN_ORDER</constant></term>
         <listitem>
          <para>
           Orders results so that <varname>$matches[0]</varname> is an array of full
           pattern matches, <varname>$matches[1]</varname> is an array of strings matched by
           the first parenthesized subpattern, and so on.
          </para>
          <para>
           <informalexample>
            <programlisting role="php">
<![CDATA[
<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
    "<b>example: </b><div align=left>this is a test</div>",
    $out, PREG_PATTERN_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>
]]>
            </programlisting>
            &example.outputs;
            <screen role="html">
<![CDATA[
<b>example: </b>, <div align=left>this is a test</div>
example: , this is a test
]]>
            </screen>
            <para>
             So, <varname>$out[0]</varname> contains an array of strings that matched the full pattern,
             and <varname>$out[1]</varname> contains an array of strings enclosed by tags.
            </para>
           </informalexample>
          </para>
          <para>
           If the pattern contains named subpatterns, <varname>$matches</varname>
           additionally contains entries for keys with the subpattern name.
          </para>
          <para>
           If the pattern contains duplicate named subpatterns, only the rightmost
           subpattern is stored in <varname>$matches[NAME]</varname>.
           <informalexample>
            <programlisting role="php">
<![CDATA[
<?php
preg_match_all(
    '/(?J)(?<match>foo)|(?<match>bar)/',
    'foo bar',
    $matches,
    PREG_PATTERN_ORDER
);
print_r($matches['match']);
?>
]]>
            </programlisting>
            &example.outputs;
            <screen>
<![CDATA[
Array
(
    [0] => 
    [1] => bar
)
]]>
            </screen>
           </informalexample>
          </para>
         </listitem>
        </varlistentry>
        <varlistentry>
         <term><constant>PREG_SET_ORDER</constant></term>
         <listitem>
          <para>
           Orders results so that <varname>$matches[0]</varname> is an array of first set
           of matches, <varname>$matches[1]</varname> is an array of second set of matches,
           and so on.
           <informalexample>
            <programlisting role="php">
<![CDATA[
<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
    "<b>example: </b><div align=\"left\">this is a test</div>",
    $out, PREG_SET_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>
]]>
            </programlisting>
            &example.outputs;
            <screen role="html">
<![CDATA[
<b>example: </b>, example:
<div align="left">this is a test</div>, this is a test
]]>
            </screen>
           </informalexample>
          </para>
         </listitem>
        </varlistentry>
        <varlistentry>
         <term><constant>PREG_OFFSET_CAPTURE</constant></term>
         <listitem>
          <para>
           If this flag is passed, for every occurring match the appendant string
           offset (in bytes) will also be returned. Note that this changes the value of
           <parameter>matches</parameter> into an array of arrays where every element is an
           array consisting of the matched string at offset <literal>0</literal>
           and its string offset into <parameter>subject</parameter> at offset
           <literal>1</literal>.
           <informalexample>
            <programlisting role="php">
<![CDATA[
<?php
preg_match_all('/(foo)(bar)(baz)/', 'foobarbaz', $matches, PREG_OFFSET_CAPTURE);
print_r($matches);
?>
]]>
            </programlisting>
            &example.outputs;
            <screen>
<![CDATA[
Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [0] => foobarbaz
                    [1] => 0
                )

        )

    [1] => Array
        (
            [0] => Array
                (
                    [0] => foo
                    [1] => 0
                )

        )

    [2] => Array
        (
            [0] => Array
                (
                    [0] => bar
                    [1] => 3
                )

        )

    [3] => Array
        (
            [0] => Array
                (
                    [0] => baz
                    [1] => 6
                )

        )

)
]]>
            </screen>
           </informalexample>
          </para>
         </listitem>
        </varlistentry>
        <varlistentry>
         <term><constant>PREG_UNMATCHED_AS_NULL</constant></term>
         <listitem>
          <para>
           If this flag is passed, unmatched subpatterns are reported as &null;;
           otherwise they are reported as an empty <type>string</type>.
          </para>
         </listitem>
        </varlistentry>  
       </variablelist>
      </para>
      <para>
       If no order flag is given, <constant>PREG_PATTERN_ORDER</constant> is
       assumed.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>offset</parameter></term>
     <listitem>
      <para>
       Normally, the search starts from the beginning of the subject string.
       The optional parameter <parameter>offset</parameter> can be used to
       specify the alternate place from which to start the search (in bytes).
      </para>
      <note>
       <para>
        Using <parameter>offset</parameter> is not equivalent to passing
        <code>substr($subject, $offset)</code> to
        <function>preg_match_all</function> in place of the subject string,
        because <parameter>pattern</parameter> can contain assertions such as
        <emphasis>^</emphasis>, <emphasis>$</emphasis> or
        <emphasis>(?&lt;=x)</emphasis>. See <function>preg_match</function>
        for examples.
       </para>
      </note>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the number of full pattern matches (which might be zero),&return.falseforfailure;.
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  &pcre.pattern.warning;
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>7.2.0</entry>
       <entry>
        The <constant>PREG_UNMATCHED_AS_NULL</constant> is now supported for the
        <parameter>$flags</parameter> parameter.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Getting all phone numbers out of some text.</title>
    <programlisting role="php">
<![CDATA[
<?php
preg_match_all("/\(?  (\d{3})?  \)?  (?(1)  [\-\s] ) \d{3}-\d{4}/x",
                "Call 555-1212 or 1-800-555-1212", $phones);
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title>Find matching HTML tags (greedy)</title>
    <programlisting role="php">
<![CDATA[
<?php
// The \\2 is an example of backreferencing. This tells pcre that
// it must match the second set of parentheses in the regular expression
// itself, which would be the ([\w]+) in this case. The extra backslash is
// required because the string is in double quotes.
$html = "<b>bold text</b><a href=howdy.html>click me</a>";

preg_match_all("/(<([\w]+)[^>]*>)(.*?)(<\/\\2>)/", $html, $matches, PREG_SET_ORDER);

foreach ($matches as $val) {
    echo "matched: " . $val[0] . "\n";
    echo "part 1: " . $val[1] . "\n";
    echo "part 2: " . $val[2] . "\n";
    echo "part 3: " . $val[3] . "\n";
    echo "part 4: " . $val[4] . "\n\n";
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen role="html">
<![CDATA[
matched: <b>bold text</b>
part 1: <b>
part 2: b
part 3: bold text
part 4: </b>

matched: <a href=howdy.html>click me</a>
part 1: <a href=howdy.html>
part 2: a
part 3: click me
part 4: </a>
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>Using named subpattern</title>
    <programlisting role="php">
<![CDATA[
<?php

$str = <<<FOO
a: 1
b: 2
c: 3
FOO;

preg_match_all('/(?P<name>\w+): (?P<digit>\d+)/', $str, $matches);

/* Alternative */
// preg_match_all('/(?<name>\w+): (?<digit>\d+)/', $str, $matches);

print_r($matches);

?>
]]>
    </programlisting>
    &example.outputs;
    <screen role="html">
<![CDATA[
Array
(
    [0] => Array
        (
            [0] => a: 1
            [1] => b: 2
            [2] => c: 3
        )

    [name] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )

    [1] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )

    [digit] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [2] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

)
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><link linkend="pcre.pattern">PCRE Patterns</link></member>
    <member><function>preg_quote</function></member>
    <member><function>preg_match</function></member>
    <member><function>preg_replace</function></member>
    <member><function>preg_split</function></member>
    <member><function>preg_last_error</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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