socket-create-pair.xml

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<refentry xml:id="function.socket-create-pair" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>socket_create_pair</refname>
  <refpurpose>Creates a pair of indistinguishable sockets and stores them in an array</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>socket_create_pair</methodname>
   <methodparam><type>int</type><parameter>domain</parameter></methodparam>
   <methodparam><type>int</type><parameter>type</parameter></methodparam>
   <methodparam><type>int</type><parameter>protocol</parameter></methodparam>
   <methodparam><type>array</type><parameter role="reference">pair</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>socket_create_pair</function> creates two connected and
   indistinguishable sockets, and stores them in <parameter>pair</parameter>.
   This function is commonly used in IPC (InterProcess Communication).
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>domain</parameter></term>
     <listitem>
      <para>
       The <parameter>domain</parameter> parameter specifies the protocol
       family to be used by the socket. See <function>socket_create</function>
       for the full list.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>type</parameter></term>
     <listitem>
      <para>
       The <parameter>type</parameter> parameter selects the type of communication
       to be used by the socket. See <function>socket_create</function> for the 
       full list.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>protocol</parameter></term>
     <listitem>
      <para>
       The <parameter>protocol</parameter> parameter sets the specific
       protocol within the specified <parameter>domain</parameter> to be used
       when communicating on the returned socket. The proper value can be retrieved by
       name by using <function>getprotobyname</function>. If
       the desired protocol is TCP, or UDP the corresponding constants
       <constant>SOL_TCP</constant>, and <constant>SOL_UDP</constant>
       can also be used.
      </para>
      <para>
       See <function>socket_create</function> for the full list of supported 
       protocols.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>pair</parameter></term>
     <listitem>
      <para>
       Reference to an array in which the two <classname>Socket</classname> instances will be inserted.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.0.0</entry>
      <entry>
       <parameter>pair</parameter> is a reference to an array of <classname>Socket</classname> instances now;
       previously, it was a reference to an array of <type>resource</type>s.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>socket_create_pair</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$sockets = array();

/* On Windows we need to use AF_INET */
$domain = (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN' ? AF_INET : AF_UNIX);

/* Setup socket pair */
if (socket_create_pair($domain, SOCK_STREAM, 0, $sockets) === false) {
    echo "socket_create_pair failed. Reason: ".socket_strerror(socket_last_error());
}
/* Send and Receive Data */
if (socket_write($sockets[0], "ABCdef123\n", strlen("ABCdef123\n")) === false) {
    echo "socket_write() failed. Reason: ".socket_strerror(socket_last_error($sockets[0]));
}
if (($data = socket_read($sockets[1], strlen("ABCdef123\n"), PHP_BINARY_READ)) === false) {
    echo "socket_read() failed. Reason: ".socket_strerror(socket_last_error($sockets[1]));
}
var_dump($data);

/* Close sockets */
socket_close($sockets[0]);
socket_close($sockets[1]);
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title><function>socket_create_pair</function> IPC example</title>
    <programlisting role="php">
<![CDATA[
<?php
$ary = array();
$strone = 'Message From Parent.';
$strtwo = 'Message From Child.';

if (socket_create_pair(AF_UNIX, SOCK_STREAM, 0, $ary) === false) {
    echo "socket_create_pair() failed. Reason: ".socket_strerror(socket_last_error());
}
$pid = pcntl_fork();
if ($pid == -1) {
    echo 'Could not fork Process.';
} elseif ($pid) {
    /*parent*/
    socket_close($ary[0]);
    if (socket_write($ary[1], $strone, strlen($strone)) === false) {
        echo "socket_write() failed. Reason: ".socket_strerror(socket_last_error($ary[1]));
    }
    if (socket_read($ary[1], strlen($strtwo), PHP_BINARY_READ) == $strtwo) {
        echo "Received $strtwo\n";
    }
    socket_close($ary[1]);
} else {
    /*child*/
    socket_close($ary[1]);
    if (socket_write($ary[0], $strtwo, strlen($strtwo)) === false) {
        echo "socket_write() failed. Reason: ".socket_strerror(socket_last_error($ary[0]));
    }
    if (socket_read($ary[0], strlen($strone), PHP_BINARY_READ) == $strone) {
        echo "Received $strone\n";
    }
    socket_close($ary[0]);
}
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>socket_create</function></member>
    <member><function>socket_create_listen</function></member>
    <member><function>socket_bind</function></member>
    <member><function>socket_listen</function></member>
    <member><function>socket_last_error</function></member>
    <member><function>socket_strerror</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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