stream-socket-recvfrom.xml

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<refentry xml:id="function.stream-socket-recvfrom" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>stream_socket_recvfrom</refname>
  <refpurpose>Receives data from a socket, connected or not</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>string</type><type>false</type></type><methodname>stream_socket_recvfrom</methodname>
   <methodparam><type>resource</type><parameter>socket</parameter></methodparam>
   <methodparam><type>int</type><parameter>length</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>0</initializer></methodparam>
   <methodparam choice="opt"><type class="union"><type>string</type><type>null</type></type><parameter role="reference">address</parameter><initializer>&null;</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>stream_socket_recvfrom</function> accepts
   data from a remote socket up to <parameter>length</parameter> bytes.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>socket</parameter></term>
     <listitem>
      <para>
       The remote socket.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>length</parameter></term>
     <listitem>
      <para>
       The number of bytes to receive from the <parameter>socket</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>flags</parameter></term>
     <listitem>
      <para>
       The value of <parameter>flags</parameter> can be any combination
       of the following:
       <table>
        <title>Possible values for <parameter>flags</parameter></title>
        <tgroup cols="2">
         <tbody>
          <row>
           <entry><constant>STREAM_OOB</constant></entry>
           <entry>
            Process OOB (<literal>out-of-band</literal>) data.
           </entry>
          </row>
          <row>
           <entry><constant>STREAM_PEEK</constant></entry>
           <entry>
            Retrieve data from the socket, but do not consume the buffer.
            Subsequent calls to <function>fread</function> or
            <function>stream_socket_recvfrom</function> will see
            the same data.
           </entry>
          </row>
         </tbody>
        </tgroup>
       </table>
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>address</parameter></term>
     <listitem>
      <para>
       If <parameter>address</parameter> is provided it will be populated with
       the address of the remote socket.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the read data, as a string,&return.falseforfailure;.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>stream_socket_recvfrom</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
/* Open a server socket to port 1234 on localhost */
$server = stream_socket_server('tcp://127.0.0.1:1234');

/* Accept a connection */
$socket = stream_socket_accept($server);

/* Grab a packet (1500 is a typical MTU size) of OOB data */
echo "Received Out-Of-Band: '" . stream_socket_recvfrom($socket, 1500, STREAM_OOB) . "'\n";

/* Take a peek at the normal in-band data, but don't consume it. */
echo "Data: '" . stream_socket_recvfrom($socket, 1500, STREAM_PEEK) . "'\n";

/* Get the exact same packet again, but remove it from the buffer this time. */
echo "Data: '" . stream_socket_recvfrom($socket, 1500) . "'\n";

/* Close it up */
fclose($socket);
fclose($server);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    If a message received is longer than the <parameter>length</parameter>
    parameter, excess bytes may be discarded depending on the type of socket
    the message is received from (such as UDP).
   </para>
  </note>
  <note>
   <para>
    Calls to <function>stream_socket_recvfrom</function> on socket-based
    streams, after calls to buffer-based stream functions (like
    <function>fread</function> or <function>stream_get_line</function>) read
    data directly from the socket and bypass the stream buffer.
    </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <simplelist>
   <member><function>stream_socket_sendto</function></member>
   <member><function>stream_socket_client</function></member>
   <member><function>stream_socket_server</function></member>
  </simplelist>
 </refsect1>

</refentry>
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