php-doc-en/reference/sockets/functions/socket-recvfrom.xml

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<refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.socket-recvfrom">
 <refnamediv>
  <refname>socket_recvfrom</refname>
  <refpurpose>Receives data from a socket whether or not it is connection-oriented</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>int</type><methodname>socket_recvfrom</methodname>
   <methodparam><type>resource</type><parameter>socket</parameter></methodparam>
   <methodparam><type>string</type><parameter role="reference">buf</parameter></methodparam>
   <methodparam><type>int</type><parameter>len</parameter></methodparam>
   <methodparam><type>int</type><parameter>flags</parameter></methodparam>
   <methodparam><type>string</type><parameter role="reference">name</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter role="reference">port</parameter></methodparam>
  </methodsynopsis>
  <para>
  The <function>socket_recvfrom</function> function receives <parameter>len</paramater>
  bytes of data in <parameter>buf</parameter> from <parameter>name</parameter> on port
  <parameter>port</parameter> (if socket is not of AF_UNIX type) using
  <parameter>socket</parameter>. <function>socket_recvfrom</function> can be used to
  gather data from either a connected or an unconnected socket. Additionally, one or more
  flags can be specified to modify the behaviour of the function.
  </para>
  <para>
  The <parameter>name</parameter> and <parameter>port</parameter> must be passed as a 
  reference. If the socket is not connection-oriented, <parameter>name</parameter> will
  be set to the internet protocol address of the remote host or the path to the UNIX
  socket. If the socket is connection-oriented, <parameter>name</parameter> is &null.
  Additionnally, the <parameter>port</parameter> will contain the port of the
  remote host in the case of a not connection-oriented AF_INET or AF_INET6 socket. 
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>socket</parameter></term>
     <listitem>
      <para>
       The <parameter>socket</parameter> must be a socket resource previously created with socket_create().
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>buf</parameter></term>
     <listitem>
      <para>
       The data received will be fetched to the variable specified with <parameter>buf</parameter>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>len</parameter></term>
     <listitem>
      <para>
       Up to <parameter>len</parameter> bytes will be fetched from remote host.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>flags</parameter></term>
     <listitem>
      <para>
      The following table contains the different flags that can be set using the
      <parameter>flags</parameter> parameter. Use the OR logic operator to use more
      than one flag.
      </para>
      
      <table>
       <title>Available flags</title>
       <tgroup cols="2">
        <thead>
         <row>
          <entry>Flag</entry>
          <entry>Description</entry>
         </row>
        </thead>
        <tbody>
         <row>
          <entry>MSG_OOB</entry>
          <entry>
          Receive out-of-band data.
          </entry>
         </row>
         <row>
          <entry>MSG_PEEK</entry>
          <entry>
          Receive data from the beginning of the receive queue without removing
          it from the queue.
          </entry>
         </row>
         <row>
          <entry>MSG_WAITALL</entry>
          <entry>
          Block until at least <parameter>len</parameter> are received. However,
          if a signal is caught or the remote host disconnects, the function
          may return less data.
          </entry>
         </row>
         <row>
          <entry>MSG_DONTWAIT</entry>
          <entry>
          With this flag set, the function returns even if it would normally have
          blocked.
          </entry>
         </row>
        </tbody>
       </tgroup>
      </table>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>name</parameter></term>
     <listitem>
      <para>
      If the socket is of AF_UNIX type, <parameter>name</parameter> is the path to the 
      file. Else, in the case of non-connection oriented socket <parameter>name</parameter> 
      is the IP address of the remote host and &null if the socket is connection oriented.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>port</parameter></term>
     <listitem>
      <para>
      This argument only applies to AF_INET and AF_INET6 sockets and specifies the 
      remote port from which the data is received. If the socket is connection
      oriented, <parameter>port</parameter> will be &null.
      </para>
     </listitem>
    </varlistentry>
    
   </variablelist>
  </para>
 </refsect1>
 
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   <function>socket_recvfrom</function> returns the number of bytes received
   or -1 if there was an error. The actual error code can be retrieved by 
   calling <function>socket_last_error</function>. This error code may be passed 
   to <function>socket_strerror</function> to get a textual explanation of the
   error.
  </para>
 </refsect1>
                     
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>socket_recvfrom</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
error_reporting(E_ALL | E_STRICT);

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_connect($socket, "127.0.0.1", 1223);

$Ip = "";
socket_recvfrom($socket, $buf, 12, 0, $Ip, $Port);

echo "Received data: $buf";
?>
]]>
    </programlisting>
    <para>
    This will example will initiate a TCP connection to 127.0.0.1 on port 1223
    and print at most 12 characters received from the remote host or block
    until no data is received.
    </para>
   </example>
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>4.3.0</entry>
       <entry>
        <function>socket_recvfrom</function> is now binary safe.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>socket_recv</function></member>
    <member><function>socket_send</function></member>
    <member><function>socket_sendto</function></member>
    <member><function>socket_create</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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