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<div id="function.stream-socket-recvfrom" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">stream_socket_recvfrom</h1>
  <p class="verinfo">(PHP 5, PHP 7, PHP 8)</p><p class="refpurpose"><span class="refname">stream_socket_recvfrom</span> &mdash; <span class="dc-title">Receives data from a socket, connected or not</span></p>

 </div>
 <div class="refsect1 description" id="refsect1-function.stream-socket-recvfrom-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>stream_socket_recvfrom</strong></span>(<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="methodparam"><span class="type"><a href="language.types.resource.php" class="type resource">resource</a></span> <code class="parameter">$socket</code></span>,<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$length</code></span>,<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$flags</code><span class="initializer"> = 0</span></span>,<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="methodparam"><span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="language.types.string.php" class="type string">string</a></span></span> <code class="parameter reference">&$address</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.null">null</a></code></strong></span></span><br>): <span class="type"><span class="type"><a href="language.types.string.php" class="type string">string</a></span>|<span class="type"><a href="language.types.singleton.php" class="type false">false</a></span></span></div>

  <p class="para rdfs-comment">
   <span class="function"><strong>stream_socket_recvfrom()</strong></span> accepts
   data from a remote socket up to <code class="parameter">length</code> bytes.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.stream-socket-recvfrom-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>
    
     <dt><code class="parameter">socket</code></dt>
     <dd>
      <p class="para">
       The remote socket.
      </p>
     </dd>
    
    
     <dt><code class="parameter">length</code></dt>
     <dd>
      <p class="para">
       The number of bytes to receive from the <code class="parameter">socket</code>.
      </p>
     </dd>
    
    
     <dt><code class="parameter">flags</code></dt>
     <dd>
      <p class="para">
       The value of <code class="parameter">flags</code> can be any combination
       of the following:
       <table class="doctable table">
        <caption><strong>Possible values for <code class="parameter">flags</code></strong></caption>
        
         <tbody class="tbody">
          <tr>
           <td><strong><code><a href="stream.constants.php#constant.stream-oob">STREAM_OOB</a></code></strong></td>
           <td>
            Process OOB (<code class="literal">out-of-band</code>) data.
           </td>
          </tr>

          <tr>
           <td><strong><code><a href="stream.constants.php#constant.stream-peek">STREAM_PEEK</a></code></strong></td>
           <td>
            Retrieve data from the socket, but do not consume the buffer.
            Subsequent calls to <span class="function"><a href="function.fread.php" class="function">fread()</a></span> or
            <span class="function"><strong>stream_socket_recvfrom()</strong></span> will see
            the same data.
           </td>
          </tr>

         </tbody>
        
       </table>

      </p>
     </dd>
    
    
     <dt><code class="parameter">address</code></dt>
     <dd>
      <p class="para">
       If <code class="parameter">address</code> is provided it will be populated with
       the address of the remote socket.
      </p>
     </dd>
    
   </dl>
  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.stream-socket-recvfrom-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns the read data, as a string, 或者在失败时返回 <strong><code><a href="reserved.constants.php#constant.false">false</a></code></strong>.
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.stream-socket-recvfrom-examples">
  <h3 class="title">示例</h3>
  <p class="para">
   <div class="example" id="example-1">
    <p><strong>示例 #1 <span class="function"><strong>stream_socket_recvfrom()</strong></span> example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">/* Open a server socket to port 1234 on localhost */<br /></span><span style="color: #0000BB">$server </span><span style="color: #007700">= </span><span style="color: #0000BB">stream_socket_server</span><span style="color: #007700">(</span><span style="color: #DD0000">'tcp://127.0.0.1:1234'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* Accept a connection */<br /></span><span style="color: #0000BB">$socket </span><span style="color: #007700">= </span><span style="color: #0000BB">stream_socket_accept</span><span style="color: #007700">(</span><span style="color: #0000BB">$server</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* Grab a packet (1500 is a typical MTU size) of OOB data */<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Received Out-Of-Band: '" </span><span style="color: #007700">. </span><span style="color: #0000BB">stream_socket_recvfrom</span><span style="color: #007700">(</span><span style="color: #0000BB">$socket</span><span style="color: #007700">, </span><span style="color: #0000BB">1500</span><span style="color: #007700">, </span><span style="color: #0000BB">STREAM_OOB</span><span style="color: #007700">) . </span><span style="color: #DD0000">"'\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* Take a peek at the normal in-band data, but don't consume it. */<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Data: '" </span><span style="color: #007700">. </span><span style="color: #0000BB">stream_socket_recvfrom</span><span style="color: #007700">(</span><span style="color: #0000BB">$socket</span><span style="color: #007700">, </span><span style="color: #0000BB">1500</span><span style="color: #007700">, </span><span style="color: #0000BB">STREAM_PEEK</span><span style="color: #007700">) . </span><span style="color: #DD0000">"'\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* Get the exact same packet again, but remove it from the buffer this time. */<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Data: '" </span><span style="color: #007700">. </span><span style="color: #0000BB">stream_socket_recvfrom</span><span style="color: #007700">(</span><span style="color: #0000BB">$socket</span><span style="color: #007700">, </span><span style="color: #0000BB">1500</span><span style="color: #007700">) . </span><span style="color: #DD0000">"'\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* Close it up */<br /></span><span style="color: #0000BB">fclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$socket</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">fclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$server</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span></span></code></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 notes" id="refsect1-function.stream-socket-recvfrom-notes">
  <h3 class="title">注释</h3>
  <blockquote class="note"><p><strong class="note">注意</strong>: 
   <p class="para">
    If a message received is longer than the <code class="parameter">length</code>
    parameter, excess bytes may be discarded depending on the type of socket
    the message is received from (such as UDP).
   </p>
  </p></blockquote>
  <blockquote class="note"><p><strong class="note">注意</strong>: 
   <p class="para">
    Calls to <span class="function"><strong>stream_socket_recvfrom()</strong></span> on socket-based
    streams, after calls to buffer-based stream functions (like
    <span class="function"><a href="function.fread.php" class="function">fread()</a></span> or <span class="function"><a href="function.stream-get-line.php" class="function">stream_get_line()</a></span>) read
    data directly from the socket and bypass the stream buffer.
    </p>
  </p></blockquote>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.stream-socket-recvfrom-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li><span class="function"><a href="function.stream-socket-sendto.php" class="function" rel="rdfs-seeAlso">stream_socket_sendto()</a> - Sends a message to a socket, whether it is connected or not</span></li>
   <li><span class="function"><a href="function.stream-socket-client.php" class="function" rel="rdfs-seeAlso">stream_socket_client()</a> - Open Internet or Unix domain socket connection</span></li>
   <li><span class="function"><a href="function.stream-socket-server.php" class="function" rel="rdfs-seeAlso">stream_socket_server()</a> - 创建 Internet 或 Unix 域服务器套接字</span></li>
  </ul>
 </div>


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