title: the output of ftell in php function
body: <p>Here is my code:</p>
  
  <pre><code>&lt;?php
      $url="http://www.sina.com.cn";
      $handle = @fopen($url, "r");
      $len=get_headers($url,true);
      print_r($len);
      echo $len['Content-Length']."\n";
      if ($handle) {
          while (($buffer = fgets($handle,1024)) !== false) {
              echo ftell($handle)."\n";
              fseek($handle,200000,SEEK_CUR);
              echo ftell($handle)."\n";
          }
          if (!feof($handle)) {
              echo "Error: unexpected fgets() fail\n";
          }
          fclose($handle);
      }
  ?&gt;
  </code></pre>
  
  <p>The result is as below:</p>
  
  <pre><code>    Array
  (
      [0] =&gt; HTTP/1.1 200 OK
      [Content-Type] =&gt; text/html
      [Vary] =&gt; Accept-Encoding
      [X-Powered-By] =&gt; shci_v1.03
      [Server] =&gt; nginx
      [Date] =&gt; Thu, 24 Dec 2015 04:03:39 GMT
      [Last-Modified] =&gt; Thu, 24 Dec 2015 04:01:28 GMT
      [Expires] =&gt; Thu, 24 Dec 2015 04:04:39 GMT
      [Cache-Control] =&gt; max-age=60
      [Age] =&gt; 32
      [Content-Length] =&gt; 518264
      [X-Cache] =&gt; HIT from xidan33-99.sina.com.cn
      [Connection] =&gt; close
  )
  518264
  16
  200016
  200058
  400058
  400065
  518264
  </code></pre>
  
  <p>The Content-Length maybe not the same as mine--518264,it will be changed dynamically when you execute the code,it does no matter for the discussion.
  Why the result is not the following?</p>
  
  <pre><code>518264
  1024
  201024
  202048
  402048
  403072
  </code></pre>
  
  <p>please explain the action of file pointer on fgets and ftell and fseek function .                      </p>