title: Get JSON data from many urls via curl_multi
body: <p>Five hours i try to make this code worked:</p>
  
  <pre><code>$url_list = array(
      'https://btc-e.com/api/2/btc_usd/ticker',
      'https://btc-e.com/api/2/btc_eur/ticker',
      'https://btc-e.com/api/2/btc_rur/ticker',
      'https://btc-e.com/api/2/ltc_btc/ticker',
      'https://btc-e.com/api/2/ltc_usd/ticker',
      'https://btc-e.com/api/2/ltc_rur/ticker',
      'https://btc-e.com/api/2/usd_rur/ticker',
      'https://btc-e.com/api/2/eur_usd/ticker',
      'https://btc-e.com/api/2/nmc_btc/ticker',
      'https://btc-e.com/api/2/nvc_btc/ticker',
      'https://btc-e.com/api/2/trc_btc/ticker',
      'https://btc-e.com/api/2/ppc_btc/ticker',
      'https://btc-e.com/api/2/ftc_btc/ticker'
  );
  
  function multi_thread_request($nodes){ 
      $mh = curl_multi_init(); 
      $curl_array = array();
      $res = array();
  
      for($i=0;$i&lt;=12;$i++){
          $curl_array[$i] = curl_init($url_list[$i]); 
          curl_setopt($curl_array[$i], CURLOPT_RETURNTRANSFER, true); 
          curl_multi_add_handle($mh, $curl_array[$i]); 
      } 
      $running = NULL; 
      do { 
          //usleep(10000); 
          curl_multi_exec($mh,$running); 
      } while($running &gt; 0); 
  
  
      for($i=0;$i&lt;=12;$i++){
          $res[$i] = curl_multi_getcontent($curl_array[$i]);
      } 
  
      for($i=0;$i&lt;=12;$i++){ 
          curl_multi_remove_handle($mh, $curl_array[$i]); 
      } 
      curl_multi_close($mh);        
      return $res; 
  } 
  print_r(multi_thread_request($url_list)); 
  </code></pre>
  
  <p>And it always gives me only array with keys, but with no data.
  Where is my error?</p>