title: Xcode 9 iOS 11 BoringSSL SSL_ERROR_ZERO_RETURN
body: <p>I have a simple program HelloWorld running on iOS. The same code has been running fine for a long time. Recently, I notice that I get the below BoringSSL error when the program runs on my ipad connected to Xcode 9 on my Macbook. I don't see this error when I run the program in simulator. The iOS is 11.2. Xcode is 9.2.</p>
  
  <p>My code has no reference to BoringSSL. However, it does use NSMutableURLRequest to make https call to a server. The call works fine and everything seems to work fine except the BoringSSL messages.</p>
  
  <p>Is there a way the I can debug why the message comes up? HellowWorld[466:85961], what do those 2 numbers mean? </p>
  
  <p>What does the message mean and how to avoid it?</p>
  
  <pre><code>2017-12-13 15:41:13.486047-0500 HellowWorld[466:85961] [BoringSSL] Function boringssl_session_errorlog: line 2871 [boringssl_session_read] SSL_ERROR_ZERO_RETURN(6): operation failed because the connection was cleanly shut down with a close_notify alert
  2017-12-13 15:41:13.486363-0500 HellowWorld[466:85961] [BoringSSL] Function boringssl_session_errorlog: line 2871 [boringssl_session_read] SSL_ERROR_ZERO_RETURN(6): operation failed because the connection was cleanly shut down with a close_notify alert
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/cCLOV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cCLOV.png" alt="Screenshot added"></a></p>