tmark@… — Tue, 23 Feb 2016 11:35:16 GMT

After further analysis we've discovered that the optimizer does not remove the tests, it alters the comparison of (ec == enumerated value). If one replaces the "ec" with "ec.value()" in the expressions, such that you are explicitly comparing the interger error value the code works correctly when optimized:

     :
    // Retry operation if interrupted by signal.
    if (ec.value() == boost::asio::error::interrupted)
      continue;
    // Check if we need to run the operation again.
    if (ec.value() == boost::asio::error::would_block
        || ec.value() == boost::asio::error::try_again)
      return false;
     :

Alternatively, adding an inline operator:

      inline friend bool operator==( const error_code & lhs,
                                     const int & rhs ) BOOST_SYSTEM_NOEXCEPT
      {
        return lhs.m_val == rhs;
      }

to error_code class also cures the issue.

tomasz(at)isc(dot)org — Fri, 19 Aug 2016 08:00:27 GMT

I confirm the issue still manifests itself on libboost 1.58 when compiled using g++ 5.4.0-6ubuntu1~16.04.2. That's the stock version available in Ubuntu 16.04

Boost C++ Libraries: Ticket #11989: gcc 5.3 optimizer mangles non_blocking_recvfrom