title: ACE_SOCK_Dgram::open() and errno
body: <p>I tried to open already opened UDP port and ACE_SOCK_Dgram::open() failed.
  As expected, strace shows that bind() failed and errno is set to EADDRINUSE.</p>
  
  <p>To see what error happen, I used ACE_OS::last_error(), but it's not updated.</p>
  
  <p>I'd like to give informative error to user that the port already in use, instead of some general error.</p>
  
  <p>Bonus question - when ACE_OS::last_error() can be used?</p>
  
  <p>Tnx</p>