title: Error in websocketpp library and boost in windows Visual Studio 2015
body: <p>I'm trying to compile this simple example <a href="https://github.com/zaphoyd/websocketpp/blob/master/examples/echo_server/echo_server.cpp" rel="nofollow noreferrer">https://github.com/zaphoyd/websocketpp/blob/master/examples/echo_server/echo_server.cpp</a> from the developer github, but I'm getting strange errors outside the code.</p>
  
  <p>I have also tried turning on the /Za option as shown in this post: <a href="https://stackoverflow.com/questions/12764151/vc-2012-and-boost-incompatibility-throw-specifications-in-library-header">VC++ 2012 and Boost incompatibility - `throw()` specifications in library headers</a> but it throws a different error, saying "Threading support unavaliable: it has been explicitly disabled with BOOST_DISABLE_THREADS"</p>
  
  <p>Does someone know how to fix this?
  thanks!</p>
  
  <p>The errors:
  I'm using Visual Studio 2015 in Windows10 x64, 
  <code>C:\websocketpp\websocketpp/transport/base/connection.hpp(187): error C2694: 'const char *websocketpp::transport::error::category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/transport/base/connection.hpp(187): note: see declaration of 'websocketpp::transport::error::category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/transport/iostream/base.hpp(89): error C2694: 'const char *websocketpp::transport::iostream::error::category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/transport/iostream/base.hpp(89): note: see declaration of 'websocketpp::transport::iostream::error::category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/error.hpp(151): error C2694: 'const char *websocketpp::error::category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/error.hpp(151): note: see declaration of 'websocketpp::error::category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/frame.hpp(831): warning C4267: '=': conversion from 'size_t' to 'uint32_t', possible loss of data
  1&gt;C:\websocketpp\websocketpp/extensions/extension.hpp(65): error C2694: 'const char *websocketpp::extensions::error::category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/extensions/extension.hpp(65): note: see declaration of 'websocketpp::extensions::error::category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\local\boost_1_59_0\boost/asio/detail/config.hpp(227): warning C4005: 'BOOST_ASIO_ERROR_CATEGORY_NOEXCEPT': macro redefinition
  1&gt;  C:\local\boost_1_59_0\boost/asio/detail/config.hpp(213): note: see previous definition of 'BOOST_ASIO_ERROR_CATEGORY_NOEXCEPT'
  1&gt;C:\websocketpp\websocketpp/transport/asio/base.hpp(189): error C2694: 'const char *websocketpp::transport::asio::error::category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/transport/asio/base.hpp(189): note: see declaration of 'websocketpp::transport::asio::error::category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/transport/asio/security/base.hpp(109): error C2694: 'const char *websocketpp::transport::asio::socket::socket_category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/transport/asio/security/base.hpp(109): note: see declaration of 'websocketpp::transport::asio::socket::socket_category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/processors/base.hpp(165): error C2694: 'const char *websocketpp::processor::error::processor_category::name(void) const': overriding virtual function has less restrictive exception specification than base class virtual member function 'const char *std::error_category::name(void) noexcept const'
  1&gt;  C:\websocketpp\websocketpp/processors/base.hpp(165): note: see declaration of 'websocketpp::processor::error::processor_category::name'
  1&gt;  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\system_error(167): note: see declaration of 'std::error_category::name'
  1&gt;C:\websocketpp\websocketpp/common/md5.hpp(367): warning C4267: '+=': conversion from 'size_t' to 'websocketpp::md5::md5_word_t', possible loss of data
  1&gt;C:\websocketpp\websocketpp/sha1/sha1.hpp(176): warning C4267: '=': conversion from 'size_t' to 'unsigned int', possible loss of data
  ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
  </code></p>