title: New VS C++ update is making boost forward declared code un-compilable ! What can you do?
body: <p>These are the new errors I get when I try to use a project that I am building that uses Boost as statically linked libraries. But the very includes alone cry in compilation. Please advice.</p>
  
  <p>Boost Version : 1.68</p>
  
  <p>Visual Studio version (Community) : 15.8.0 , Last updated Aug 14, 2018.</p>
  
  <pre><code>   Severity Code    Description Project File    Line    Suppression State
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   119 
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   119 
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   119 
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp   30  
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   119 
      Error   C4643   Forward declaring 'allocator' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp   30  
      Error   C4643   Forward declaring 'allocator_arg_t' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp 49  
      Error   C4643   Forward declaring 'allocator_arg_t' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp 49  
      Error   C4643   Forward declaring 'basic_istream' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp    47  
      Error   C4643   Forward declaring 'basic_istream' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp    47  
      Error   C4643   Forward declaring 'basic_ostream' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp    44  
      Error   C4643   Forward declaring 'basic_ostream' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp    44  
      Error   C4643   Forward declaring 'basic_string' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp    120 
      Error   C4643   Forward declaring 'basic_string' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp    120 
      Error   C4643   Forward declaring 'basic_string' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp    120 
      Error   C4643   Forward declaring 'basic_string' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp    120 
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp   33  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp   33  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp  43  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp   30  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp   33  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp   33  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp  43  
      Error   C4643   Forward declaring 'bidirectional_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp   30  
      Error   C4643   Forward declaring 'bitset' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp  143 
      Error   C4643   Forward declaring 'bitset' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp  143 
      Error   C4643   Forward declaring 'bitset' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp  143 
      Error   C4643   Forward declaring 'bitset' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp  143 
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 122 
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 122 
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 122 
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp 39  
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp  34  
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 122 
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\container\detail\std_fwd.hpp 39  
      Error   C4643   Forward declaring 'char_traits' in namespace std is not permitted by the C++ Standard.boost-root\boost\interprocess\detail\std_fwd.hpp  34  
      Error   C4643   Forward declaring 'complex' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 127 
      Error   C4643   Forward declaring 'complex' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 127 
      Error   C4643   Forward declaring 'complex' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 127 
      Error   C4643   Forward declaring 'complex' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp 127 
      Error   C4643   Forward declaring 'deque' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   131 
      Error   C4643   Forward declaring 'deque' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   131 
      Error   C4643   Forward declaring 'deque' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   131 
      Error   C4643   Forward declaring 'deque' in namespace std is not permitted by the C++ Standard.boost-root\boost\detail\container_fwd.hpp   131 
      Error   C4643   Forward declaring 'forward_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp 32  
      Error   C4643   Forward declaring 'forward_iterator_tag' in namespace std is not permitted by the C++ Standard.boost-root\boost\move\detail\iterator_traits.hpp 32  
  </code></pre>