I went back to problem, in header I have: extern __declspec(dllexport) boost::thread_specific_ptr<int> Storage; extern __declspec(dllexport) int tls_value_storage = 10; //for test In Src I have: extern __declspec(dllexport) boost::thread_specific_ptr<int> Storage; // Error extern __declspec(dllexport) int tls_value_storage; but here I have error in compiling process, there is ok if there is only declaration without extern (in other case I have error LNK1120: 1 unresolved externalsl). In other project I have: extern __declspec(dllimport) boost::thread_specific_ptr<int> TlxStorage; extern __declspec(dllimport) int tls_value_storage; and it's ok. Integer tls_value_storage is only for testing purpose, it work fine (I can see variable in other project). Thanks in advance.