hello: I use : windows 7 64bit, vs 2012 , boost 1.5.4 , Win64OpenSSL_Light-1_0_1e. the codes is:

######################## #include #include ########################

When I complie it, the wrong messages is: ########################################## 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_cleanup_all_ex_data referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_num_locks referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_set_locking_callback referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_set_id_callback referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CONF_modules_unload referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _OPENSSL_add_all_algorithms_noconf referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _EVP_cleanup referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _SSL_load_error_strings referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _SSL_library_init referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_reason_error_string referenced in function "public: virtual class std::basic_string __thiscall boost::asio::error::detail::ssl_category::message(int)const " (?message@ssl_category@detail@error@asio@boost@@UBE?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@H@Z) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_free_strings referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_remove_state referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ENGINE_cleanup referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>D:\program\gdnscenter-1.12.2\src\Debug\gtest.exe : fatal error LNK1120: 13 unresolved externals ========== Build: 0 succeeded, 1 failed, 3 up-to-date, 0 skipped ========== ##########################################

the simiar question in stackoverflow :http://stackoverflow.com/questions/9357751/boost-ssl-with-visual-studio-2010....

I use the openssl win64. So, Maybe a bug in asio?

Maybe you don't link the relevant OpenSSL libraries?