Maybe this is a stupid problem , but I really don't konw how to find the right way. My compile environment is WinXP, Msys , MinGw , G++ 3.4.2, Boost 1.33.1, asio_0_3_7, bjam 3.1.13. I have already copy the header files of boost and asio into mingw/include I write the helloWorld.cpp follow the tutorial. #include <iostream> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> int main() { boost::asio::io_service io; boost::asio::deadline_timer t(io, boost::posix_time::seconds(5)); t.wait(); std::cout << "Hello, world!\n"; return 0; } I write Jamroot as follow: exe hello : hello.cpp ; then I compile it in Msys, but link wrong happened(wrong messages see the end of this Email). Would you please help me to solve this problem . Thank you for(;;){} //forever $ bjam ...found 11 targets... ...updating 5 targets... MkDir1 bin MkDir1 bin\gcc MkDir1 bin\gcc\debug gcc.compile.c++ bin\gcc\debug\hello.o In file included from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/win_local_free_on_block_exit.hpp:27, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/system_exception.hpp:33, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/win_mutex.hpp:26, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/mutex.hpp:27, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/service_registry.hpp:25, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/io_service.hpp:32, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/basic_io_object.hpp:20, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/basic_socket.hpp:20, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/basic_datagram_socket.hpp:25, from e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio.hpp:18, from hello.cpp:11: e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/socket_types.hpp:31:5: warning: #warning Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/detail/socket_types.hpp:32:5: warning: #warning Assuming _WIN32_WINNT=0x0500 (i.e. Windows 2000 target) hello.cpp:24:2: warning: no newline at end of file gcc.link bin\gcc\debug\hello.exe bin\gcc\debug\hello.o: In function `ZN5boost4asio6detail31reactive_deadline_timer_serviceINS0_11time_traitsINS_10posix_time5ptimeEEENS1_14select_reactorILb1EEEE16shutdown_serviceEv':e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail12winsock_initILi2ELi0EE7do_initC1Ev[boost::asio::detail::winsock_init<2, 0>::do_init::do_init()]+0x1f): undefined reference to `WSAStartup@8' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops6selectEiP6fd_setS4_S4_P7timeval[boost::asio::detail::socket_ops::select(int, fd_set*, fd_set*, fd_set*, timeval*)]+0xc9): undefined reference to `select@20' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops13error_wrapperIiEET_S4_[int boost::asio::detail::socket_ops::error_wrapper<int>(int)]+0x8): undefined reference to `WSAGetLastError@0' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops9set_errorEi[boost::asio::detail::socket_ops::set_error(int)]+0x17): undefined reference to `WSASetLastError@4' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail12winsock_initILi2ELi0EE7do_initD1Ev[boost::asio::detail::winsock_init<2, 0>::do_init::~do_init()]+0x7): undefined reference to `WSACleanup@0' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops5closeEj[boost::asio::detail::socket_ops::close(unsigned int)]+0x19): undefined reference to `closesocket@4' bin\gcc\debug\hello.o: In function `main':e:/job/word-online/source/cpp/hello.cpp:15: undefined reference to `inet_addr@4' :e:/job/word-online/source/cpp/hello.cpp:23: undefined reference to `getsockname@12' bin\gcc\debug\hello.o: In function `ZN5boost4asio6detail31reactive_deadline_timer_serviceINS0_11time_traitsINS_10posix_time5ptimeEEENS1_14select_reactorILb1EEEE16shutdown_serviceEv':e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../.. o `closesocket@4' bin\gcc\debug\hello.o: In function `main':e:/job/word-online/source/cpp/hello.cpp:15: undefined reference to `inet_addr@4' :e:/job/word-online/source/cpp/hello.cpp:23: undefined reference to `getsockname@12' bin\gcc\debug\hello.o: In function `ZN5boost4asio6detail31reactive_deadline_timer_serviceINS0_11time_traitsINS_10posix_time5ptimeEEENS1_14select_reactorILb1EEEE16shutdown_serviceEv':e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops5ioctlEjlPm[boost::asio::detail::socket_ops::ioctl(unsigned int, long, unsigned long*)]+0x27): undefined reference to `ioctlsocket@12' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops6acceptEjP8sockaddrPi[boost::asio::detail::socket_ops::accept(unsigned int, sockaddr*, int*)]+0x27): undefined reference to `accept@12' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops13error_wrapperIjEET_S4_[unsigned int boost::asio::detail::socket_ops::error_wrapper<unsigned int>(unsigned int)]+0x8): undefined reference to `WSAGetLastError@0' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops7connectEjPK8sockaddri[boost::asio::detail::socket_ops::connect(unsigned int, sockaddr const*, int)]+0x27): undefined reference to `connect@12' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops6listenEji[boost::asio::detail::socket_ops::listen(unsigned int, int)]+0x20): undefined reference to `listen@8' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops4bindEjPK8sockaddri[boost::asio::detail::socket_ops::bind(unsigned int, sockaddr const*, int)]+0x27): undefined reference to `bind@12' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops10setsockoptEjiiPKvj[boost::asio::detail::socket_ops::setsockopt(unsigned int, int, int, void const*, unsigned int)]+0x35): undefined reference to `setsockopt@20' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops9get_errorEv[boost::asio::detail::socket_ops::get_error()]+0x7): undefined reference to `WSAGetLastError@0' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops6socketEiii[boost::asio::detail::socket_ops::socket(int, int, int)]+0x3f): undefined reference to `WSASocketA@24' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops4recvEjP7_WSABUFji[boost::asio::detail::socket_ops::recv(unsigned int, _WSABUF*, unsigned int, int)]+0x58): undefined reference to `WSARecv@28' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZNK5boost4asio6detail14fd_set_adapter6is_setEj[boost::asio::detail::fd_set_adapter::is_set(unsigned int) const]+0x14): undefined reference to `__WSAFDIsSet@8' :e:/program/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../../include/boost/asio/deadline_timer_service.hpp:(.text$_ZN5boost4asio6detail10socket_ops4sendEjPK7_WSABUFji[boost::asio::detail::socket_ops::send(unsigned int, _WSABUF const*, unsigned int, int)]+0x58): undefined reference to `WSASend@28' collect2: ld returned 1 exit status "g++" -o "bin\gcc\debug\hello.exe" -Wl,--start-group "bin\gcc\debug\hello.o" -Wl,--end-group -g ...failed gcc.link bin\gcc\debug\hello.exe... ...failed updating 1 target... ...updated 4 targets... -- I'm Earth-Man. 我是地球人. --zsp(张沈鹏)