Hi, Thanks to Mr Watanabe, it compiled on Windows. Now I am trying to compile on Linux. I was hoping things would be easier because of package managers. The package manager installed headers into /usr/include/boost and libs into /usr/lib/ (found out from YAST) When I try to compile the same examplehttp://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/chat/chat_s...with (c++ -I /usr/include/ chat_server.cpp -o chat_server) I get errors. I guess I should also specify a library on the command line. But which library I should include? The error messages seems not very helpful. It doesn't print the line number of the error, but things like .text+0xb3: chat_server.cpp:(.text+0xb3): undefined reference to `boost::system::get_system_category()' I grepped in lib folder for a name with system, but none from boost. Hopefully, you can show me some directions, Thanks in advance, Best regards, Ozgur (Oscar) Ozturk www.DrOzgur.com +1 (614) 805-4370