Thousands of people must have done this successfully - but it seems I can't! Just installed Cygwin including gcc on Windows XP, taking all the defaults. #include <iostream> int main( ) { std::cout << "Hello" << std::endl; } $ gcc hello.cpp /cygdrive/c/DOCUME~1/ROBJON~1/LOCALS~1/Temp/ccr1lzvF.o:hello.cpp:(.text+0xd): undefined reference to `std::basic_string< char, std::char_traits<char>, std::allocator<char> >::size() const' /cygdrive/c/DOCUME~1/ROBJON~1/LOCALS~1/Temp/ccr1lzvF.o:hello.cpp:(.text+0x60): undefined reference to `std::basic_string <char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned int) const' What am I doing wrong guys? Thanks All.