Sorry that it's vc++ C:\Program Files\Microsoft Visual Studio 8\VC\include\sstream(513) : error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>' with [ _Elem=char, _Traits=std::char_traits ] C:\Program Files\Microsoft Visual Studio 8\VC\include\ios(151) : see declaration of 'std::basic_ios<_Elem,_Traits>::basic_ios' with [ _Elem=char, _Traits=std::char_traits ] This diagnostic occurred in the compiler generated function 'std::basic_stringstream<_Elem,_Traits,_Alloc>::basic_stringstream(const std::basic_stringstream<_Elem,_Traits,_Alloc> &)' with [ _Elem=char, _Traits=std::char_traits, _Alloc=std::allocator ]