namespace TEST{ typedef std::basic_string string; } boost\boost\serialization\access.hpp(106) : error C2039: 'serialize' : is not a member of 'std::basic_string<_Elem,_Traits,_Ax>' with [ _Elem=char, _Traits=std::char_traits<char>, _Ax= TEST_Allocator <char> ] Looking in the string.h template inline void serialize( Archive & ar, STD::basic_string & t, const unsigned int file_version what is strange is when I look at my definition of basic_string in the file xstring of .NET 2003 I found template, class _Ax = allocator<_Elem> > class basic_string : public _String_val<_Elem, _Ax> Any idea ? - VDB - "LNK2019: unresolved external symbol" Olivier Vanden Bos MSN#TheVdeub@hotmail.com AI Programmer UBISOFT Montreal