In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h: In instantiation of ‘bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = Unistring]’:
/usr/include/c++/4.8/bits/stl_tree.h:1321:11:   required from ‘std::pair<std::_Rb_tree_node_base*, std::_Rb_tree_node_base*> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_get_insert_unique_pos(const key_type&) [with _Key = Unistring; _Val = Unistring; _KeyOfValue = std::_Identity<Unistring>; _Compare = std::less<Unistring>; _Alloc = std::allocator<Unistring>; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::key_type = Unistring]’
/usr/include/c++/4.8/bits/stl_tree.h:1374:47:   required from ‘std::pair<std::_Rb_tree_iterator<_Val>, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(_Arg&&) [with _Arg = const Unistring&; _Key = Unistring; _Val = Unistring; _KeyOfValue = std::_Identity<Unistring>; _Compare = std::less<Unistring>; _Alloc = std::allocator<Unistring>]’
/usr/include/c++/4.8/bits/stl_set.h:463:29:   required from ‘std::pair<typename std::_Rb_tree<_Key, _Key, std::_Identity<_Key>, _Compare, typename _Alloc::rebind<_Key>::other>::const_iterator, bool> std::set<_Key, _Compare, _Alloc>::insert(const value_type&) [with _Key = Unistring; _Compare = std::less<Unistring>; _Alloc = std::allocator<Unistring>; typename std::_Rb_tree<_Key, _Key, std::_Identity<_Key>, _Compare, typename _Alloc::rebind<_Key>::other>::const_iterator = std::_Rb_tree_const_iterator<Unistring>; std::set<_Key, _Compare, _Alloc>::value_type = Unistring]’
search.cpp:63:17:   required from here
/usr/include/c++/4.8/bits/stl_function.h:235:20: error: no match for ‘operator<’ (operand types are ‘const Unistring’ and ‘const Unistring’)
       { return __x < __y; }
                    ^
/usr/include/c++/4.8/bits/stl_function.h:235:20: note: candidates are:
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:64:0,
                 from /usr/include/c++/4.8/bits/char_traits.h:39,
                 from /usr/include/c++/4.8/ios:40,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_pair.h:220:5: note: template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)
     operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
     ^
/usr/include/c++/4.8/bits/stl_pair.h:220:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::pair<_T1, _T2>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/4.8/bits/char_traits.h:39,
                 from /usr/include/c++/4.8/ios:40,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_iterator.h:297:5: note: template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)
     operator<(const reverse_iterator<_Iterator>& __x,
     ^
/usr/include/c++/4.8/bits/stl_iterator.h:297:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::reverse_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/4.8/bits/char_traits.h:39,
                 from /usr/include/c++/4.8/ios:40,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_iterator.h:347:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&)
     operator<(const reverse_iterator<_IteratorL>& __x,
     ^
/usr/include/c++/4.8/bits/stl_iterator.h:347:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::reverse_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/4.8/bits/char_traits.h:39,
                 from /usr/include/c++/4.8/ios:40,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_iterator.h:1055:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::move_iterator<_Iterator>&, const std::move_iterator<_IteratorR>&)
     operator<(const move_iterator<_IteratorL>& __x,
     ^
/usr/include/c++/4.8/bits/stl_iterator.h:1055:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::move_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/4.8/bits/char_traits.h:39,
                 from /usr/include/c++/4.8/ios:40,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_iterator.h:1061:5: note: template<class _Iterator> bool std::operator<(const std::move_iterator<_Iterator>&, const std::move_iterator<_Iterator>&)
     operator<(const move_iterator<_Iterator>& __x,
     ^
/usr/include/c++/4.8/bits/stl_iterator.h:1061:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::move_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/string:52:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/basic_string.h:2569:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const std::basic_string<_CharT, _Traits, _Alloc>&)
     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^
/usr/include/c++/4.8/bits/basic_string.h:2569:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::basic_string<_CharT, _Traits, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/string:52:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/basic_string.h:2581:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)
     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^
/usr/include/c++/4.8/bits/basic_string.h:2581:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::basic_string<_CharT, _Traits, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/string:52:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/basic_string.h:2593:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const std::basic_string<_CharT, _Traits, _Alloc>&)
     operator<(const _CharT* __lhs,
     ^
/usr/include/c++/4.8/bits/basic_string.h:2593:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   mismatched types ‘const _CharT*’ and ‘Unistring’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/set:60:0,
                 from search.cpp:6:
/usr/include/c++/4.8/bits/stl_tree.h:914:5: note: template<class _Key, class _Val, class _KeyOfValue, class _Compare, class _Alloc> bool std::operator<(const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&, const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&)
     operator<(const _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>& __x,
     ^
/usr/include/c++/4.8/bits/stl_tree.h:914:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/set:61:0,
                 from search.cpp:6:
/usr/include/c++/4.8/bits/stl_set.h:769:5: note: template<class _Key, class _Compare, class _Alloc> bool std::operator<(const std::set<_Key, _Compare, _Alloc>&, const std::set<_Key, _Compare, _Alloc>&)
     operator<(const set<_Key, _Compare, _Alloc>& __x,
     ^
/usr/include/c++/4.8/bits/stl_set.h:769:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::set<_Key, _Compare, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/set:62:0,
                 from search.cpp:6:
/usr/include/c++/4.8/bits/stl_multiset.h:754:5: note: template<class _Key, class _Compare, class _Alloc> bool std::operator<(const std::multiset<_Key, _Compare, _Alloc>&, const std::multiset<_Key, _Compare, _Alloc>&)
     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
     ^
/usr/include/c++/4.8/bits/stl_multiset.h:754:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::multiset<_Key, _Compare, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/tuple:39:0,
                 from /usr/include/c++/4.8/bits/stl_map.h:63,
                 from /usr/include/c++/4.8/map:61,
                 from search.cpp:7:
/usr/include/c++/4.8/array:238:5: note: template<class _Tp, unsigned int _Nm> bool std::operator<(const std::array<_Tp, _Nm>&, const std::array<_Tp, _Nm>&)
     operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
     ^
/usr/include/c++/4.8/array:238:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::array<_Tp, _Nm>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/bits/stl_map.h:63:0,
                 from /usr/include/c++/4.8/map:61,
                 from search.cpp:7:
/usr/include/c++/4.8/tuple:822:5: note: template<class ... _TElements, class ... _UElements> constexpr bool std::operator<(const std::tuple<_Args1 ...>&, const std::tuple<_Args2 ...>&)
     operator<(const tuple<_TElements...>& __t,
     ^
/usr/include/c++/4.8/tuple:822:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::tuple<_Args1 ...>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/map:61:0,
                 from search.cpp:7:
/usr/include/c++/4.8/bits/stl_map.h:978:5: note: template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator<(const std::map<_Key, _Tp, _Compare, _Alloc>&, const std::map<_Key, _Tp, _Compare, _Alloc>&)
     operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
     ^
/usr/include/c++/4.8/bits/stl_map.h:978:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::map<_Key, _Tp, _Compare, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/map:62:0,
                 from search.cpp:7:
/usr/include/c++/4.8/bits/stl_multimap.h:880:5: note: template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator<(const std::multimap<_Key, _Tp, _Compare, _Alloc>&, const std::multimap<_Key, _Tp, _Compare, _Alloc>&)
     operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
     ^
/usr/include/c++/4.8/bits/stl_multimap.h:880:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::multimap<_Key, _Tp, _Compare, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/include/c++/4.8/vector:64:0,
                 from ../../include/string/unistring.h:5,
                 from search.cpp:8:
/usr/include/c++/4.8/bits/stl_vector.h:1420:5: note: template<class _Tp, class _Alloc> bool std::operator<(const std::vector<_Tp, _Alloc>&, const std::vector<_Tp, _Alloc>&)
     operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
     ^
/usr/include/c++/4.8/bits/stl_vector.h:1420:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/4.8/string:48:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from search.cpp:4:
/usr/include/c++/4.8/bits/stl_function.h:235:20: note:   ‘const Unistring’ is not derived from ‘const std::vector<_Tp, _Alloc>’
       { return __x < __y; }
                    ^