How to make c++filt to work for all C++ names?

Question

When I try to demangle some names from standard C++ library like:

$ c++filt _ZNSt8ios_base4InitD1Ev
std::ios_base::Init::~Init()
$ c++filt _ZNSolsEPFRSoS_E
std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))

then it works with many names. However there are some names which cannot be demangled like:

$ c++filt _ZSt4endlIcSt11char_trait
_ZSt4endlIcSt11char_trait
$ c++filt _ZStlsISt11char_traitsIcE
_ZStlsISt11char_traitsIcE

c++filt doesn't seem to succeed on it. Why last two names are not demangled correctly and how to demangle them?