--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libcxx/include/iosfwd	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,220 @@
+// -*- C++ -*-
+//===--------------------------- iosfwd -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_IOSFWD
+#define _LIBCPP_IOSFWD
+
+/*
+    iosfwd synopsis
+
+namespace std
+{
+
+template<class charT> struct char_traits;
+template<>            struct char_traits<char>;
+template<>            struct char_traits<char8_t>;  // C++20
+template<>            struct char_traits<char16_t>;
+template<>            struct char_traits<char32_t>;
+template<>            struct char_traits<wchar_t>;
+
+template<class T>     class allocator;
+
+class ios_base;
+template <class charT, class traits = char_traits<charT> > class basic_ios;
+
+template <class charT, class traits = char_traits<charT> > class basic_streambuf;
+template <class charT, class traits = char_traits<charT> > class basic_istream;
+template <class charT, class traits = char_traits<charT> > class basic_ostream;
+template <class charT, class traits = char_traits<charT> > class basic_iostream;
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_stringbuf;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_istringstream;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_ostringstream;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_stringstream;
+
+template <class charT, class traits = char_traits<charT> > class basic_filebuf;
+template <class charT, class traits = char_traits<charT> > class basic_ifstream;
+template <class charT, class traits = char_traits<charT> > class basic_ofstream;
+template <class charT, class traits = char_traits<charT> > class basic_fstream;
+
+template <class charT, class traits = char_traits<charT> > class istreambuf_iterator;
+template <class charT, class traits = char_traits<charT> > class ostreambuf_iterator;
+
+typedef basic_ios<char>              ios;
+typedef basic_ios<wchar_t>           wios;
+
+typedef basic_streambuf<char>        streambuf;
+typedef basic_istream<char>          istream;
+typedef basic_ostream<char>          ostream;
+typedef basic_iostream<char>         iostream;
+
+typedef basic_stringbuf<char>        stringbuf;
+typedef basic_istringstream<char>    istringstream;
+typedef basic_ostringstream<char>    ostringstream;
+typedef basic_stringstream<char>     stringstream;
+
+typedef basic_filebuf<char>          filebuf;
+typedef basic_ifstream<char>         ifstream;
+typedef basic_ofstream<char>         ofstream;
+typedef basic_fstream<char>          fstream;
+
+typedef basic_streambuf<wchar_t>     wstreambuf;
+typedef basic_istream<wchar_t>       wistream;
+typedef basic_ostream<wchar_t>       wostream;
+typedef basic_iostream<wchar_t>      wiostream;
+
+typedef basic_stringbuf<wchar_t>     wstringbuf;
+typedef basic_istringstream<wchar_t> wistringstream;
+typedef basic_ostringstream<wchar_t> wostringstream;
+typedef basic_stringstream<wchar_t>  wstringstream;
+
+typedef basic_filebuf<wchar_t>       wfilebuf;
+typedef basic_ifstream<wchar_t>      wifstream;
+typedef basic_ofstream<wchar_t>      wofstream;
+typedef basic_fstream<wchar_t>       wfstream;
+
+template <class state> class fpos;
+typedef fpos<char_traits<char>::state_type>    streampos;
+typedef fpos<char_traits<wchar_t>::state_type> wstreampos;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <wchar.h>  // for mbstate_t
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_TYPE_VIS ios_base;
+
+template<class _CharT>  struct _LIBCPP_TEMPLATE_VIS char_traits;
+template<> struct char_traits<char>;
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+template<> struct char_traits<char8_t>;
+#endif
+template<> struct char_traits<char16_t>;
+template<> struct char_traits<char32_t>;
+template<> struct char_traits<wchar_t>;
+
+template<class _Tp>     class _LIBCPP_TEMPLATE_VIS allocator;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ios;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_streambuf;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_istream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ostream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_iostream;
+
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_stringbuf;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_istringstream;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ostringstream;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_stringstream;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_filebuf;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ifstream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ofstream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_fstream;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS istreambuf_iterator;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS ostreambuf_iterator;
+
+typedef basic_ios<char>              ios;
+typedef basic_ios<wchar_t>           wios;
+
+typedef basic_streambuf<char>        streambuf;
+typedef basic_istream<char>          istream;
+typedef basic_ostream<char>          ostream;
+typedef basic_iostream<char>         iostream;
+
+typedef basic_stringbuf<char>        stringbuf;
+typedef basic_istringstream<char>    istringstream;
+typedef basic_ostringstream<char>    ostringstream;
+typedef basic_stringstream<char>     stringstream;
+
+typedef basic_filebuf<char>          filebuf;
+typedef basic_ifstream<char>         ifstream;
+typedef basic_ofstream<char>         ofstream;
+typedef basic_fstream<char>          fstream;
+
+typedef basic_streambuf<wchar_t>     wstreambuf;
+typedef basic_istream<wchar_t>       wistream;
+typedef basic_ostream<wchar_t>       wostream;
+typedef basic_iostream<wchar_t>      wiostream;
+
+typedef basic_stringbuf<wchar_t>     wstringbuf;
+typedef basic_istringstream<wchar_t> wistringstream;
+typedef basic_ostringstream<wchar_t> wostringstream;
+typedef basic_stringstream<wchar_t>  wstringstream;
+
+typedef basic_filebuf<wchar_t>       wfilebuf;
+typedef basic_ifstream<wchar_t>      wifstream;
+typedef basic_ofstream<wchar_t>      wofstream;
+typedef basic_fstream<wchar_t>       wfstream;
+
+template <class _State>             class _LIBCPP_TEMPLATE_VIS fpos;
+typedef fpos<mbstate_t>    streampos;
+typedef fpos<mbstate_t>    wstreampos;
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+typedef fpos<mbstate_t>    u8streampos;
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+typedef fpos<mbstate_t>    u16streampos;
+typedef fpos<mbstate_t>    u32streampos;
+#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+#if defined(_NEWLIB_VERSION)
+// On newlib, off_t is 'long int'
+typedef long int streamoff;         // for char_traits in <string>
+#else
+typedef long long streamoff;        // for char_traits in <string>
+#endif
+
+template <class _CharT,             // for <stdexcept>
+          class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_string;
+typedef basic_string<char, char_traits<char>, allocator<char> > string;
+typedef basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t> > wstring;
+
+
+// Include other forward declarations here
+template <class _Tp, class _Alloc = allocator<_Tp> >
+class _LIBCPP_TEMPLATE_VIS vector;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP_IOSFWD