coroutine

coroutine

// -*- C++ -*-
//===----------------------------- coroutine -----------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_EXPERIMENTAL_COROUTINE
#define _LIBCPP_EXPERIMENTAL_COROUTINE

/**
    experimental/coroutine synopsis

// C++next

namespace std {
namespace experimental {
inline namespace coroutines_v1 {

  // 18.11.1 coroutine traits
template <typename R, typename... ArgTypes>
class coroutine_traits;
// 18.11.2 coroutine handle
template <typename Promise = void>
class coroutine_handle;
// 18.11.2.7 comparison operators:
bool operator==(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
bool operator!=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
bool operator<(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
bool operator<=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
bool operator>=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
bool operator>(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
// 18.11.3 trivial awaitables
struct suspend_never;
struct suspend_always;
// 18.11.2.8 hash support:
template <class T> struct hash;
template <class P> struct hash<coroutine_handle<P>>;

} // namespace coroutines_v1
} // namespace experimental
} // namespace std

 */

// -*- C++ -*-
//===--------------------------- __config ---------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_EXPERIMENTAL_CONFIG
#define _LIBCPP_EXPERIMENTAL_CONFIG

// -*- C++ -*-
//===--------------------------- __config ---------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_CONFIG
#define _LIBCPP_CONFIG

#if defined(_MSC_VER) && !defined(__clang__)
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#endif
#endif

#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#pragma GCC system_header
#endif

#ifdef __cplusplus

#ifdef __GNUC__
#define _GNUC_VER (__GNUC__ * 100 + __GNUC_MINOR__)
// The _GNUC_VER_NEW macro better represents the new GCC versioning scheme
// introduced in GCC 5.0.
#define _GNUC_VER_NEW (_GNUC_VER * 10 + __GNUC_PATCHLEVEL__)
#else
#define _GNUC_VER 0
#define _GNUC_VER_NEW 0
#endif

#define _LIBCPP_VERSION 6000

#ifndef _LIBCPP_ABI_VERSION
#define _LIBCPP_ABI_VERSION 1
#endif

#if defined(__ELF__)
#define _LIBCPP_OBJECT_FORMAT_ELF   1
#elif defined(__MACH__)
#define _LIBCPP_OBJECT_FORMAT_MACHO 1
#elif defined(_WIN32)
#define _LIBCPP_OBJECT_FORMAT_COFF  1
#else
#error Unknown object file format
#endif

#if defined(_LIBCPP_ABI_UNSTABLE) || _LIBCPP_ABI_VERSION >= 2
// Change short string representation so that string data starts at offset 0,
// improving its alignment in some cases.
#define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
// Fix deque iterator type in order to support incomplete types.
#define _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
// Fix undefined behavior in how std::list stores its linked nodes.
#define _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
// Fix undefined behavior in  how __tree stores its end and parent nodes.
#define _LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB
// Fix undefined behavior in how __hash_table stores its pointer types.
#define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
#define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
#define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
// Don't use a nullptr_t simulation type in C++03 instead using C++11 nullptr
// provided under the alternate keyword __nullptr, which changes the mangling
// of nullptr_t. This option is ABI incompatible with GCC in C++03 mode.
#define _LIBCPP_ABI_ALWAYS_USE_CXX11_NULLPTR
// Define the `pointer_safety` enum as a C++11 strongly typed enumeration
// instead of as a class simulating an enum. If this option is enabled
// `pointer_safety` and `get_pointer_safety()` will no longer be available
// in C++03.
#define _LIBCPP_ABI_POINTER_SAFETY_ENUM_TYPE
// Define a key function for `bad_function_call` in the library, to centralize
// its vtable and typeinfo to libc++ rather than having all other libraries
// using that class define their own copies.
#define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION

// Enable optimized version of __do_get_(un)signed which avoids redundant copies.
#define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
#elif _LIBCPP_ABI_VERSION == 1
#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
// Enable compiling copies of now inline methods into the dylib to support
// applications compiled against older libraries. This is unnecessary with
// COFF dllexport semantics, since dllexport forces a non-inline definition
// of inline functions to be emitted anyway. Our own non-inline copy would
// conflict with the dllexport-emitted copy, so we disable it.
#define _LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS
#endif
// Feature macros for disabling pre ABI v1 features. All of these options
// are deprecated.
#if defined(__FreeBSD__)
#define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
#endif
#endif

#ifdef _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
#error "_LIBCPP_TRIVIAL_PAIR_COPY_CTOR" is no longer supported. \
       use _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR instead
#endif

#define _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_X##_LIBCPP_Y
#define _LIBCPP_CONCAT(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y)

#define _LIBCPP_NAMESPACE _LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION)

#if __cplusplus < 201103L
#define _LIBCPP_CXX03_LANG
#endif

#ifndef __has_attribute
#define __has_attribute(__x) 0
#endif
#ifndef __has_builtin
#define __has_builtin(__x) 0
#endif
#ifndef __has_extension
#define __has_extension(__x) 0
#endif
#ifndef __has_feature
#define __has_feature(__x) 0
#endif
// '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
// the compiler and '1' otherwise.
#ifndef __is_identifier
#define __is_identifier(__x) 1
#endif
#ifndef __has_declspec_attribute
#define __has_declspec_attribute(__x) 0
#endif

#define __has_keyword(__x) !(__is_identifier(__x))

#ifdef __has_include
#define __libcpp_has_include(__x) __has_include(__x)
#else
#define __libcpp_has_include(__x) 0
#endif

#if defined(__clang__)
#define _LIBCPP_COMPILER_CLANG
# ifndef __apple_build_version__
#   define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
# endif
#elif defined(__GNUC__)
#define _LIBCPP_COMPILER_GCC
#elif defined(_MSC_VER)
#define _LIBCPP_COMPILER_MSVC
#elif defined(__IBMCPP__)
#define _LIBCPP_COMPILER_IBM
#endif

#ifndef _LIBCPP_CLANG_VER
#define _LIBCPP_CLANG_VER 0
#endif

// FIXME: ABI detection should be done via compiler builtin macros. This
// is just a placeholder until Clang implements such macros. For now assume
// that Windows compilers pretending to be MSVC++ target the microsoft ABI.
#if defined(_WIN32) && defined(_MSC_VER)
# define _LIBCPP_ABI_MICROSOFT
#else
# define _LIBCPP_ABI_ITANIUM
#endif

// Need to detect which libc we're using if we're on Linux.
#if defined(__linux__)
#include <features.h>
#if !defined(__GLIBC_PREREQ)
#define __GLIBC_PREREQ(a, b) 0
#endif // !defined(__GLIBC_PREREQ)
#endif // defined(__linux__)

#ifdef __LITTLE_ENDIAN__
#if __LITTLE_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 1
#define _LIBCPP_BIG_ENDIAN    0
#endif  // __LITTLE_ENDIAN__
#endif  // __LITTLE_ENDIAN__

#ifdef __BIG_ENDIAN__
#if __BIG_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 0
#define _LIBCPP_BIG_ENDIAN    1
#endif  // __BIG_ENDIAN__
#endif  // __BIG_ENDIAN__

#ifdef __BYTE_ORDER__
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 1
#define _LIBCPP_BIG_ENDIAN 0
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 0
#define _LIBCPP_BIG_ENDIAN 1
#endif // __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#endif // __BYTE_ORDER__

#ifdef __FreeBSD__
# include <sys/endian.h>
#  if _BYTE_ORDER == _LITTLE_ENDIAN
#   define _LIBCPP_LITTLE_ENDIAN 1
#   define _LIBCPP_BIG_ENDIAN    0
# else  // _BYTE_ORDER == _LITTLE_ENDIAN
#   define _LIBCPP_LITTLE_ENDIAN 0
#   define _LIBCPP_BIG_ENDIAN    1
# endif  // _BYTE_ORDER == _LITTLE_ENDIAN
# ifndef __LONG_LONG_SUPPORTED
#  define _LIBCPP_HAS_NO_LONG_LONG
# endif  // __LONG_LONG_SUPPORTED
#endif  // __FreeBSD__

#ifdef __NetBSD__
# include <sys/endian.h>
#  if _BYTE_ORDER == _LITTLE_ENDIAN
#   define _LIBCPP_LITTLE_ENDIAN 1
#   define _LIBCPP_BIG_ENDIAN    0
# else  // _BYTE_ORDER == _LITTLE_ENDIAN
#   define _LIBCPP_LITTLE_ENDIAN 0
#   define _LIBCPP_BIG_ENDIAN    1
# endif  // _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_HAS_QUICK_EXIT
#endif  // __NetBSD__

#if defined(_WIN32)
#  define _LIBCPP_WIN32API
#  define _LIBCPP_LITTLE_ENDIAN 1
#  define _LIBCPP_BIG_ENDIAN    0
#  define _LIBCPP_SHORT_WCHAR   1
// Both MinGW and native MSVC provide a "MSVC"-like enviroment
#  define _LIBCPP_MSVCRT_LIKE
// If mingw not explicitly detected, assume using MS C runtime only if
// a MS compatibility version is specified.
#  if defined(_MSC_VER) && !defined(__MINGW32__)
#    define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
#  endif
#  if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
#    define _LIBCPP_HAS_BITSCAN64
#  endif
# if defined(_LIBCPP_MSVCRT)
#   define _LIBCPP_HAS_QUICK_EXIT
# endif

// Some CRT APIs are unavailable to store apps
#if defined(WINAPI_FAMILY)
#include <winapifamily.h>
#if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) &&                      \
    (!defined(WINAPI_PARTITION_SYSTEM) ||                                      \
     !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_SYSTEM))
#define _LIBCPP_WINDOWS_STORE_APP
#endif
#endif
#endif // defined(_WIN32)

#ifdef __sun__
# include <sys/isa_defs.h>
# ifdef _LITTLE_ENDIAN
#   define _LIBCPP_LITTLE_ENDIAN 1
#   define _LIBCPP_BIG_ENDIAN    0
# else
#   define _LIBCPP_LITTLE_ENDIAN 0
#   define _LIBCPP_BIG_ENDIAN    1
# endif
#endif // __sun__

#if defined(__CloudABI__)
  // Certain architectures provide arc4random(). Prefer using
  // arc4random() over /dev/{u,}random to make it possible to obtain
  // random data even when using sandboxing mechanisms such as chroots,
  // Capsicum, etc.
# define _LIBCPP_USING_ARC4_RANDOM
#elif defined(__native_client__)
  // NaCl's sandbox (which PNaCl also runs in) doesn't allow filesystem access,
  // including accesses to the special files under /dev. C++11's
  // std::random_device is instead exposed through a NaCl syscall.
# define _LIBCPP_USING_NACL_RANDOM
#elif defined(_LIBCPP_WIN32API)
# define _LIBCPP_USING_WIN32_RANDOM
#else
# define _LIBCPP_USING_DEV_RANDOM
#endif

#if !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)
# include <endian.h>
# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define _LIBCPP_LITTLE_ENDIAN 1
#  define _LIBCPP_BIG_ENDIAN    0
# elif __BYTE_ORDER == __BIG_ENDIAN
#  define _LIBCPP_LITTLE_ENDIAN 0
#  define _LIBCPP_BIG_ENDIAN    1
# else  // __BYTE_ORDER == __BIG_ENDIAN
#  error unable to determine endian
# endif
#endif  // !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)

#if __has_attribute(__no_sanitize__) && !defined(_LIBCPP_COMPILER_GCC)
#define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
#else
#define _LIBCPP_NO_CFI
#endif

#if defined(_LIBCPP_COMPILER_CLANG)

// _LIBCPP_ALTERNATE_STRING_LAYOUT is an old name for
// _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT left here for backward compatibility.
#if (defined(__APPLE__) && !defined(__i386__) && !defined(__x86_64__) &&       \
     (!defined(__arm__) || __ARM_ARCH_7K__ >= 2)) ||                           \
    defined(_LIBCPP_ALTERNATE_STRING_LAYOUT)
#define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
#endif

#if __has_feature(cxx_alignas)
#  define _ALIGNAS_TYPE(x) alignas(x)
#  define _ALIGNAS(x) alignas(x)
#else
#  define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
#  define _ALIGNAS(x) __attribute__((__aligned__(x)))
#endif

#if __cplusplus < 201103L
typedef __char16_t char16_t;
typedef __char32_t char32_t;
#endif

#if !(__has_feature(cxx_exceptions)) && !defined(_LIBCPP_NO_EXCEPTIONS)
#define _LIBCPP_NO_EXCEPTIONS
#endif

#if !(__has_feature(cxx_rtti)) && !defined(_LIBCPP_NO_RTTI)
#define _LIBCPP_NO_RTTI
#endif

#if !(__has_feature(cxx_strong_enums))
#define _LIBCPP_HAS_NO_STRONG_ENUMS
#endif

#if !(__has_feature(cxx_decltype))
#define _LIBCPP_HAS_NO_DECLTYPE
#endif

#if __has_feature(cxx_attributes)
#  define _LIBCPP_NORETURN [[noreturn]]
#else
#  define _LIBCPP_NORETURN __attribute__ ((noreturn))
#endif

#if !(__has_feature(cxx_lambdas))
#define _LIBCPP_HAS_NO_LAMBDAS
#endif

#if !(__has_feature(cxx_nullptr))
# if (__has_extension(cxx_nullptr) || __has_keyword(__nullptr)) && defined(_LIBCPP_ABI_ALWAYS_USE_CXX11_NULLPTR)
#   define nullptr __nullptr
# else
#   define _LIBCPP_HAS_NO_NULLPTR
# endif
#endif

#if !(__has_feature(cxx_rvalue_references))
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#endif

#if !(__has_feature(cxx_auto_type))
#define _LIBCPP_HAS_NO_AUTO_TYPE
#endif

#if !(__has_feature(cxx_variadic_templates))
#define _LIBCPP_HAS_NO_VARIADICS
#endif

#if !(__has_feature(cxx_generalized_initializers))
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#endif

#if __has_feature(is_base_of)
#  define _LIBCPP_HAS_IS_BASE_OF
#endif

#if __has_feature(is_final)
#  define _LIBCPP_HAS_IS_FINAL
#endif

// Objective-C++ features (opt-in)
#if __has_feature(objc_arc)
#define _LIBCPP_HAS_OBJC_ARC
#endif

#if __has_feature(objc_arc_weak)
#define _LIBCPP_HAS_OBJC_ARC_WEAK
#endif

#if !(__has_feature(cxx_constexpr))
#define _LIBCPP_HAS_NO_CONSTEXPR
#endif

#if !(__has_feature(cxx_relaxed_constexpr))
#define _LIBCPP_HAS_NO_CXX14_CONSTEXPR
#endif

#if !(__has_feature(cxx_variable_templates))
#define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES
#endif

#if __ISO_C_VISIBLE >= 2011 || __cplusplus >= 201103L
#if defined(__FreeBSD__)
#define _LIBCPP_HAS_QUICK_EXIT
#define _LIBCPP_HAS_C11_FEATURES
#elif defined(__Fuchsia__)
#define _LIBCPP_HAS_QUICK_EXIT
#define _LIBCPP_HAS_C11_FEATURES
#elif defined(__linux__)
#if !defined(_LIBCPP_HAS_MUSL_LIBC)
#if __GLIBC_PREREQ(2, 15) || defined(__BIONIC__)
#define _LIBCPP_HAS_QUICK_EXIT
#endif
#if __GLIBC_PREREQ(2, 17)
#define _LIBCPP_HAS_C11_FEATURES
#endif
#else // defined(_LIBCPP_HAS_MUSL_LIBC)
#define _LIBCPP_HAS_QUICK_EXIT
#define _LIBCPP_HAS_C11_FEATURES
#endif
#endif // __linux__
#endif

#if !(__has_feature(cxx_noexcept))
#define _LIBCPP_HAS_NO_NOEXCEPT
#endif

#if __has_feature(underlying_type)
#  define _LIBCPP_UNDERLYING_TYPE(T) __underlying_type(T)
#endif

#if __has_feature(is_literal)
#  define _LIBCPP_IS_LITERAL(T) __is_literal(T)
#endif

// Inline namespaces are available in Clang regardless of C++ dialect.
#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD  } }
#define _VSTD std::_LIBCPP_NAMESPACE

namespace std {
  inline namespace _LIBCPP_NAMESPACE {
  }
}

#if !defined(_LIBCPP_HAS_NO_ASAN) && !__has_feature(address_sanitizer)
#define _LIBCPP_HAS_NO_ASAN
#endif

// Allow for build-time disabling of unsigned integer sanitization
#if !defined(_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK) && __has_attribute(no_sanitize)
#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute__((__no_sanitize__("unsigned-integer-overflow")))
#endif 

#elif defined(_LIBCPP_COMPILER_GCC)

#define _ALIGNAS(x) __attribute__((__aligned__(x)))
#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))

#define _LIBCPP_NORETURN __attribute__((noreturn))

#if _GNUC_VER >= 407
#define _LIBCPP_UNDERLYING_TYPE(T) __underlying_type(T)
#define _LIBCPP_IS_LITERAL(T) __is_literal_type(T)
#define _LIBCPP_HAS_IS_FINAL
#endif

#if defined(__GNUC__) && _GNUC_VER >= 403
#  define _LIBCPP_HAS_IS_BASE_OF
#endif

#if !__EXCEPTIONS
#define _LIBCPP_NO_EXCEPTIONS
#endif

// constexpr was added to GCC in 4.6.
#if _GNUC_VER < 406
#define _LIBCPP_HAS_NO_CONSTEXPR
// Can only use constexpr in c++11 mode.
#elif !defined(__GXX_EXPERIMENTAL_CXX0X__) && __cplusplus < 201103L
#define _LIBCPP_HAS_NO_CONSTEXPR
#endif

// Determine if GCC supports relaxed constexpr
#if !defined(__cpp_constexpr) || __cpp_constexpr < 201304L
#define _LIBCPP_HAS_NO_CXX14_CONSTEXPR
#endif

// GCC 5 will support variable templates
#if !defined(__cpp_variable_templates) || __cpp_variable_templates < 201304L
#define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES
#endif

#ifndef __GXX_EXPERIMENTAL_CXX0X__
#define _LIBCPP_HAS_NO_DECLTYPE
#define _LIBCPP_HAS_NO_NULLPTR
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_NO_VARIADICS
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#define _LIBCPP_HAS_NO_STRONG_ENUMS
#define _LIBCPP_HAS_NO_NOEXCEPT

#else  // __GXX_EXPERIMENTAL_CXX0X__

#if _GNUC_VER < 403
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#endif


#if _GNUC_VER < 404
#define _LIBCPP_HAS_NO_DECLTYPE
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_NO_VARIADICS
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#endif  // _GNUC_VER < 404

#if _GNUC_VER < 406
#define _LIBCPP_HAS_NO_NOEXCEPT
#define _LIBCPP_HAS_NO_NULLPTR
#endif

#endif  // __GXX_EXPERIMENTAL_CXX0X__

#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD  } }
#define _VSTD std::_LIBCPP_NAMESPACE

namespace std {
  inline namespace _LIBCPP_NAMESPACE {
  }
}

#if !defined(_LIBCPP_HAS_NO_ASAN) && !defined(__SANITIZE_ADDRESS__)
#define _LIBCPP_HAS_NO_ASAN
#endif

#elif defined(_LIBCPP_COMPILER_MSVC)

#define _LIBCPP_TOSTRING2(x) #x
#define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)
#define _LIBCPP_WARNING(x) __pragma(message(__FILE__ "(" _LIBCPP_TOSTRING(__LINE__) ") : warning note: " x))

#if _MSC_VER < 1900
#error "MSVC versions prior to Visual Studio 2015 are not supported"
#endif

#define _LIBCPP_HAS_IS_BASE_OF
#define _LIBCPP_HAS_NO_CONSTEXPR
#define _LIBCPP_HAS_NO_CXX14_CONSTEXPR
#define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES
#if _MSC_VER <= 1800
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#endif
#define _LIBCPP_HAS_NO_NOEXCEPT
#define __alignof__ __alignof
#define _LIBCPP_NORETURN __declspec(noreturn)
#define _ALIGNAS(x) __declspec(align(x))
#define _LIBCPP_HAS_NO_VARIADICS

#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {
#define _LIBCPP_END_NAMESPACE_STD  }
#define _VSTD std

#  define _LIBCPP_WEAK
namespace std {
}

#define _LIBCPP_HAS_NO_ASAN

#elif defined(_LIBCPP_COMPILER_IBM)

#define _ALIGNAS(x) __attribute__((__aligned__(x)))
#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
#define _ATTRIBUTE(x) __attribute__((x))
#define _LIBCPP_NORETURN __attribute__((noreturn))

#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#define _LIBCPP_HAS_NO_NOEXCEPT
#define _LIBCPP_HAS_NO_NULLPTR
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_IS_BASE_OF
#define _LIBCPP_HAS_IS_FINAL
#define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES

#if defined(_AIX)
#define __MULTILOCALE_API
#endif

#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD  } }
#define _VSTD std::_LIBCPP_NAMESPACE

namespace std {
  inline namespace _LIBCPP_NAMESPACE {
  }
}

#define _LIBCPP_HAS_NO_ASAN

#endif // _LIBCPP_COMPILER_[CLANG|GCC|MSVC|IBM]

#if defined(_LIBCPP_OBJECT_FORMAT_COFF)
#if defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
# define _LIBCPP_DLL_VIS
# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
# define _LIBCPP_OVERRIDABLE_FUNC_VIS
#elif defined(_LIBCPP_BUILDING_LIBRARY)
# define _LIBCPP_DLL_VIS __declspec(dllexport)
# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS _LIBCPP_DLL_VIS
# define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_DLL_VIS
#else
# define _LIBCPP_DLL_VIS __declspec(dllimport)
# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
# define _LIBCPP_OVERRIDABLE_FUNC_VIS
#endif

#define _LIBCPP_TYPE_VIS            _LIBCPP_DLL_VIS
#define _LIBCPP_FUNC_VIS            _LIBCPP_DLL_VIS
#define _LIBCPP_EXTERN_VIS          _LIBCPP_DLL_VIS
#define _LIBCPP_EXCEPTION_ABI       _LIBCPP_DLL_VIS
#define _LIBCPP_HIDDEN
#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
#define _LIBCPP_TEMPLATE_VIS
#define _LIBCPP_ENUM_VIS

#if defined(_LIBCPP_COMPILER_MSVC)
# define _LIBCPP_INLINE_VISIBILITY __forceinline
# define _LIBCPP_ALWAYS_INLINE     __forceinline
# define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __forceinline
#else
# define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__always_inline__))
# define _LIBCPP_ALWAYS_INLINE     __attribute__ ((__always_inline__))
# define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__ ((__always_inline__))
#endif
#endif // defined(_LIBCPP_OBJECT_FORMAT_COFF)

#ifndef _LIBCPP_HIDDEN
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_HIDDEN __attribute__ ((__visibility__("hidden")))
#else
#define _LIBCPP_HIDDEN
#endif
#endif

#ifndef _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
// The inline should be removed once PR32114 is resolved
#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS inline _LIBCPP_HIDDEN
#else
#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
#endif
#endif

#ifndef _LIBCPP_FUNC_VIS
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_FUNC_VIS __attribute__ ((__visibility__("default")))
#else
#define _LIBCPP_FUNC_VIS
#endif
#endif

#ifndef _LIBCPP_TYPE_VIS
#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#    define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
#  else
#    define _LIBCPP_TYPE_VIS
#  endif
#endif

#ifndef _LIBCPP_TEMPLATE_VIS
#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#    if __has_attribute(__type_visibility__)
#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__type_visibility__("default")))
#    else
#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__visibility__("default")))
#    endif
#  else
#    define _LIBCPP_TEMPLATE_VIS
#  endif
#endif

#ifndef _LIBCPP_EXTERN_VIS
# define _LIBCPP_EXTERN_VIS
#endif

#ifndef _LIBCPP_OVERRIDABLE_FUNC_VIS
# define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_FUNC_VIS
#endif

#ifndef _LIBCPP_EXCEPTION_ABI
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_EXCEPTION_ABI __attribute__ ((__visibility__("default")))
#else
#define _LIBCPP_EXCEPTION_ABI
#endif
#endif

#ifndef _LIBCPP_ENUM_VIS
#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
#    define _LIBCPP_ENUM_VIS __attribute__ ((__type_visibility__("default")))
#  else
#    define _LIBCPP_ENUM_VIS
#  endif
#endif

#ifndef _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__visibility__("default")))
#  else
#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
#  endif
#endif

#ifndef _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
#  define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
#endif

#ifndef _LIBCPP_INLINE_VISIBILITY
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__visibility__("hidden"), __always_inline__))
#else
#define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__always_inline__))
#endif
#endif

#ifndef _LIBCPP_ALWAYS_INLINE
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_ALWAYS_INLINE  __attribute__ ((__visibility__("hidden"), __always_inline__))
#else
#define _LIBCPP_ALWAYS_INLINE  __attribute__ ((__always_inline__))
#endif
#endif

#ifndef _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
# if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#  define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__((__visibility__("default"), __always_inline__))
# else
#  define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__((__always_inline__))
# endif
#endif

#ifndef _LIBCPP_PREFERRED_OVERLOAD
#  if __has_attribute(__enable_if__)
#    define _LIBCPP_PREFERRED_OVERLOAD __attribute__ ((__enable_if__(true, "")))
#  endif
#endif

#ifndef _LIBCPP_HAS_NO_NOEXCEPT
#  define _NOEXCEPT noexcept
#  define _NOEXCEPT_(x) noexcept(x)
#else
#  define _NOEXCEPT throw()
#  define _NOEXCEPT_(x)
#endif

#if defined(_LIBCPP_DEBUG_USE_EXCEPTIONS)
# if !defined(_LIBCPP_DEBUG)
#   error cannot use _LIBCPP_DEBUG_USE_EXCEPTIONS unless _LIBCPP_DEBUG is defined
# endif
# define _NOEXCEPT_DEBUG noexcept(false)
# define _NOEXCEPT_DEBUG_(x) noexcept(false)
#else
# define _NOEXCEPT_DEBUG _NOEXCEPT
# define _NOEXCEPT_DEBUG_(x) _NOEXCEPT_(x)
#endif

#ifdef _LIBCPP_HAS_NO_UNICODE_CHARS
typedef unsigned short char16_t;
typedef unsigned int   char32_t;
#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS

#ifndef __SIZEOF_INT128__
#define _LIBCPP_HAS_NO_INT128
#endif

#ifdef _LIBCPP_CXX03_LANG
# if __has_extension(c_static_assert)
#   define static_assert(__b, __m) _Static_assert(__b, __m)
# else
extern "C++" {
template <bool> struct __static_assert_test;
template <> struct __static_assert_test<true> {};
template <unsigned> struct __static_assert_check {};
}
#define static_assert(__b, __m) \
    typedef __static_assert_check<sizeof(__static_assert_test<(__b)>)> \
    _LIBCPP_CONCAT(__t, __LINE__)
# endif // __has_extension(c_static_assert)
#endif  // _LIBCPP_CXX03_LANG

#ifdef _LIBCPP_HAS_NO_DECLTYPE
// GCC 4.6 provides __decltype in all standard modes.
#if __has_keyword(__decltype) || _LIBCPP_CLANG_VER >= 304 || _GNUC_VER >= 406
#  define decltype(__x) __decltype(__x)
#else
#  define decltype(__x) __typeof__(__x)
#endif
#endif

#ifdef _LIBCPP_HAS_NO_CONSTEXPR
#define _LIBCPP_CONSTEXPR
#else
#define _LIBCPP_CONSTEXPR constexpr
#endif

#ifdef _LIBCPP_CXX03_LANG
#define _LIBCPP_DEFAULT {}
#else
#define _LIBCPP_DEFAULT = default;
#endif

#ifdef _LIBCPP_CXX03_LANG
#define _LIBCPP_EQUAL_DELETE
#else
#define _LIBCPP_EQUAL_DELETE = delete
#endif

#ifdef __GNUC__
#define _NOALIAS __attribute__((__malloc__))
#else
#define _NOALIAS
#endif

#if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__) || \
    (!defined(_LIBCPP_CXX03_LANG) && defined(__GNUC__)) // All supported GCC versions
#   define _LIBCPP_EXPLICIT explicit
#else
#   define _LIBCPP_EXPLICIT
#endif

#if !__has_builtin(__builtin_operator_new) || !__has_builtin(__builtin_operator_delete)
#   define _LIBCPP_HAS_NO_BUILTIN_OPERATOR_NEW_DELETE
#endif

#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
#define _LIBCPP_DECLARE_STRONG_ENUM(x) struct _LIBCPP_TYPE_VIS x { enum __lx
#define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x) \
    __lx __v_; \
    _LIBCPP_ALWAYS_INLINE x(__lx __v) : __v_(__v) {} \
    _LIBCPP_ALWAYS_INLINE explicit x(int __v) : __v_(static_cast<__lx>(__v)) {} \
    _LIBCPP_ALWAYS_INLINE operator int() const {return __v_;} \
    };
#else  // _LIBCPP_HAS_NO_STRONG_ENUMS
#define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class _LIBCPP_ENUM_VIS x
#define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
#endif  // _LIBCPP_HAS_NO_STRONG_ENUMS

#ifdef _LIBCPP_DEBUG
#   if _LIBCPP_DEBUG == 0
#       define _LIBCPP_DEBUG_LEVEL 1
#   elif _LIBCPP_DEBUG == 1
#       define _LIBCPP_DEBUG_LEVEL 2
#   else
#       error Supported values for _LIBCPP_DEBUG are 0 and 1
#   endif
# if !defined(_LIBCPP_BUILDING_LIBRARY)
#   define _LIBCPP_EXTERN_TEMPLATE(...)
# endif
#endif

#ifdef _LIBCPP_DISABLE_EXTERN_TEMPLATE
#define _LIBCPP_EXTERN_TEMPLATE(...)
#define _LIBCPP_EXTERN_TEMPLATE2(...)
#endif

#ifndef _LIBCPP_EXTERN_TEMPLATE
#define _LIBCPP_EXTERN_TEMPLATE(...) extern template __VA_ARGS__;
#endif

#ifndef _LIBCPP_EXTERN_TEMPLATE2
#define _LIBCPP_EXTERN_TEMPLATE2(...) extern template __VA_ARGS__;
#endif

#if defined(__APPLE__) && defined(__LP64__) && !defined(__x86_64__)
#define _LIBCPP_NONUNIQUE_RTTI_BIT (1ULL << 63)
#endif

#if defined(__APPLE__) || defined(__FreeBSD__) || defined(_LIBCPP_MSVCRT) ||   \
    defined(__sun__) || defined(__NetBSD__) || defined(__CloudABI__)
#define _LIBCPP_LOCALE__L_EXTENSIONS 1
#endif

#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
// Most unix variants have catopen.  These are the specific ones that don't.
#if !defined(__BIONIC__) && !defined(_NEWLIB_VERSION)
#define _LIBCPP_HAS_CATOPEN 1
#endif
#endif

#ifdef __FreeBSD__
#define _DECLARE_C99_LDBL_MATH 1
#endif

#if defined(__APPLE__)
# if !defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && \
     defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
#   define __MAC_OS_X_VERSION_MIN_REQUIRED __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__
# endif
# if defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
#   if __MAC_OS_X_VERSION_MIN_REQUIRED < 1060
#     define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
#   endif
# endif
#endif // defined(__APPLE__)

#if defined(__APPLE__) || defined(__FreeBSD__)
#define _LIBCPP_HAS_DEFAULTRUNELOCALE
#endif

#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__sun__)
#define _LIBCPP_WCTYPE_IS_MASK
#endif

#ifndef _LIBCPP_STD_VER
#  if  __cplusplus <= 201103L
#    define _LIBCPP_STD_VER 11
#  elif __cplusplus <= 201402L
#    define _LIBCPP_STD_VER 14
#  elif __cplusplus <= 201703L
#    define _LIBCPP_STD_VER 17
#  else
#    define _LIBCPP_STD_VER 18  // current year, or date of c++2a ratification
#  endif
#endif  // _LIBCPP_STD_VER

#if _LIBCPP_STD_VER > 11
#define _LIBCPP_DEPRECATED [[deprecated]]
#else
#define _LIBCPP_DEPRECATED
#endif

#if _LIBCPP_STD_VER <= 11
#define _LIBCPP_EXPLICIT_AFTER_CXX11
#define _LIBCPP_DEPRECATED_AFTER_CXX11
#else
#define _LIBCPP_EXPLICIT_AFTER_CXX11 explicit
#define _LIBCPP_DEPRECATED_AFTER_CXX11 [[deprecated]]
#endif

#if _LIBCPP_STD_VER > 11 && !defined(_LIBCPP_HAS_NO_CXX14_CONSTEXPR)
#define _LIBCPP_CONSTEXPR_AFTER_CXX11 constexpr
#else
#define _LIBCPP_CONSTEXPR_AFTER_CXX11
#endif

#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_CXX14_CONSTEXPR)
#define _LIBCPP_CONSTEXPR_AFTER_CXX14 constexpr
#else
#define _LIBCPP_CONSTEXPR_AFTER_CXX14
#endif

// FIXME: Remove all usages of this macro once compilers catch up.
#if !defined(__cpp_inline_variables) || (__cpp_inline_variables < 201606L)
# define _LIBCPP_HAS_NO_INLINE_VARIABLES
#endif

#ifdef _LIBCPP_HAS_NO_RVALUE_REFERENCES
#  define _LIBCPP_EXPLICIT_MOVE(x) _VSTD::move(x)
#else
#  define _LIBCPP_EXPLICIT_MOVE(x) (x)
#endif

#ifndef _LIBCPP_HAS_NO_ASAN
_LIBCPP_FUNC_VIS extern "C" void __sanitizer_annotate_contiguous_container(
  const void *, const void *, const void *, const void *);
#endif

// Try to find out if RTTI is disabled.
// g++ and cl.exe have RTTI on by default and define a macro when it is.
// g++ only defines the macro in 4.3.2 and onwards.
#if !defined(_LIBCPP_NO_RTTI)
#  if defined(__GNUC__) && ((__GNUC__ >= 5) || (__GNUC__ == 4 && \
   (__GNUC_MINOR__ >= 3 || __GNUC_PATCHLEVEL__ >= 2))) && !defined(__GXX_RTTI)
#    define _LIBCPP_NO_RTTI
#  elif defined(_LIBCPP_COMPILER_MSVC) && !defined(_CPPRTTI)
#    define _LIBCPP_NO_RTTI
#  endif
#endif

#ifndef _LIBCPP_WEAK
#  define _LIBCPP_WEAK __attribute__((__weak__))
#endif

// Thread API
#if !defined(_LIBCPP_HAS_NO_THREADS) && \
    !defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && \
    !defined(_LIBCPP_HAS_THREAD_API_WIN32) && \
    !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
# if defined(__FreeBSD__) || \
    defined(__Fuchsia__) || \
    defined(__NetBSD__) || \
    defined(__linux__) || \
    defined(__APPLE__) || \
    defined(__CloudABI__) || \
    defined(__sun__) || \
    (defined(__MINGW32__) && __libcpp_has_include(<pthread.h>))
#   define _LIBCPP_HAS_THREAD_API_PTHREAD
# elif defined(_LIBCPP_WIN32API)
#  define _LIBCPP_HAS_THREAD_API_WIN32
# else
#  error "No thread API"
# endif // _LIBCPP_HAS_THREAD_API
#endif // _LIBCPP_HAS_NO_THREADS

#if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
#  error _LIBCPP_HAS_THREAD_API_PTHREAD may only be defined when \
         _LIBCPP_HAS_NO_THREADS is not defined.
#endif

#if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
#  error _LIBCPP_HAS_THREAD_API_EXTERNAL may not be defined when \
         _LIBCPP_HAS_NO_THREADS is defined.
#endif

#if defined(_LIBCPP_HAS_NO_MONOTONIC_CLOCK) && !defined(_LIBCPP_HAS_NO_THREADS)
#  error _LIBCPP_HAS_NO_MONOTONIC_CLOCK may only be defined when \
         _LIBCPP_HAS_NO_THREADS is defined.
#endif

// Systems that use capability-based security (FreeBSD with Capsicum,
// Nuxi CloudABI) may only provide local filesystem access (using *at()).
// Functions like open(), rename(), unlink() and stat() should not be
// used, as they attempt to access the global filesystem namespace.
#ifdef __CloudABI__
#define _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE
#endif

// CloudABI is intended for running networked services. Processes do not
// have standard input and output channels.
#ifdef __CloudABI__
#define _LIBCPP_HAS_NO_STDIN
#define _LIBCPP_HAS_NO_STDOUT
#endif

#if defined(__BIONIC__) || defined(__CloudABI__) ||                            \
    defined(__Fuchsia__) || defined(_LIBCPP_HAS_MUSL_LIBC)
#define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
#endif

// Thread-unsafe functions such as strtok() and localtime()
// are not available.
#ifdef __CloudABI__
#define _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
#endif

#if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
#define _LIBCPP_HAS_C_ATOMIC_IMP
#elif _GNUC_VER > 407
#define _LIBCPP_HAS_GCC_ATOMIC_IMP
#endif

#if (!defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)) \
     || defined(_LIBCPP_HAS_NO_THREADS)
#define _LIBCPP_HAS_NO_ATOMIC_HEADER
#endif

#ifndef _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
#endif

#if defined(_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS)
#if defined(__clang__) && __has_attribute(acquire_capability)
// Work around the attribute handling in clang.  When both __declspec and
// __attribute__ are present, the processing goes awry preventing the definition
// of the types.
#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
#define _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
#endif
#endif
#endif

#if __has_attribute(require_constant_initialization)
#define _LIBCPP_SAFE_STATIC __attribute__((__require_constant_initialization__))
#else
#define _LIBCPP_SAFE_STATIC
#endif

#if !__has_builtin(__builtin_addressof) && _GNUC_VER < 700
# define _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
#endif

#if !defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
#if defined(_LIBCPP_MSVCRT) || defined(_NEWLIB_VERSION)
#define _LIBCPP_HAS_NO_OFF_T_FUNCTIONS
#endif
#endif

#if __has_attribute(diagnose_if) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
# define _LIBCPP_DIAGNOSE_WARNING(...) \
    __attribute__((diagnose_if(__VA_ARGS__, "warning")))
# define _LIBCPP_DIAGNOSE_ERROR(...) \
    __attribute__((diagnose_if(__VA_ARGS__, "error")))
#else
# define _LIBCPP_DIAGNOSE_WARNING(...)
# define _LIBCPP_DIAGNOSE_ERROR(...)
#endif

#if __has_attribute(fallthough) || _GNUC_VER >= 700
// Use a function like macro to imply that it must be followed by a semicolon
#define _LIBCPP_FALLTHROUGH() __attribute__((__fallthrough__))
#else
#define _LIBCPP_FALLTHROUGH() ((void)0)
#endif

#if defined(_LIBCPP_ABI_MICROSOFT) && \
   (defined(_LIBCPP_COMPILER_MSVC) || __has_declspec_attribute(empty_bases))
# define _LIBCPP_DECLSPEC_EMPTY_BASES __declspec(empty_bases)
#else
# define _LIBCPP_DECLSPEC_EMPTY_BASES
#endif

#if defined(_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES)
# define _LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR
# define _LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS
# define _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
# define _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
#endif // _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES

#if !defined(__cpp_deduction_guides) || __cpp_deduction_guides < 201611
# define _LIBCPP_HAS_NO_DEDUCTION_GUIDES
#endif

#if !__has_keyword(__is_aggregate) && (_GNUC_VER_NEW < 7001)
# define _LIBCPP_HAS_NO_IS_AGGREGATE
#endif

#if !defined(__cpp_coroutines) || __cpp_coroutines < 201703L
# define _LIBCPP_HAS_NO_COROUTINES
#endif

// Decide whether to use availability macros.
#if !defined(_LIBCPP_BUILDING_LIBRARY) &&                                      \
    !defined(_LIBCPP_DISABLE_AVAILABILITY) &&                                  \
    __has_feature(attribute_availability_with_strict) &&                       \
    __has_feature(attribute_availability_in_templates)
#ifdef __APPLE__
#define _LIBCPP_USE_AVAILABILITY_APPLE
#endif
#endif

// Define availability macros.
#if defined(_LIBCPP_USE_AVAILABILITY_APPLE)
#define _LIBCPP_AVAILABILITY_SHARED_MUTEX                                      \
  __attribute__((availability(macosx,strict,introduced=10.12)))                \
  __attribute__((availability(ios,strict,introduced=10.0)))                    \
  __attribute__((availability(tvos,strict,introduced=10.0)))                   \
  __attribute__((availability(watchos,strict,introduced=3.0)))
#define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS __attribute__((unavailable))
#define _LIBCPP_AVAILABILITY_BAD_ARRAY_LENGTH __attribute__((unavailable))
#define _LIBCPP_AVAILABILITY_BAD_ANY_CAST __attribute__((unavailable))
#define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS                               \
  __attribute__((availability(macosx,strict,introduced=10.12)))                \
  __attribute__((availability(ios,strict,introduced=10.0)))                    \
  __attribute__((availability(tvos,strict,introduced=10.0)))                   \
  __attribute__((availability(watchos,strict,introduced=3.0)))
#define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE                                  \
  __attribute__((availability(macosx,strict,introduced=10.12)))                \
  __attribute__((availability(ios,strict,introduced=10.0)))                    \
  __attribute__((availability(tvos,strict,introduced=10.0)))                   \
  __attribute__((availability(watchos,strict,introduced=3.0)))
#define _LIBCPP_AVAILABILITY_FUTURE_ERROR                                      \
  __attribute__((availability(ios,strict,introduced=6.0)))
#define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE                                   \
  __attribute__((availability(macosx,strict,introduced=10.9)))                 \
  __attribute__((availability(ios,strict,introduced=7.0)))
#define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY                                   \
  __attribute__((availability(macosx,strict,introduced=10.9)))                 \
  __attribute__((availability(ios,strict,introduced=7.0)))
#define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR                                 \
  __attribute__((availability(macosx,strict,introduced=10.9)))                 \
  __attribute__((availability(ios,strict,introduced=7.0)))
#else
#define _LIBCPP_AVAILABILITY_SHARED_MUTEX
#define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
#define _LIBCPP_AVAILABILITY_BAD_ARRAY_LENGTH
#define _LIBCPP_AVAILABILITY_BAD_ANY_CAST
#define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS
#define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE
#define _LIBCPP_AVAILABILITY_FUTURE_ERROR
#define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
#define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY
#define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
#endif

// Define availability that depends on _LIBCPP_NO_EXCEPTIONS.
#ifdef _LIBCPP_NO_EXCEPTIONS
#define _LIBCPP_AVAILABILITY_DYNARRAY
#define _LIBCPP_AVAILABILITY_FUTURE
#define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
#else
#define _LIBCPP_AVAILABILITY_DYNARRAY _LIBCPP_AVAILABILITY_BAD_ARRAY_LENGTH
#define _LIBCPP_AVAILABILITY_FUTURE _LIBCPP_AVAILABILITY_FUTURE_ERROR
#define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST                                \
  _LIBCPP_AVAILABILITY_BAD_ANY_CAST
#endif

// Availability of stream API in the dylib got dropped and re-added.  The
// extern template should effectively be available at:
//    availability(macosx,introduced=10.9)
//    availability(ios,introduced=7.0)
#if defined(_LIBCPP_USE_AVAILABILITY_APPLE) &&                                 \
    ((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) &&                \
      __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1090) ||                 \
     (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) &&               \
      __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 70000))
#define _LIBCPP_AVAILABILITY_NO_STREAMS_EXTERN_TEMPLATE
#endif

#if defined(_LIBCPP_COMPILER_IBM)
#define _LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO
#endif

#if defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
# define _LIBCPP_PUSH_MACROS
# define _LIBCPP_POP_MACROS
#else
  // Don't warn about macro conflicts when we can restore them at the
  // end of the header.
# ifndef _LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS
#   define _LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS
# endif
# if defined(_LIBCPP_COMPILER_MSVC)
#   define _LIBCPP_PUSH_MACROS    \
      __pragma(push_macro("min")) \
      __pragma(push_macro("max"))
#   define _LIBCPP_POP_MACROS     \
      __pragma(pop_macro("min"))  \
      __pragma(pop_macro("max"))
# else
#   define _LIBCPP_PUSH_MACROS        \
      _Pragma("push_macro(\"min\")")  \
      _Pragma("push_macro(\"max\")")
#   define _LIBCPP_POP_MACROS         \
      _Pragma("pop_macro(\"min\")")   \
      _Pragma("pop_macro(\"max\")")
# endif
#endif // defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)


#endif // __cplusplus

#endif // _LIBCPP_CONFIG

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL namespace std { namespace experimental {
#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL  } }
#define _VSTD_EXPERIMENTAL std::experimental

#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
#define _LIBCPP_END_NAMESPACE_LFTS  } } }
#define _VSTD_LFTS _VSTD_EXPERIMENTAL::fundamentals_v1

#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
#define _LIBCPP_END_NAMESPACE_LFTS_V2  } } }
#define _VSTD_LFTS_V2 _VSTD_EXPERIMENTAL::fundamentals_v2

#define _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR _LIBCPP_BEGIN_NAMESPACE_LFTS namespace pmr {
#define _LIBCPP_END_NAMESPACE_LFTS_PMR _LIBCPP_END_NAMESPACE_LFTS }
#define _VSTD_LFTS_PMR _VSTD_LFTS::pmr

#define _LIBCPP_BEGIN_NAMESPACE_CHRONO_LFTS _LIBCPP_BEGIN_NAMESPACE_STD        \
  namespace chrono { namespace experimental { inline namespace fundamentals_v1 {
#define _LIBCPP_END_NAMESPACE_CHRONO_LFTS _LIBCPP_END_NAMESPACE_STD } } }

#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
    _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL namespace filesystem { \
    inline namespace v1 {

#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
    } } _LIBCPP_END_NAMESPACE_EXPERIMENTAL

#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES \
  _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace coroutines_v1 {

#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES \
  } _LIBCPP_END_NAMESPACE_EXPERIMENTAL

#define _VSTD_CORO _VSTD_EXPERIMENTAL::coroutines_v1

#define _VSTD_FS ::std::experimental::filesystem::v1

#endif
#include <new>
#include <type_traits>
#include <functional>
#include <memory> // for hash<T*>
#include <cstddef>
#include <cassert>
// -*- C++ -*-
//===--------------------------- __debug ----------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_DEBUG_H
#define _LIBCPP_DEBUG_H

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

#if defined(_LIBCPP_HAS_NO_NULLPTR)
# include <cstddef>
#endif

#if _LIBCPP_DEBUG_LEVEL >= 1 || defined(_LIBCPP_BUILDING_LIBRARY)
#   include <cstdlib>
#   include <cstdio>
#   include <cstddef>
#   include <exception>
#endif

#if _LIBCPP_DEBUG_LEVEL >= 1 && !defined(_LIBCPP_ASSERT)
# define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : \
  _VSTD::__libcpp_debug_function(_VSTD::__libcpp_debug_info(__FILE__, __LINE__, #x, m)))
#endif

#if _LIBCPP_DEBUG_LEVEL >= 2
#ifndef _LIBCPP_DEBUG_ASSERT
#define _LIBCPP_DEBUG_ASSERT(x, m) _LIBCPP_ASSERT(x, m)
#endif
#define _LIBCPP_DEBUG_MODE(...) __VA_ARGS__
#endif

#ifndef _LIBCPP_ASSERT
#   define _LIBCPP_ASSERT(x, m) ((void)0)
#endif
#ifndef _LIBCPP_DEBUG_ASSERT
#   define _LIBCPP_DEBUG_ASSERT(x, m) ((void)0)
#endif
#ifndef _LIBCPP_DEBUG_MODE
#define _LIBCPP_DEBUG_MODE(...) ((void)0)
#endif

#if _LIBCPP_DEBUG_LEVEL < 1
class _LIBCPP_EXCEPTION_ABI __libcpp_debug_exception;
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

struct _LIBCPP_TEMPLATE_VIS __libcpp_debug_info {
  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
  __libcpp_debug_info()
      : __file_(nullptr), __line_(-1), __pred_(nullptr), __msg_(nullptr) {}
  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
  __libcpp_debug_info(const char* __f, int __l, const char* __p, const char* __m)
    : __file_(__f), __line_(__l), __pred_(__p), __msg_(__m) {}
  const char* __file_;
  int __line_;
  const char* __pred_;
  const char* __msg_;
};

/// __libcpp_debug_function_type - The type of the assertion failure handler.
typedef void(*__libcpp_debug_function_type)(__libcpp_debug_info const&);

/// __libcpp_debug_function - The handler function called when a _LIBCPP_ASSERT
///    fails.
extern _LIBCPP_EXTERN_VIS __libcpp_debug_function_type __libcpp_debug_function;

/// __libcpp_abort_debug_function - A debug handler that aborts when called.
_LIBCPP_NORETURN _LIBCPP_FUNC_VIS
void __libcpp_abort_debug_function(__libcpp_debug_info const&);

/// __libcpp_throw_debug_function - A debug handler that throws
///   an instance of __libcpp_debug_exception when called.
 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS
void __libcpp_throw_debug_function(__libcpp_debug_info const&);

/// __libcpp_set_debug_function - Set the debug handler to the specified
///    function.
_LIBCPP_FUNC_VIS
bool __libcpp_set_debug_function(__libcpp_debug_function_type __func);

// Setup the throwing debug handler during dynamic initialization.
#if _LIBCPP_DEBUG_LEVEL >= 1 && defined(_LIBCPP_DEBUG_USE_EXCEPTIONS)
# if defined(_LIBCPP_NO_EXCEPTIONS)
#   error _LIBCPP_DEBUG_USE_EXCEPTIONS cannot be used when exceptions are disabled.
# endif
static bool __init_dummy = __libcpp_set_debug_function(__libcpp_throw_debug_function);
#endif

#if _LIBCPP_DEBUG_LEVEL >= 1 || defined(_LIBCPP_BUILDING_LIBRARY)
class _LIBCPP_EXCEPTION_ABI __libcpp_debug_exception : public exception {
public:
  __libcpp_debug_exception() _NOEXCEPT;
  explicit __libcpp_debug_exception(__libcpp_debug_info const& __i);
  __libcpp_debug_exception(__libcpp_debug_exception const&);
  ~__libcpp_debug_exception() _NOEXCEPT;
  const char* what() const _NOEXCEPT;
private:
  struct __libcpp_debug_exception_imp;
  __libcpp_debug_exception_imp *__imp_;
};
#endif

#if _LIBCPP_DEBUG_LEVEL >= 2 || defined(_LIBCPP_BUILDING_LIBRARY)

struct _LIBCPP_TYPE_VIS __c_node;

struct _LIBCPP_TYPE_VIS __i_node
{
    void* __i_;
    __i_node* __next_;
    __c_node* __c_;

#ifndef _LIBCPP_CXX03_LANG
    __i_node(const __i_node&) = delete;
    __i_node& operator=(const __i_node&) = delete;
#else
private:
    __i_node(const __i_node&);
    __i_node& operator=(const __i_node&);
public:
#endif
    _LIBCPP_INLINE_VISIBILITY
    __i_node(void* __i, __i_node* __next, __c_node* __c)
        : __i_(__i), __next_(__next), __c_(__c) {}
    ~__i_node();
};

struct _LIBCPP_TYPE_VIS __c_node
{
    void* __c_;
    __c_node* __next_;
    __i_node** beg_;
    __i_node** end_;
    __i_node** cap_;

#ifndef _LIBCPP_CXX03_LANG
    __c_node(const __c_node&) = delete;
    __c_node& operator=(const __c_node&) = delete;
#else
private:
    __c_node(const __c_node&);
    __c_node& operator=(const __c_node&);
public:
#endif
    _LIBCPP_INLINE_VISIBILITY
    __c_node(void* __c, __c_node* __next)
        : __c_(__c), __next_(__next), beg_(nullptr), end_(nullptr), cap_(nullptr) {}
    virtual ~__c_node();

    virtual bool __dereferenceable(const void*) const = 0;
    virtual bool __decrementable(const void*) const = 0;
    virtual bool __addable(const void*, ptrdiff_t) const = 0;
    virtual bool __subscriptable(const void*, ptrdiff_t) const = 0;

    void __add(__i_node* __i);
    _LIBCPP_HIDDEN void __remove(__i_node* __i);
};

template <class _Cont>
struct _C_node
    : public __c_node
{
    _C_node(void* __c, __c_node* __n)
        : __c_node(__c, __n) {}

    virtual bool __dereferenceable(const void*) const;
    virtual bool __decrementable(const void*) const;
    virtual bool __addable(const void*, ptrdiff_t) const;
    virtual bool __subscriptable(const void*, ptrdiff_t) const;
};

template <class _Cont>
inline bool
_C_node<_Cont>::__dereferenceable(const void* __i) const
{
    typedef typename _Cont::const_iterator iterator;
    const iterator* __j = static_cast<const iterator*>(__i);
    _Cont* _Cp = static_cast<_Cont*>(__c_);
    return _Cp->__dereferenceable(__j);
}

template <class _Cont>
inline bool
_C_node<_Cont>::__decrementable(const void* __i) const
{
    typedef typename _Cont::const_iterator iterator;
    const iterator* __j = static_cast<const iterator*>(__i);
    _Cont* _Cp = static_cast<_Cont*>(__c_);
    return _Cp->__decrementable(__j);
}

template <class _Cont>
inline bool
_C_node<_Cont>::__addable(const void* __i, ptrdiff_t __n) const
{
    typedef typename _Cont::const_iterator iterator;
    const iterator* __j = static_cast<const iterator*>(__i);
    _Cont* _Cp = static_cast<_Cont*>(__c_);
    return _Cp->__addable(__j, __n);
}

template <class _Cont>
inline bool
_C_node<_Cont>::__subscriptable(const void* __i, ptrdiff_t __n) const
{
    typedef typename _Cont::const_iterator iterator;
    const iterator* __j = static_cast<const iterator*>(__i);
    _Cont* _Cp = static_cast<_Cont*>(__c_);
    return _Cp->__subscriptable(__j, __n);
}

class _LIBCPP_TYPE_VIS __libcpp_db
{
    __c_node** __cbeg_;
    __c_node** __cend_;
    size_t   __csz_;
    __i_node** __ibeg_;
    __i_node** __iend_;
    size_t   __isz_;

    __libcpp_db();
public:
#ifndef _LIBCPP_CXX03_LANG
    __libcpp_db(const __libcpp_db&) = delete;
    __libcpp_db& operator=(const __libcpp_db&) = delete;
#else
private:
    __libcpp_db(const __libcpp_db&);
    __libcpp_db& operator=(const __libcpp_db&);
public:
#endif
    ~__libcpp_db();

    class __db_c_iterator;
    class __db_c_const_iterator;
    class __db_i_iterator;
    class __db_i_const_iterator;

    __db_c_const_iterator __c_end() const;
    __db_i_const_iterator __i_end() const;

    template <class _Cont>
    _LIBCPP_INLINE_VISIBILITY
    void __insert_c(_Cont* __c)
    {
        __c_node* __n = __insert_c(static_cast<void*>(__c));
        ::new(__n) _C_node<_Cont>(__n->__c_, __n->__next_);
    }

    void __insert_i(void* __i);
    __c_node* __insert_c(void* __c);
    void __erase_c(void* __c);

    void __insert_ic(void* __i, const void* __c);
    void __iterator_copy(void* __i, const void* __i0);
    void __erase_i(void* __i);

    void* __find_c_from_i(void* __i) const;
    void __invalidate_all(void* __c);
    __c_node* __find_c_and_lock(void* __c) const;
    __c_node* __find_c(void* __c) const;
    void unlock() const;

    void swap(void* __c1, void* __c2);


    bool __dereferenceable(const void* __i) const;
    bool __decrementable(const void* __i) const;
    bool __addable(const void* __i, ptrdiff_t __n) const;
    bool __subscriptable(const void* __i, ptrdiff_t __n) const;
    bool __less_than_comparable(const void* __i, const void* __j) const;
private:
    _LIBCPP_HIDDEN
    __i_node* __insert_iterator(void* __i);
    _LIBCPP_HIDDEN
    __i_node* __find_iterator(const void* __i) const;

    friend _LIBCPP_FUNC_VIS __libcpp_db* __get_db();
};

_LIBCPP_FUNC_VIS __libcpp_db* __get_db();
_LIBCPP_FUNC_VIS const __libcpp_db* __get_const_db();


#endif // _LIBCPP_DEBUG_LEVEL >= 2 || defined(_LIBCPP_BUILDING_LIBRARY)

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_DEBUG_H


#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

#ifdef _LIBCPP_HAS_NO_COROUTINES
# if defined(_LIBCPP_WARNING)
    _LIBCPP_WARNING("<experimental/coroutine> cannot be used with this compiler")
# else
#   warning <experimental/coroutine> cannot be used with this compiler
# endif
#endif

#ifndef _LIBCPP_HAS_NO_COROUTINES

_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES

template <class _Tp, class = void>
struct __coroutine_traits_sfinae {};

template <class _Tp>
struct __coroutine_traits_sfinae<
    _Tp, typename __void_t<typename _Tp::promise_type>::type>
{
  using promise_type = typename _Tp::promise_type;
};

template <typename _Ret, typename... _Args>
struct _LIBCPP_TEMPLATE_VIS coroutine_traits
    : public __coroutine_traits_sfinae<_Ret>
{
};

template <typename _Promise = void>
class _LIBCPP_TEMPLATE_VIS coroutine_handle;

template <>
class _LIBCPP_TEMPLATE_VIS coroutine_handle<void> {
public:
    _LIBCPP_ALWAYS_INLINE
    _LIBCPP_CONSTEXPR coroutine_handle() _NOEXCEPT : __handle_(nullptr) {}

    _LIBCPP_ALWAYS_INLINE
    _LIBCPP_CONSTEXPR coroutine_handle(nullptr_t) _NOEXCEPT : __handle_(nullptr) {}

    _LIBCPP_ALWAYS_INLINE
    coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
        __handle_ = nullptr;
        return *this;
    }

    _LIBCPP_ALWAYS_INLINE
    _LIBCPP_CONSTEXPR void* address() const _NOEXCEPT { return __handle_; }

    _LIBCPP_ALWAYS_INLINE
    _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return __handle_; }

    _LIBCPP_ALWAYS_INLINE
    void operator()() { resume(); }

    _LIBCPP_ALWAYS_INLINE
    void resume() {
      _LIBCPP_ASSERT(__is_suspended(),
                     "resume() can only be called on suspended coroutines");
      _LIBCPP_ASSERT(!done(),
                "resume() has undefined behavior when the coroutine is done");
      __builtin_coro_resume(__handle_);
    }

    _LIBCPP_ALWAYS_INLINE
    void destroy() {
      _LIBCPP_ASSERT(__is_suspended(),
                     "destroy() can only be called on suspended coroutines");
      __builtin_coro_destroy(__handle_);
    }

    _LIBCPP_ALWAYS_INLINE
    bool done() const {
      _LIBCPP_ASSERT(__is_suspended(),
                     "done() can only be called on suspended coroutines");
      return __builtin_coro_done(__handle_);
    }

public:
    _LIBCPP_ALWAYS_INLINE
    static coroutine_handle from_address(void* __addr) _NOEXCEPT {
        coroutine_handle __tmp;
        __tmp.__handle_ = __addr;
        return __tmp;
    }

    // FIXME: Should from_address(nullptr) be allowed?
    _LIBCPP_ALWAYS_INLINE
    static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
      return coroutine_handle(nullptr);
    }

    template <class _Tp, bool _CallIsValid = false>
    static coroutine_handle from_address(_Tp*) {
      static_assert(_CallIsValid,
       "coroutine_handle<void>::from_address cannot be called with "
        "non-void pointers");
    }

private:
  bool __is_suspended() const _NOEXCEPT  {
    // FIXME actually implement a check for if the coro is suspended.
    return __handle_;
  }

  template <class _PromiseT> friend class coroutine_handle;
  void* __handle_;
};

// 18.11.2.7 comparison operators:
inline _LIBCPP_ALWAYS_INLINE
bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return __x.address() == __y.address();
}
inline _LIBCPP_ALWAYS_INLINE
bool operator!=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return !(__x == __y);
}
inline _LIBCPP_ALWAYS_INLINE
bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return less<void*>()(__x.address(), __y.address());
}
inline _LIBCPP_ALWAYS_INLINE
bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return __y < __x;
}
inline _LIBCPP_ALWAYS_INLINE
bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return !(__x > __y);
}
inline _LIBCPP_ALWAYS_INLINE
bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
    return !(__x < __y);
}

template <typename _Promise>
class _LIBCPP_TEMPLATE_VIS coroutine_handle : public coroutine_handle<> {
    using _Base = coroutine_handle<>;
public:
#ifndef _LIBCPP_CXX03_LANG
    // 18.11.2.1 construct/reset
    using coroutine_handle<>::coroutine_handle;
#else
    _LIBCPP_ALWAYS_INLINE coroutine_handle() _NOEXCEPT : _Base() {}
    _LIBCPP_ALWAYS_INLINE coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {}
#endif
    _LIBCPP_INLINE_VISIBILITY
    coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
        _Base::operator=(nullptr);
        return *this;
    }

    _LIBCPP_INLINE_VISIBILITY
    _Promise& promise() const {
        return *reinterpret_cast<_Promise*>(
            __builtin_coro_promise(this->__handle_, __alignof(_Promise), false));
    }

public:
    _LIBCPP_ALWAYS_INLINE
    static coroutine_handle from_address(void* __addr) _NOEXCEPT {
        coroutine_handle __tmp;
        __tmp.__handle_ = __addr;
        return __tmp;
    }

    // NOTE: this overload isn't required by the standard but is needed so
    // the deleted _Promise* overload doesn't make from_address(nullptr)
    // ambiguous.
    // FIXME: should from_address work with nullptr?
    _LIBCPP_ALWAYS_INLINE
    static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
      return coroutine_handle(nullptr);
    }

    template <class _Tp, bool _CallIsValid = false>
    static coroutine_handle from_address(_Tp*) {
      static_assert(_CallIsValid,
       "coroutine_handle<promise_type>::from_address cannot be called with "
        "non-void pointers");
    }

    template <bool _CallIsValid = false>
    static coroutine_handle from_address(_Promise*) {
      static_assert(_CallIsValid,
       "coroutine_handle<promise_type>::from_address cannot be used with "
        "pointers to the coroutine's promise type; use 'from_promise' instead");
    }

    _LIBCPP_ALWAYS_INLINE
    static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
        typedef typename remove_cv<_Promise>::type _RawPromise;
        coroutine_handle __tmp;
        __tmp.__handle_ = __builtin_coro_promise(
            _VSTD::addressof(const_cast<_RawPromise&>(__promise)),
             __alignof(_Promise), true);
        return __tmp;
    }
};

struct _LIBCPP_TYPE_VIS suspend_never {
  _LIBCPP_ALWAYS_INLINE
  bool await_ready() const _NOEXCEPT { return true; }
  _LIBCPP_ALWAYS_INLINE
  void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
  _LIBCPP_ALWAYS_INLINE
  void await_resume() const _NOEXCEPT {}
};

struct _LIBCPP_TYPE_VIS suspend_always {
  _LIBCPP_ALWAYS_INLINE
  bool await_ready() const _NOEXCEPT { return false; }
  _LIBCPP_ALWAYS_INLINE
  void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
  _LIBCPP_ALWAYS_INLINE
  void await_resume() const _NOEXCEPT {}
};

_LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp>
struct hash<_VSTD_CORO::coroutine_handle<_Tp> > {
    using __arg_type = _VSTD_CORO::coroutine_handle<_Tp>;
    _LIBCPP_INLINE_VISIBILITY
    size_t operator()(__arg_type const& __v) const _NOEXCEPT
    {return hash<void*>()(__v.address());}
};

_LIBCPP_END_NAMESPACE_STD

#endif // !defined(_LIBCPP_HAS_NO_COROUTINES)

#endif /* _LIBCPP_EXPERIMENTAL_COROUTINE */