llvm-project/libcxx/include/__nullptr

63 lines
1.6 KiB
C++

// -*- C++ -*-
//===--------------------------- __nullptr --------------------------------===//
//
// 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_NULLPTR
#define _LIBCPP_NULLPTR
#include <__config>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
#ifdef _LIBCPP_HAS_NO_NULLPTR
_LIBCPP_BEGIN_NAMESPACE_STD
struct _LIBCPP_TEMPLATE_VIS nullptr_t
{
void* __lx;
struct __nat {int __for_bool_;};
_LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t() : __lx(0) {}
_LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t(int __nat::*) : __lx(0) {}
_LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR operator int __nat::*() const {return 0;}
template <class _Tp>
_LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR
operator _Tp* () const {return 0;}
template <class _Tp, class _Up>
_LIBCPP_ALWAYS_INLINE
operator _Tp _Up::* () const {return 0;}
friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator==(nullptr_t, nullptr_t) {return true;}
friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator!=(nullptr_t, nullptr_t) {return false;}
};
inline _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t __get_nullptr_t() {return nullptr_t(0);}
#define nullptr _VSTD::__get_nullptr_t()
_LIBCPP_END_NAMESPACE_STD
#else // _LIBCPP_HAS_NO_NULLPTR
namespace std
{
typedef decltype(nullptr) nullptr_t;
}
#endif // _LIBCPP_HAS_NO_NULLPTR
#endif // _LIBCPP_NULLPTR