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      1 // -*- C++ -*-
      2 //===--------------------------- cstddef ----------------------------------===//
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is dual licensed under the MIT and the University of Illinois Open
      7 // Source Licenses. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #ifndef _LIBCPP_CSTDDEF
     12 #define _LIBCPP_CSTDDEF
     13 
     14 /*
     15     cstddef synopsis
     16 
     17 Macros:
     18 
     19     offsetof(type,member-designator)
     20     NULL
     21 
     22 namespace std
     23 {
     24 
     25 Types:
     26 
     27     ptrdiff_t
     28     size_t
     29     max_align_t
     30     nullptr_t
     31 
     32 }  // std
     33 
     34 */
     35 
     36 #include <__config>
     37 
     38 #include <stddef.h>
     39 
     40 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     41 #pragma GCC system_header
     42 #endif
     43 
     44 _LIBCPP_BEGIN_NAMESPACE_STD
     45 
     46 using ::ptrdiff_t;
     47 using ::size_t;
     48 
     49 #if defined(__CLANG_MAX_ALIGN_T_DEFINED) || defined(_GCC_MAX_ALIGN_T)
     50 // Re-use the compiler's <stddef.h> max_align_t where possible.
     51 using ::max_align_t;
     52 #else
     53 typedef long double max_align_t;
     54 #endif
     55 
     56 #ifdef _LIBCPP_HAS_NO_NULLPTR
     57 
     58 struct _LIBCPP_TYPE_VIS_ONLY nullptr_t
     59 {
     60     void* __lx;
     61 
     62     struct __nat {int __for_bool_;};
     63 
     64     _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t() : __lx(0) {}
     65     _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t(int __nat::*) : __lx(0) {}
     66 
     67     _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR operator int __nat::*() const {return 0;}
     68 
     69     template <class _Tp>
     70         _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR
     71         operator _Tp* () const {return 0;}
     72 
     73     template <class _Tp, class _Up>
     74         _LIBCPP_ALWAYS_INLINE
     75         operator _Tp _Up::* () const {return 0;}
     76 
     77     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator==(nullptr_t, nullptr_t) {return true;}
     78     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator!=(nullptr_t, nullptr_t) {return false;}
     79     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator<(nullptr_t, nullptr_t) {return false;}
     80     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator<=(nullptr_t, nullptr_t) {return true;}
     81     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator>(nullptr_t, nullptr_t) {return false;}
     82     friend _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR bool operator>=(nullptr_t, nullptr_t) {return true;}
     83 };
     84 
     85 inline _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR nullptr_t __get_nullptr_t() {return nullptr_t(0);}
     86 
     87 #define nullptr _VSTD::__get_nullptr_t()
     88 
     89 #endif  // _LIBCPP_HAS_NO_NULLPTR
     90 
     91 _LIBCPP_END_NAMESPACE_STD
     92 
     93 #ifndef _LIBCPP_HAS_NO_NULLPTR
     94 
     95 namespace std
     96 {
     97     typedef decltype(nullptr) nullptr_t;
     98 }
     99 
    100 #endif  // _LIBCPP_HAS_NO_NULLPTR
    101 
    102 #endif  // _LIBCPP_CSTDDEF
    103