[cfe-dev] Libcxx marco using question

罗勇刚(Yonggang Luo) luoyonggang at gmail.com
Thu Sep 9 04:09:16 PDT 2010


Index: type_traits
===================================================================
--- type_traits	(revision 113464)
+++ type_traits	(working copy)
@@ -264,28 +264,32 @@
 template <class _Tp> struct is_reference<_Tp&&> : public true_type {};
 #endif

+#if defined(__clang__) || (__GNUC__ > 4) || (__GNUC__==4 && __GNUC_MINOR__ >=3)
+#define _LIBCPP_HAS_TYPE_TRAITS
+#endif
+
 // is_union

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_union
     : public integral_constant<bool, __is_union(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct __libcpp_union : public false_type {};
 template <class _Tp> struct is_union : public __libcpp_union<typename
remove_cv<_Tp>::type> {};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // is_class

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_class
     : public integral_constant<bool, __is_class(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 namespace __is_class_imp
 {
@@ -296,7 +300,7 @@
 template <class _Tp> struct is_class
     : public integral_constant<bool,
sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value>
{};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // is_function

@@ -342,12 +346,12 @@

 // is_enum

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_enum
     : public integral_constant<bool, __is_enum(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_enum
     : public integral_constant<bool, !is_void<_Tp>::value             &&
@@ -361,7 +365,7 @@
                                      !is_class<_Tp>::value            &&
                                      !is_function<_Tp>::value         > {};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // is_arithmetic

@@ -742,12 +746,12 @@

 // has_trivial_default_constructor

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_default_constructor
     : public integral_constant<bool, __has_trivial_constructor(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct __has_trivial_default_constructor
     : public integral_constant<bool, is_scalar<_Tp>::value> {};
@@ -755,94 +759,92 @@
 template <class _Tp> struct has_trivial_default_constructor
     : public __has_trivial_default_constructor<typename
remove_all_extents<_Tp>::type> {};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // has_nothrow_default_constructor

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_default_constructor
     : public integral_constant<bool, __has_nothrow_constructor(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_default_constructor
     : public has_trivial_default_constructor<_Tp> {};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // has_trivial_copy_constructor

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_copy_constructor
     : public integral_constant<bool, __has_trivial_copy(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_copy_constructor
     : public integral_constant<bool, is_scalar<_Tp>::value ||
                                      is_reference<_Tp>::value> {};

+#endif  // _LIBCPP_HAS_TYPE_TRAITS

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
-
 // has_nothrow_copy_constructor

-#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_copy_constructor
     : public integral_constant<bool, __has_nothrow_copy(_Tp)> {};

-#else  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_copy_constructor
     : public has_trivial_copy_constructor<_Tp> {};

-#endif  // __GNUC__ >= 4 && __GNUC_MINOR__ >= 3 || defined(__clang__)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

-
 // has_nothrow_move_constructor

 template <class _Tp> struct has_nothrow_move_constructor : public
has_nothrow_copy_constructor<_Tp> {};

 // has_trivial_copy_assign

-#if defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_copy_assign
     : public integral_constant<bool, __has_trivial_assign(_Tp)> {};

-#else
+#else // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_copy_assign
     : public integral_constant<bool, is_scalar<_Tp>::value &&
                                     !is_const<_Tp>::value> {};

-#endif  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // has_nothrow_copy_assign

-#if defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_copy_assign
     : public integral_constant<bool, __has_nothrow_assign(_Tp)> {};

-#else  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_nothrow_copy_assign
     : public has_trivial_copy_assign<_Tp> {};

-#endif  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // has_trivial_destructor

-#if defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_trivial_destructor
     : public integral_constant<bool, __has_trivial_destructor(_Tp)> {};

-#else  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct __libcpp_trivial_destructor
     : public integral_constant<bool, is_scalar<_Tp>::value ||
@@ -851,36 +853,36 @@
 template <class _Tp> struct has_trivial_destructor
     : public __libcpp_trivial_destructor<typename
remove_all_extents<_Tp>::type> {};

-#endif  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // has_virtual_destructor

-#if defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_virtual_destructor
     : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};

-#else  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct has_virtual_destructor : public false_type {};

-#endif  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // is_pod

-#if defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#ifdef _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_pod
     : public integral_constant<bool, __is_pod(_Tp)> {};

-#else  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#else  // _LIBCPP_HAS_TYPE_TRAITS

 template <class _Tp> struct is_pod : public integral_constant<bool,
has_trivial_default_constructor<_Tp>::value   &&

has_trivial_copy_constructor<_Tp>::value      &&

has_trivial_copy_assign<_Tp>::value    &&

has_trivial_destructor<_Tp>::value> {};

-#endif  // defined(__clang__) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
+#endif  // _LIBCPP_HAS_TYPE_TRAITS

 // alignment_of



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