std::is_move_constructible, std::is_trivially_move_constructible, std::is_nothrow_move_constructible

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C++
 
实用工具库
类型的支持 (basic types, RTTI, type traits)
动态内存管理
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程序实用工具
可变参数函数
日期和时间
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initializer_list（C++11）
bitset
hash（C++11）
关系运算符
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Relational operators
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rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
双和元组
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Pairs and tuples
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pair
tuple（C++11）
piecewise_construct_t（C++11）
piecewise_construct（C++11）
掉期，远期和移动
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Swap, forward and move
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swap
forward（C++11）
move（C++11）
move_if_noexcept（C++11）
declval（C++11）
 
类型的支持
基本类型
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Basic types
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基本类型
固定宽度的整数类型 （C++11）
nullptr_t（C++11）
offsetof
NULL
数值范围内
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Numeric limits
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C数字限制接口
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Type traits
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Supported operations
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is_constructible
is_trivially_constructible
is_nothrow_constructible		（C++11）
（C++11）
（C++11）
is_default_constructible
is_trivially_default_constructible
is_nothrow_default_constructible		（C++11）
（C++11）
（C++11）
is_copy_constructible
is_trivially_copy_constructible
is_nothrow_copy_constructible		（C++11）
（C++11）
（C++11）
is_move_constructible
is_trivially_move_constructible
is_nothrow_move_constructible		（C++11）
（C++11）
（C++11）
is_assignable
is_trivially_assignable
is_nothrow_assignable		（C++11）
（C++11）
（C++11）
is_copy_assignable
is_trivially_copy_assignable
is_nothrow_copy_assignable		（C++11）
（C++11）
（C++11）
is_move_assignable
is_trivially_move_assignable
is_nothrow_move_assignable		（C++11）
（C++11）
（C++11）
is_destructible
is_trivially_destructible
is_nothrow_destructible		（C++11）
（C++11）
（C++11）
has_virtual_destructor（C++11）
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remove_const
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add_const
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enable_if（C++11）
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result_of（C++11）
键入特征常数
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Type trait constants
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integral_constant（C++11）
 
Defined in header <type_traits>
template< class T >
struct is_move_constructible;
 (1) （C++11 起）
template< class T >
struct is_trivially_move_constructible;
 (2) （C++11 起）
template< class T >
struct is_nothrow_move_constructible;
 (3) （C++11 起）
1)
检查一个类型是否是MoveConstructible，即有一个可访问的显式或隐式的举动构造函数。如果符合要求，一个成员value等于true，否则value是false.
Original:
Checks whether a type is MoveConstructible, i.e. has an accessible explicit or implicit move constructor. If the requirement is met, a member constant value equal true is provided, otherwise value is false.
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2)
同为1），但此举构造器的表达式不调用任何操作，是不平凡的.
Original:
Same as 1), but the move constructor expression does not call any operation that is not trivial.
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3)
同为1），但这一举措的构造的表达noexcept.
Original:
Same as 1), but the move constructor expression is noexcept.
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目录

Inherited from std::integral_constant

Member constants

value
[静态的] </ SPAN></div></div>
true如果 T is move-constructible ，false其他方式
Original:
true if T is move-constructible , false otherwise
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（公共静态成员常量）

Member functions

operator bool
转换的对象bool，返回value
Original:
converts the object to bool, returns value
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（公共成员函数）

Member types

类型
Original:
Type
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 Definition
value_type bool
type std::integral_constant<bool, value>

</div>

[编辑] 注释

移动构造函数通常noexcept，因为否则的话，他们是无法使用任何代码，提供了强大的异常保证.
Original:
Move constructors are usually noexcept, since otherwise they are unusable in any code that provides strong exception guarantee.
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[编辑] 可能的实现

template<class T>
struct is_move_constructible :
        std::is_constructible<T, typename std::add_rvalue_reference<T>::type> {};
 
template<class T>
struct is_trivially_move_constructible :
       std::is_trivially_constructible<T, typename std::add_rvalue_reference<T>::type> {};
 
template<class T>
struct is_nothrow_move_constructible :
       std::is_nothrow_constructible<T, typename std::add_rvalue_reference<T>::type> {};

[编辑] 为例

#include <iostream>
#include <type_traits>
 
struct Ex1 {
    std::string str; // member has a non-trivial but non-throwing move ctor
};
struct Ex2 {
    int n;
    Ex2(Ex2&&) = default; // trivial and non-throwing
};
 
int main() {
    std::cout << std::boolalpha << "Ex1 is move-constructible? "
              << std::is_move_constructible<Ex1>::value << '\n'
              << "Ex1 is trivially move-constructible? "
              << std::is_trivially_move_constructible<Ex1>::value << '\n'
              << "Ex1 is nothrow move-constructible? "
              << std::is_nothrow_move_constructible<Ex1>::value << '\n'
              << "Ex2 is trivially move-constructible? "
              << std::is_trivially_move_constructible<Ex2>::value << '\n'
              << "Ex2 is nothrow move-constructible? "
              << std::is_nothrow_move_constructible<Ex2>::value << '\n';
}

Output: 

Ex1 is move-constructible? true
Ex1 is trivially move-constructible? false
Ex1 is nothrow move-constructible? true
Ex2 is trivially move-constructible? true
Ex2 is nothrow move-constructible? true

[编辑] 另请参阅

（C++11）
（C++11）
（C++11）
检查如果一个类型有一个构造函数的具体参数
Original:
checks if a type has a constructor for specific arguments
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（类模板） [edit]
（C++11）
（C++11）
（C++11）
检查如果一个类型有一个默认的构造函数
Original:
checks if a type has a default constructor
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（类模板） [edit]
（C++11）
（C++11）
（C++11）
一类的检查，如果有拷贝构造函数
Original:
checks if a type has a copy constructor
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（类模板） [edit]
（C++11）
获得一个右值引用的举动构造方法不抛出
Original:
obtains an rvalue reference if the move constructor does not throw
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（函数模板） [edit]
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/types/is_move_constructible&oldid=27380”