std::is_base_of

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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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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>
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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）
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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
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C数字限制接口
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Type traits
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Type properties
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支持的操作
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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）
关系和属性查询
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Relationships and property queries
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is_same（C++11）
is_base_of（C++11）
is_convertible（C++11）
alignment_of（C++11）
rank（C++11）
extent（C++11）
类型的修改
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Type modifications
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remove_cv
remove_const
remove_volatile		（C++11）
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（C++11）
add_cv
add_const
add_volatile		（C++11）
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（C++11）
make_signed（C++11）
make_unsigned（C++11）
remove_reference（C++11）
add_lvalue_reference
add_rvalue_reference		（C++11）
（C++11）
remove_pointer（C++11）
add_pointer（C++11）
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remove_all_extents（C++11）
类型转换
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Type transformations
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aligned_storage（C++11）
aligned_union（C++11）
decay（C++11）
enable_if（C++11）
conditional（C++11）
common_type（C++11）
underlying_type（C++11）
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 B, class D >
struct is_base_of;
 （C++11 起）
如果D是来自B或者如果两者是相同的非工会类，成员常量value等于true。否则value是false.
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If D is derived from B or if both are the same non-union class, provides the member constant value equal to true. Otherwise value is false.
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目录

Inherited from std::integral_constant

Member constants

value
[静态的] </ SPAN></div></div>
true如果 D is derived from B ，false其他方式
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true if D is derived from B , 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
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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>

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[编辑] 为例

#include <iostream>
#include <type_traits>
 
class A {};
 
class B : A {};
 
class C {};
 
int main()
{
    std::cout << std::boolalpha;
    std::cout << "a2b: " << std::is_base_of<A, B>::value << '\n';
    std::cout << "b2a: " << std::is_base_of<B, A>::value << '\n';
    std::cout << "c2b: " << std::is_base_of<C, B>::value << '\n';
}

Output: 

a2b: true
b2a: false
c2b: false
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/types/is_base_of&oldid=27564”