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std::is_pointer

STD：：是[医]指针

Defined in header ​​
template< class T > struct is_pointer;​(since C++11)

检查是否T是指向对象的指针或指向函数%28的指针，但不是指向成员/成员函数%29的指针。提供成员常量。value等于true，如果T对象/函数指针类型。否则，value等于false...

模板参数

T-a type to check

辅助变量模板

template< class T > inline constexpr bool is_pointer_v = is_pointer::value;​(since C++17)

继承自STD：积分[医]常量

成员常数

value statictrue if T is a pointer type , false otherwise (public static member constant)

成员函数

operator boolconverts the object to bool, returns value (public member function)
operator() (C++14)returns value (public member function)

成员类型

TypeDefinition
value_typebool
typestd::integral_constant<bool, value>

可能的实施

模板<class T>结构是[医]指针[医]助手：std：：false[医]类型{}；模板<class T>结构是[医]指针[医]助手<T%2A>：STD：：真[医]类型{}；模板<class T>结构是[医]指针：是[医]指针[医]助手<type Name STD：：Remove[医]CV<T>*类型>{}；

*。

例

二次

#include <iostream>
#include <type_traits>
 
class A {};
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_pointer<A>::value << '\n';
    std::cout << std::is_pointer<A *>::value << '\n';
    std::cout << std::is_pointer<A &>::value << '\n';
    std::cout << std::is_pointer<int>::value << '\n';
    std::cout << std::is_pointer<int *>::value << '\n';
    std::cout << std::is_pointer<int **>::value << '\n';
    std::cout << std::is_pointer<int[10]>::value << '\n';
    std::cout << std::is_pointer<std::nullptr_t>::value << '\n';
}

二次

产出：

二次

false
true
false
false
true
true
false
false

二次

另见

is_member_pointer (C++11)checks if a type is a pointer to a non-static member function or object (class template)
is_member_object_pointer (C++11)checks if a type is a pointer to a non-static member object (class template)
is_member_function_pointer (C++11)checks if a type is a pointer to a non-static member function (class template)
is_array (C++11)checks if a type is an array type (class template)
is_scalar (C++11)checks if a type is scalar type (class template)

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http：//en.cppreference.com/w/cpp/type/is[医]指针

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