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c++之std::remove_pointer

news 2025/9/17 10:38:13

该函数是一个模板函数，移除T类型的指针类型，如果T类型不是指针，那么去除的类型与T类型相同。

语法：

#include <type_traits>template <class T>
using remove_pointer_t = typename std::remove_pointer<T>::type;

#include <type_traits>
#include <iostream>int main() {
// Example 1: Removing pointer qualifiers
static_assert(std::is_same_v<std::remove_pointer_t<int*>, int>, "int* becomes int");
static_assert(std::is_same_v<std::remove_pointer_t<int**>, int*>, "int** becomes int*");
static_assert(std::is_same_v<std::remove_pointer_t<int>, int>, "int remains int");// Example 2: Using with const and volatile pointers
static_assert(std::is_same_v<std::remove_pointer_t<const int*>, int>, "const int* becomes int");
static_assert(std::is_same_v<std::remove_pointer_t<int* const>, int>, "int* const becomes int");// Example 3: Practical application
int value = 42;
int* ptr = &value;
std::remove_pointer_t<int*> dereferenced_value = *ptr; // deduces to int
std::cout << "Dereferenced value: " << dereferenced_value << std::endl;return 0;
}

实际应用：

模板编程：它通常用于泛型编程，用于推断指针的基本类型并对其进行操作。

智能指针：使用 std:：unique_ptr 或 std:：shared_ptr 时，std:：remove_pointer_t 可以帮助确定智能指针管理的基础类型。

自定义删除器：在使用自定义删除器的场景中，std:：remove_pointer_t 确保为资源管理推导出正确的类型。

#include <memory>
#include <type_traits>
#include <iostream>void custom_deleter(int* ptr) {
std::cout << "Deleting pointer: " << ptr << std::endl;
delete ptr;
}int main() {
std::unique_ptr<std::remove_pointer_t<int*>, decltype(&custom_deleter)> smart_ptr(new int(10), custom_deleter);
std::cout << "Value: " << *smart_ptr << std::endl;return 0;
}