operator==,!=,<,<=,>,>=(std::unique_ptr)
来自cppreference.com
< cpp | memory | unique ptr
template<class T1, class D1, class T2, class D2> bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(1) | (C++11 起) |
template<class T1, class D1, class T2, class D2> bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(2) | (C++11 起) |
template<class T1, class D1, class T2, class D2> bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(3) | (C++11 起) |
template<class T1, class D1, class T2, class D2> bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(4) | (C++11 起) |
template<class T1, class D1, class T2, class D2> bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(5) | (C++11 起) |
template<class T1, class D1, class T2, class D2> bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); |
(6) | (C++11 起) |
template <class T, class D> bool operator==(const unique_ptr<T, D>& x, nullptr_t) noexcept; |
(7) | (C++11 起) |
template <class T, class D> bool operator==(nullptr_t, const unique_ptr<T, D>& x) noexcept; |
(8) | (C++11 起) |
template <class T, class D> bool operator!=(const unique_ptr<T, D>& x, nullptr_t) noexcept; |
(9) | (C++11 起) |
template <class T, class D> bool operator!=(nullptr_t, const unique_ptr<T, D>& x) noexcept; |
(10) | (C++11 起) |
template <class T, class D> bool operator<(const unique_ptr<T, D>& x, nullptr_t); |
(11) | (C++11 起) |
template <class T, class D> bool operator<(nullptr_t, const unique_ptr<T, D>& y); |
(12) | (C++11 起) |
template <class T, class D> bool operator<=(const unique_ptr<T, D>& x, nullptr_t); |
(13) | (C++11 起) |
template <class T, class D> bool operator<=(nullptr_t, const unique_ptr<T, D>& y); |
(14) | (C++11 起) |
template <class T, class D> bool operator>(const unique_ptr<T, D>& x, nullptr_t); |
(15) | (C++11 起) |
template <class T, class D> bool operator>(nullptr_t, const unique_ptr<T, D>& y); |
(16) | (C++11 起) |
template <class T, class D> bool operator>=(const unique_ptr<T, D>& x, nullptr_t); |
(17) | (C++11 起) |
template <class T, class D> bool operator>=(nullptr_t, const unique_ptr<T, D>& y); |
(18) | (C++11 起) |
比较二个 unique_ptr
或 unique_ptr
与 nullptr 的指针值。
1-6) 比较二个
unique_ptr
。7-18) 比较
unique_ptr
与 nullptr 。参数
x, y | - | 要比较的 unique_ptr
|
返回值
1) x.get() == y.get()
2) x.get() != y.get()
3) std::less<CT>()(x.get(), y.get()) ,其中 CT
是 std::common_type<unique_ptr<T1, D1>::pointer, unique_ptr<T2, D2>::pointer>::type
4) !(y < x)
5) y < x
6) !(x < y)
7-8) !x
9-10) (bool)x
11) std::less<unique_ptr<T,D>::pointer>()(x.get(), nullptr)
12) std::less<unique_ptr<T,D>::pointer>()(nullptr, y.get())
13) !(nullptr < x)
14) !(y < nullptr)
15) nullptr < x
16) y < nullptr
17) !(x < nullptr)
18) !(nullptr < y)
示例
运行此代码
#include <iostream> #include <memory> int main() { std::unique_ptr<int> p1(new int(42)); std::unique_ptr<int> p2(new int(42)); std::cout << "p1 == p1: " << (p1 == p1) << '\n'; // p1 与 p2 指向不同内存位置,故 p1 != p2 std::cout << "p1 == p2: " << (p1 == p2) << '\n'; }
输出:
p1 == p1: 1 p1 == p2: 0
参阅
返回指向被管理对象的指针 (公开成员函数) |