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std::function<R(Args...)>:: swap

From cppreference.net
C++
Utilities library
Function objects
Function invocation
(C++17) (C++23)
Identity function object
(C++20)
Old binders and adaptors
( until C++17* )
( until C++17* )
( until C++17* )
( until C++17* )
( until C++17* )
( until C++17* )
( until C++17* ) ( until C++17* ) ( until C++17* ) ( until C++17* )
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( until C++17* )
( until C++17* ) ( until C++17* ) ( until C++17* ) ( until C++17* )
( until C++20* )
( until C++20* )
std::function
void swap ( function & other ) noexcept ;
(自 C++11 起)

交换 * this 与 other 所存储的可调用对象。

目录

参数

其他 - 用于交换存储的可调用对象的函数包装器

返回值

(无)

示例

运行此代码 
#include <functional>
#include <iostream>
void foo(const char* str, int x)
{
    std::cout << "foo(\"" << str << "\", " << x << ")\n";
}
void bar(const char* str, int x)
{
    std::cout << "bar(\"" << str << "\", " << x << ")\n";
}
int main()
{
    std::function<void(const char*, int)> f1{foo};
    std::function<void(const char*, int)> f2{bar};
    f1("f1", 1);
    f2("f2", 2);
    std::cout << "f1.swap(f2);\n";
    f1.swap(f2);
    f1("f1", 1);
    f2("f2", 2);
}

输出： 

foo("f1", 1)
bar("f2", 2)
f1.swap(f2);
bar("f1", 1)
foo("f2", 2)

参见

交换两个 std::move_only_function 对象的目标
( std::move_only_function 的公开成员函数)