std::swap(std::shared_ptr)
From cppreference.com
| Defined in header <memory>
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template< class T >
void swap( std::shared_ptr<T>& lhs, std::shared_ptr<T>& rhs ) noexcept;
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(since C++11) (constexpr since C++26) |
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Specializes the std::swap algorithm for std::shared_ptr. Swaps the contents of lhs and rhs. Calls lhs.swap(rhs).
Parameters
| lhs, rhs | - | smart pointers whose contents to swap |
Complexity
Constant.
Example
Run this code
#include <iostream>
#include <memory>
#include <string>
struct Foo
{
Foo(int _val) : val(_val) { std::cout << "Foo...\n"; }
~Foo() { std::cout << "~Foo...\n"; }
std::string print() { return std::to_string(val); }
int val;
};
int main()
{
std::shared_ptr<Foo> p1 = std::make_shared<Foo>(100);
std::shared_ptr<Foo> p2 = std::make_shared<Foo>(200);
auto print = [&]()
{
std::cout << " p1=" << (p1 ? p1->print() : "nullptr");
std::cout << " p2=" << (p2 ? p2->print() : "nullptr") << '\n';
};
print();
std::swap(p1, p2);
print();
p1.reset();
print();
std::swap(p1, p2);
print();
}
Output:
Foo...
Foo...
p1=100 p2=200
p1=200 p2=100
~Foo...
p1=nullptr p2=100
p1=100 p2=nullptr
~Foo...
See also
| swaps the values of two objects (function template) | |
| swaps the contents (public member function) |