std::shared_ptr<T>::~shared_ptr

From cppreference.com
< cpp‎ | memory‎ | shared ptr
 
 
Utilities library
General utilities
Date and time
Function objects
Formatting library (C++20)
(C++11)
Relational operators (deprecated in C++20)
Integer comparison functions
(C++20)(C++20)(C++20)   
(C++20)
Swap and type operations
(C++14)
(C++11)
(C++11)
(C++11)
(C++17)
Common vocabulary types
(C++11)
(C++17)
(C++17)
(C++17)
(C++11)
(C++17)
(C++23)
Elementary string conversions
(C++17)
(C++17)
 
Dynamic memory management
Uninitialized memory algorithms
Constrained uninitialized memory algorithms
Allocators
Garbage collection support
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)



 
 
~shared_ptr();

If *this owns an object and it is the last shared_ptr owning it, the object is destroyed through the owned deleter.

After the destruction, the smart pointers that shared ownership with *this, if any, will report a use_count() that is one less than its previous value.

Notes

Unlike std::unique_ptr, the deleter of std::shared_ptr is invoked even if the managed pointer is null.

Example

#include <memory>
#include <iostream>
 
struct S {
    S() { std::cout << "S::S()\n"; }
    ~S() { std::cout << "S::~S()\n"; }
    struct Deleter {
        void operator()(S* s) const {
            std::cout << "S::Deleter()\n";
            delete s;
        }
    };
};
 
int main()
{
    auto sp = std::shared_ptr<S>{ new S, S::Deleter{} };
 
    auto use_count = [&sp](char c) {
        std::cout << c << ") use_count(): " << sp.use_count() << '\n';
    };
 
    use_count('A');
    {
        auto sp2 = sp;
        use_count('B');
        {
            auto sp3 = sp;
            use_count('C');
        }
        use_count('D');
    }
    use_count('E');
 
//  sp.reset();
//  use_count('F'); // would print "F) use_count(): 0"
}

Output:

S::S()
A) use_count(): 1
B) use_count(): 2
C) use_count(): 3
D) use_count(): 2
E) use_count(): 1
S::Deleter()
S::~S()

See also

destroys a weak_ptr
(public member function of std::weak_ptr<T>)