std::shared_ptr<T>::~shared_ptr
From cppreference.com
< cpp | memory | shared ptr
| ~shared_ptr(); |
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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.
[edit] Notes
Unlike std::unique_ptr, the deleter of std::shared_ptr is invoked even if the managed pointer is null.
[edit] Example
Run this code
#include <iostream> #include <memory> 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()
[edit] See also
destroys a weak_ptr (public member function of std::weak_ptr<T>)
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