std::shared_ptr<T>::~shared_ptr
~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>) |
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