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std::enable_shared_from_this::shared_from_this

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< cpp‎ | memory‎ | enable shared from this
Revision as of 22:12, 31 May 2013 by P12bot (Talk | contribs)

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shared_ptr<T> shared_from_this();
(1)
shared_ptr<T const> shared_from_this() const;
(2)

Returns a std::shared_ptr<T> that shares ownership of *this with all existing std::shared_ptr<T> that refer to *this.

Contents

[edit] Notes

Before calling shared_from_this, there should be at least one std::shared_ptr<T> p that owns *this.

[edit] Return value

std::shared_ptr<T> that shares ownership of *this with pre-existing std::shared_ptr<T>s

[edit] Example

#include <iostream>
#include <memory>
 
struct Foo : public std::enable_shared_from_this<Foo> {
    Foo() { std::cout << "Foo::Foo\n"; }
    ~Foo() { std::cout << "Foo::~Foo\n"; } 
    std::shared_ptr<Foo> getFoo() { return shared_from_this(); }
};
 
int main() {
    Foo *f = new Foo;
    std::shared_ptr<Foo> pf1;
 
    {
        std::shared_ptr<Foo> pf2(f);
        pf1 = pf2->getFoo();  // shares ownership of object with pf2
    }
 
    std::cout << "pf2 is gone\n";   
}

Output:

Foo::Foo
pf2 is gone
Foo::~Foo

[edit] See also

smart pointer with shared object ownership semantics
(class template) [edit]