std::weak_ptr<T>::expired
From cppreference.com
bool expired() const noexcept; |
(since C++11) | |
Equivalent to use_count() == 0. The destructor for the managed object may not yet have been called, but this object's destruction is imminent (or may have already happened).
Contents |
[edit] Parameters
(none)
[edit] Return value
true if the managed object has already been deleted, false otherwise.
[edit] Notes
If the managed object is shared among threads, it is only meaningful when expired()
returns true.
[edit] Example
Demonstrates how expired
is used to check validity of the pointer.
Run this code
#include <iostream> #include <memory> std::weak_ptr<int> gw; void f() { if (!gw.expired()) std::cout << "gw is valid\n"; else std::cout << "gw is expired\n"; } int main() { { auto sp = std::make_shared<int>(42); gw = sp; f(); } f(); }
Output:
gw is valid gw is expired
[edit] See also
creates a shared_ptr that manages the referenced object (public member function) | |
returns the number of shared_ptr objects that manage the object (public member function) |