std::weak_ptr<T>:: expired

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).

Parameters

(none)

Return value

true if the managed object has already been deleted, false otherwise.

Notes

If the managed object is shared among threads, it is only meaningful when expired() returns true.

Example

#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();
}

gw is valid
gw is expired

See also