weak_ptr::weak_ptr
Constructs a weak_ptr.
weak_ptr();
weak_ptr(const weak_ptr& wp);
template<class Other>
weak_ptr(const weak_ptr<Other>& wp);
template<class Other>
weak_ptr(const shared_ptr<Other>& sp);
Parameters
Other
The type controlled by the argument shared/weak pointer.wp
The weak pointer to copy.sp
The shared pointer to copy.
Remarks
The constructors each construct an object that points to the resource named by the operand sequence.
Example
// std_tr1__memory__weak_ptr_construct.cpp
// compile with: /EHsc
#include <memory>
#include <iostream>
int main()
{
std::weak_ptr<int> wp0;
std::cout << "wp0.expired() == " << std::boolalpha
<< wp0.expired() << std::endl;
std::shared_ptr<int> sp1(new int(5));
std::weak_ptr<int> wp1(sp1);
std::cout << "*wp1.lock() == "
<< *wp1.lock() << std::endl;
std::weak_ptr<int> wp2(wp1);
std::cout << "*wp2.lock() == "
<< *wp2.lock() << std::endl;
return (0);
}
wp0.expired() == true *wp1.lock() == 5 *wp2.lock() == 5
Requirements
Header: <memory>
Namespace: std