NAME

std::weak_ptr::owner_equal - std::weak_ptr::owner_equal

Synopsis

template< class Y > (1) (since C++26)
bool owner_equal( const std::weak_ptr<Y>& other ) const noexcept;
template< class Y >
bool owner_equal( const std::shared_ptr<Y>& other ) const (2) (since C++26)
noexcept;

Checks whether this weak_ptr and other share ownership or are both empty. The
comparison is such that two smart pointers compare equivalent only if they are both
empty or if they both own the same object, even if the values of the pointers
obtained by get() are different (e.g. because they point at different subobjects
within the same object).

The member function owner_equal is an equivalence relation such that
!owner_before(other) && !other.owner_before(*this) is true if and only if
owner_equal(other) is true.

This ordering is used to make shared and weak pointers usable as keys in unordered
associative containers, typically through std::owner_equal.

Parameters

other - the std::shared_ptr or std::weak_ptr to be compared

Return value

true if *this and other share ownership or are both empty. Otherwise, returns false.

Notes

Feature-test macro Value Std Feature
Enabling the use of std::weak_ptr
__cpp_lib_smart_ptr_owner_equality 202306L (C++26) as keys in unordered associative
containers

Example

This section is incomplete
Reason: example

See also

owner_equal provides mixed-type owner-based equal comparisons of shared and weak
(C++26) pointers
(class)

Category:

* Todo with reason