std::owner_less

 

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Smart pointers unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (until C++17*) owner_less (C++11) owner_less<void> (C++17) owner_hash (C++26) owner_equal (C++26) enable_shared_from_this (C++11) bad_weak_ptr (C++11) default_delete (C++11) out_ptr_t (C++23) inout_ptr_t (C++23) Low level memory management operator new operator new[] operator delete operator delete[] get_new_handler (C++11) set_new_handler launder (C++17) bad_alloc bad_array_new_length (C++11) nothrow_t align_val_t (C++17) destroying_delete_t (C++20) new_handler nothrow Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) C Library malloc calloc realloc    aligned_alloc (C++17) free

 

Defined in header <memory>
template<> struct owner_less<void>;		(since C++17)

std::owner_less<void> is a specialization of std::owner_less with parameter types deduced.

Nested types

Nested type	Definition
is_transparent	unspecified

Member functions

operator()

compares its arguments using owner-based semantics (function)

std::owner_less<void>::operator()

template< class T, class U > bool operator()( const std::shared_ptr<T>& lhs,                  const std::shared_ptr<U>& rhs ) const noexcept;		(since C++17)
template< class T, class U > bool operator()( const std::shared_ptr<T>& lhs,                  const std::weak_ptr<U>& rhs ) const noexcept;		(since C++17)
template< class T, class U > bool operator()( const std::weak_ptr<T>& lhs,                  const std::shared_ptr<U>& rhs ) const noexcept;		(since C++17)
template< class T, class U > bool operator()( const std::weak_ptr<T>& lhs,                  const std::weak_ptr<U>& rhs ) const noexcept;		(since C++17)

Compares lhs and rhs using owner-based semantics. Effectively calls lhs.owner_before(rhs).

The ordering is strict weak ordering relation.

lhs and rhs are equivalent only if they are both empty or share ownership.

Parameters

lhs, rhs

-

shared-ownership pointers to compare

Return value

true if lhs is less than rhs as determined by the owner-based ordering.

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_transparent_operators	201510L	(C++17)	Transparent std::owner_less (std::owner_less<void>)

See also

owner_before	provides owner-based ordering of shared pointers (public member function of std::shared_ptr<T>)
owner_before	provides owner-based ordering of weak pointers (public member function of std::weak_ptr<T>)