operator==, <=>(std::indirect)

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Memory management library

voidify (exposition only*) Allocators allocator allocator_traits (C++11) allocation_result (C++23) scoped_allocator_adaptor (C++11) pmr::polymorphic_allocator (C++17) allocator_arg (C++11) uses_allocator (C++11) uses_allocator_construction_args (C++20) make_obj_using_allocator (C++20) uninitialized_construct_using_allocator (C++20) Uninitialized memory algorithms uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_copy_n (C++11) uninitialized_fill_n uninitialized_move_n (C++17) construct_at (C++20) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17) destroy_n (C++17) destroy_at (C++17) Constrained uninitialized memory algorithms ranges::uninitialized_copy (C++20) ranges::uninitialized_fill (C++20) ranges::uninitialized_move (C++20) ranges::uninitialized_copy_n (C++20)  ranges::uninitialized_fill_n (C++20) ranges::uninitialized_move_n (C++20) ranges::construct_at (C++20) ranges::uninitialized_default_construct (C++20) ranges::uninitialized_value_construct (C++20) ranges::destroy (C++20) ranges::uninitialized_default_construct_n (C++20)  ranges::uninitialized_value_construct_n (C++20) ranges::destroy_n (C++20) ranges::destroy_at (C++20) Memory resources pmr::memory_resource (C++17) pmr::get_default_resource (C++17) pmr::set_default_resource (C++17) pmr::new_delete_resource (C++17) pmr::pool_options (C++17) pmr::null_memory_resource (C++17) pmr::synchronized_pool_resource (C++17) pmr::unsynchronized_pool_resource (C++17) pmr::monotonic_buffer_resource (C++17) Explicit lifetime management start_lifetime_as (C++23) start_lifetime_as_array (C++23) Types for composite class design indirect (C++26) polymorphic (C++26) Uninitialized storage (until C++20) raw_storage_iterator (until C++20*) get_temporary_buffer (until C++20*) return_temporary_buffer (until C++20*) Garbage collector support (until C++23) declare_reachable (C++11)(until C++23) declare_no_pointers (C++11)(until C++23) pointer_safety (C++11)(until C++23) undeclare_reachable (C++11)(until C++23) undeclare_no_pointers (C++11)(until C++23) get_pointer_safety (C++11)(until C++23)

Low level memory management operator newoperator new[] operator deleteoperator delete[] nothrow_t nothrow new_handler set_new_handler get_new_handler (C++11) bad_alloc bad_array_new_length (C++11) align_val_t (C++17) destroying_delete_t (C++20) launder (C++17) 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) Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) is_sufficiently_aligned (C++26) C Library malloc calloc realloc free aligned_alloc (C++17)

 

std::indirect

Member functions

indirect::indirect

indirect::~indirect

indirect::operator=

Observers

indirect::operator->indirect::operator*

indirect::valueless_after_move

indirect::get_allocator

Modifiers

indirect::swap

Non-member functions

operator==operator<=>

swap(std::indirect)

Deduction guides

Helper classes

hash<std::indirect>

 

Defined in header <memory>
Compare two indirect objects
template< class U, class A > constexpr bool operator==( const indirect& lhs, const indirect<U, A>& rhs ) noexcept(noexcept(*lhs == *rhs));	(1)	(since C++26)
template< class U, class A > constexpr /*synth-three-way-result*/<T, U> operator<=>( const indirect& lhs, const indirect<U, A>& rhs );	(2)	(since C++26)
Compare an indirect object with a value
template< class U > constexpr bool operator==( const indirect& ind, const U& value ) noexcept(noexcept(*lhs == value));	(3)	(since C++26)
template< class U > constexpr /*synth-three-way-result*/<T, U> operator<=>( const indirect& ind, const U& value );	(4)	(since C++26)

Performs comparison operations on indirect objects.

For the definition of /*synth-three-way-result*/, see synth-three-way-result .

1,2) Compares two indirect objects, the comparison result is defined as follows:

lhs	valueless		not valueless
rhs	valueless	not valueless	valueless	not valueless
operator==	true	false	false	*lhs == *rhs
operator<=>	!lhs.valueless_after_move() <=> !rhs.valueless_after_move()			synth-three-way     (*lhs, *rhs)

1) If the expression *lhs == *rhs is ill-formed or its result is not convertible to bool, the program is ill-formed.

3,4) Compare an indirect object with a value, the comparison result is defined as follows:

Operator	ind is valueless	ind is not valueless
operator==	false	*ind == value
operator<=>	std::strong_ordering::less	synth-three-way (*ind, value)

3) If the expression *ind == value is ill-formed or its result is not convertible to bool, the program is ill-formed.

Parameters

lhs, rhs, ind	-	an indirect object to compare
value	-	value to compare to the owned value

Return value

As described above.

Example