operator==,!=,<,<=,>,>=,<=>(std::unique_ptr)

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)
Dynamic memory management
Error handling
Program utilities
Variadic functions
Library feature-test macros
Date and time
Function objects
Formatting library (C++20)
initializer_list (C++11)
source_location (C++20)
bitset
hash (C++11)
integer_sequence (C++14)
Relational operators (deprecated in C++20)
rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
Comparisons (C++20)
three_way_comparablethree_way_comparable_with
strong_ordering weak_ordering partial_ordering common_comparison_category compare_three_way_result compare_three_way	strong_order weak_order partial_order compare_strong_order_fallback compare_weak_order_fallback compare_partial_order_fallback	is_eqis_neqis_ltis_lteqis_gtis_gteq
Common vocabulary types
pair tuple (C++11) apply (C++17) make_from_tuple (C++17)	optional (C++17) any (C++17) variant (C++17)
Swap, forward and move
swap
exchange (C++14)
forward (C++11)
move (C++11)
move_if_noexcept (C++11)
Elementary string conversions
to_chars (C++17)
from_chars (C++17)
chars_format (C++17)
Type operations
declval (C++11)
as_const (C++17)
launder (C++17)

 

Dynamic memory management

Smart pointers unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (until C++17) owner_less (C++11) enable_shared_from_this (C++11) bad_weak_ptr (C++11) default_delete (C++11) Allocators allocator allocator_traits (C++11) allocator_arg_t (C++11) 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) scoped_allocator_adaptor (C++11) pmr::polymorphic_allocator (C++17) 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::null_memory_resource (C++17) pmr::synchronized_pool_resource (C++17) pmr::unsynchronized_pool_resource (C++17) pmr::monotonic_buffer_resource (C++17) pmr::pool_options (C++17)

Uninitialized storage uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) destroy_at (C++17) uninitialized_copy_n (C++11) uninitialized_fill_n uninitialized_move_n (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17) destroy_n (C++17) construct_at (C++20) raw_storage_iterator (until C++20) get_temporary_buffer (until C++20) return_temporary_buffer (until C++20) Garbage collection support declare_reachable (C++11) undeclare_reachable (C++11) declare_no_pointers (C++11) undeclare_no_pointers (C++11) pointer_safety (C++11) get_pointer_safety (C++11) Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) C Library malloc aligned_alloc (C++17) calloc realloc free Low level memory management

 

std::unique_ptr

Member functions

unique_ptr::unique_ptr

unique_ptr::~unique_ptr

unique_ptr::operator=

Modifiers

unique_ptr::release

unique_ptr::reset

unique_ptr::swap

Observers

unique_ptr::get

unique_ptr::get_deleter

unique_ptr::operator bool

unique_ptr::operator*unique_ptr::operator->

unique_ptr::operator[]

Non-member functions

make_uniquemake_unique_for_overwrite (C++14)(C++20)

operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(C++20)

operator<< (C++20)

std::swap

std::hash

 

template<class T1, class D1, class T2, class D2> bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(1)	(since C++11)
template<class T1, class D1, class T2, class D2> bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(2)	(since C++11) (until C++20)
template<class T1, class D1, class T2, class D2> bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(3)	(since C++11)
template<class T1, class D1, class T2, class D2> bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(4)	(since C++11)
template<class T1, class D1, class T2, class D2> bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(5)	(since C++11)
template<class T1, class D1, class T2, class D2> bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(6)	(since C++11)
template<class T1, class D1, class T2, class D2>     requires std::three_way_comparable_with<         typename unique_ptr<T1, D1>::pointer,         typename unique_ptr<T2, D2>::pointer> std::compare_three_way_result_t<typename unique_ptr<T1, D1>::pointer,                                 typename unique_ptr<T2, D2>::pointer>     operator<=>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);	(7)	(since C++20)
template <class T, class D> bool operator==(const unique_ptr<T, D>& x, std::nullptr_t) noexcept;	(8)	(since C++11)
template <class T, class D> bool operator==(std::nullptr_t, const unique_ptr<T, D>& x) noexcept;	(9)	(since C++11) (until C++20)
template <class T, class D> bool operator!=(const unique_ptr<T, D>& x, std::nullptr_t) noexcept;	(10)	(since C++11) (until C++20)
template <class T, class D> bool operator!=(std::nullptr_t, const unique_ptr<T, D>& x) noexcept;	(11)	(since C++11) (until C++20)
template <class T, class D> bool operator<(const unique_ptr<T, D>& x, std::nullptr_t);	(12)	(since C++11)
template <class T, class D> bool operator<(std::nullptr_t, const unique_ptr<T, D>& y);	(13)	(since C++11)
template <class T, class D> bool operator<=(const unique_ptr<T, D>& x, std::nullptr_t);	(14)	(since C++11)
template <class T, class D> bool operator<=(std::nullptr_t, const unique_ptr<T, D>& y);	(15)	(since C++11)
template <class T, class D> bool operator>(const unique_ptr<T, D>& x, std::nullptr_t);	(16)	(since C++11)
template <class T, class D> bool operator>(std::nullptr_t, const unique_ptr<T, D>& y);	(17)	(since C++11)
template <class T, class D> bool operator>=(const unique_ptr<T, D>& x, std::nullptr_t);	(18)	(since C++11)
template <class T, class D> bool operator>=(std::nullptr_t, const unique_ptr<T, D>& y);	(19)	(since C++11)
template<class T, class D>     requires std::three_way_comparable_with<         typename unique_ptr<T, D>::pointer,         std::nullptr_t> std::compare_three_way_result_t<typename unique_ptr<T, D>::pointer,                                 std::nullptr_t>     operator<=>(const unique_ptr<T, D>& x, std::nullptr_t);	(20)	(since C++20)

Compares the pointer values of two unique_ptrs, or a unique_ptr and nullptr.

1-7) Compares two unique_ptrs

8-20) Compares a unique_ptr and nullptr.

Parameters

x, y

-

unique_ptrs to compare

Return value

1) x.get() == y.get()

2) x.get() != y.get()

3) std::less<CT>()(x.get(), y.get()), where CT is std::common_type<unique_ptr<T1, D1>::pointer, unique_ptr<T2, D2>::pointer>::type

4) !(y < x)

5) y < x

6) !(x < y)

7) std::compare_three_way{}(x.get(), y.get())

8-9) !x

10-11) (bool)x

12) std::less<unique_ptr<T,D>::pointer>()(x.get(), nullptr)

13) std::less<unique_ptr<T,D>::pointer>()(nullptr, y.get())

14) !(nullptr < x)

15) !(y < nullptr)

16) nullptr < x

17) y < nullptr

18) !(x < nullptr)

19) !(nullptr < y)

20) std::compare_three_way{}(x.get(), nullptr)

Example

Run this code

#include <iostream>
#include <memory>
 
int main() 
{
    std::unique_ptr<int> p1(new int(42));
    std::unique_ptr<int> p2(new int(42));
 
    std::cout << "p1 == p1: " << (p1 == p1) << '\n';
 
    // p1 and p2 point to different memory locations, so p1 != p2
    std::cout << "p1 == p2: " << (p1 == p2) << '\n';
}

Output:

p1 == p1: 1
p1 == p2: 0

See also

get	returns a pointer to the managed object (public member function)