std::pair::operator=

 

C++

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Technical Specifications

 

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rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

optional, any and variant (C++17)

optional

any

variant

in_placein_place_typein_place_indexin_place_tin_place_type_tin_place_index_t

Pairs and tuples

pair

tuple (C++11)

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std::pair

Member functions

pair::pair

pair::operator=

pair::swap

Non-member functions

make_pair

operator==operator!=operator<operator<=operator>operator>=

std::swap

get (C++11)

Helper classes

tuple_size (C++11)

tuple_element (C++11)

 

pair& operator=( const pair& other );	(1)
template< class U1, class U2 > pair& operator=( const pair<U1,U2>& other );	(2)
pair& operator=( pair&& other );	(3)	(since C++11)
template< class U1, class U2 > pair& operator=( pair<U1,U2>&& other );	(4)	(since C++11)

Replaces the contents of the pair.

1) Copy assignment operator. Replaces the contents with a copy of the contents of other.

2) Assigns other.first to first and other.second to second

3) Move assignment operator. Replaces the contents with those of other using move semantics.

4) Assigns std::forward<U1>(p.first) to first and std::forward<U2>(p.second) to second.

The behavior of these functions is undefined unless: For (1),std::is_copy_assignable<first_type>::value and std::is_copy_assignable<second_type>::value are both true. For (2),std::is_assignable<first_type&, const U1&>::value and std::is_assignable<second_type&, const U2&>::value are both true. For (3),std::is_move_assignable<first_type>::value and std::is_move_assignable<second_type>::value are both true. For (4),std::is_assignable<first_type&, U1&&>::value and std::is_assignable<second_type&, U2&&>::value are both true.

(until C++17)

These functions do not participate in overload resolution (or, for the copy assignment operator, is defined as deleted) if any required assignment operation is invalid. Specifically: (1) is defined as deleted unless std::is_copy_assignable_v<first_type> and std::is_copy_assignable_v<second_type> are both true. (2) does not participate in overload resolution unless std::is_assignable_v<first_type&, const U1&> and std::is_assignable_v<second_type&, const U2&> are both true. (3) does not participate in overload resolution unless std::is_move_assignable_v<first_type> and std::is_move_assignable_v<second_type> are both true. (4) does not participate in overload resolution unless std::is_assignable_v<first_type&, U1&&> and std::is_assignable_v<second_type&, U2&&> are both true.

(since C++17)

Parameters

other

-

pair of values to replace the contents of this pair

Return value

*this

Exceptions

1-2) (none)

3)

noexcept specification:  

noexcept(

    is_nothrow_move_assignable<T1>::value &&
    is_nothrow_move_assignable<T2>::value

)

4) (none)