Difference between revisions of "cpp/utility/pair/operator="
From cppreference.com
(merge noexcept) |
(P1032R1) |
||
| Line 2: | Line 2: | ||
{{cpp/utility/pair/navbar}} | {{cpp/utility/pair/navbar}} | ||
{{dcl begin}} | {{dcl begin}} | ||
| − | {{dcl | num=1 | | + | {{dcl rev multi|num=1|dcl1= |
pair& operator=( const pair& other ); | pair& operator=( const pair& other ); | ||
| + | |since2=c++20|dcl2= | ||
| + | constexpr pair& operator=( const pair& other ); | ||
}} | }} | ||
| − | {{dcl | num=2 | | + | {{dcl rev multi|num=2|dcl1= |
template< class U1, class U2 > | template< class U1, class U2 > | ||
pair& operator=( const pair<U1,U2>& other ); | pair& operator=( const pair<U1,U2>& other ); | ||
| + | |since2=c++20|dcl2= | ||
| + | template< class U1, class U2 > | ||
| + | constexpr pair& operator=( const pair<U1,U2>& other ); | ||
}} | }} | ||
| − | {{dcl | num=3 | | + | {{dcl rev multi|num=3|since1=c++11|dcl1= |
pair& operator=( pair&& other ) noexcept(/* see below */); | pair& operator=( pair&& other ) noexcept(/* see below */); | ||
| + | |since2=c++20|dcl2= | ||
| + | constexpr pair& operator=( pair&& other ) noexcept(/* see below */); | ||
}} | }} | ||
| − | {{dcl | num=4 | | + | {{dcl rev multi|num=4|since1=c++11|dcl1= |
template< class U1, class U2 > | template< class U1, class U2 > | ||
pair& operator=( pair<U1,U2>&& other ); | pair& operator=( pair<U1,U2>&& other ); | ||
| + | |since2=c++20|dcl2= | ||
| + | template< class U1, class U2 > | ||
| + | constexpr pair& operator=( pair<U1,U2>&& other ); | ||
}} | }} | ||
{{dcl end}} | {{dcl end}} | ||
| Line 28: | Line 38: | ||
@4@ Assigns {{c|std::forward<U1>(p.first)}} to {{tt|first}} and {{c|std::forward<U2>(p.second)}} to {{tt|second}}. | @4@ Assigns {{c|std::forward<U1>(p.first)}} to {{tt|first}} and {{c|std::forward<U2>(p.second)}} to {{tt|second}}. | ||
| − | {{ | + | {{rrev multi | until1=c++17 |
| − | + | |rev1= | |
The behavior of these functions is undefined unless: | The behavior of these functions is undefined unless: | ||
* For {{v|1}},{{c|std::is_copy_assignable<first_type>::value}} and {{c|std::is_copy_assignable<second_type>::value}} are both {{c|true}}. | * For {{v|1}},{{c|std::is_copy_assignable<first_type>::value}} and {{c|std::is_copy_assignable<second_type>::value}} are both {{c|true}}. | ||
| Line 35: | Line 45: | ||
* For {{v|3}},{{c|std::is_move_assignable<first_type>::value}} and {{c|std::is_move_assignable<second_type>::value}} are both {{c|true}}. | * For {{v|3}},{{c|std::is_move_assignable<first_type>::value}} and {{c|std::is_move_assignable<second_type>::value}} are both {{c|true}}. | ||
* For {{v|4}},{{c|std::is_assignable<first_type&, U1&&>::value}} and {{c|std::is_assignable<second_type&, U2&&>::value}} are both {{c|true}}. | * For {{v|4}},{{c|std::is_assignable<first_type&, U1&&>::value}} and {{c|std::is_assignable<second_type&, U2&&>::value}} are both {{c|true}}. | ||
| − | + | |rev2= | |
| − | + | ||
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: | 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: | ||
* {{v|1}} is defined as deleted unless {{c|std::is_copy_assignable_v<first_type>}} and {{c|std::is_copy_assignable_v<second_type>}} are both {{c|true}}. | * {{v|1}} is defined as deleted unless {{c|std::is_copy_assignable_v<first_type>}} and {{c|std::is_copy_assignable_v<second_type>}} are both {{c|true}}. | ||
| Line 43: | Line 52: | ||
* {{v|4}} does not participate in overload resolution unless {{c|std::is_assignable_v<first_type&, U1&&>}} and {{c|std::is_assignable_v<second_type&, U2&&>}} are both {{c|true}}. | * {{v|4}} does not participate in overload resolution unless {{c|std::is_assignable_v<first_type&, U1&&>}} and {{c|std::is_assignable_v<second_type&, U2&&>}} are both {{c|true}}. | ||
}} | }} | ||
| − | |||
===Parameters=== | ===Parameters=== | ||
{{par begin}} | {{par begin}} | ||
| Line 72: | Line 80: | ||
{{dsc end}} | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
Revision as of 05:01, 19 November 2018
| (1) | ||
pair& operator=( const pair& other ); |
(until C++20) | |
| constexpr pair& operator=( const pair& other ); |
(since C++20) | |
| (2) | ||
template< class U1, class U2 > pair& operator=( const pair<U1,U2>& other ); |
(until C++20) | |
| template< class U1, class U2 > constexpr pair& operator=( const pair<U1,U2>& other ); |
(since C++20) | |
| (3) | ||
pair& operator=( pair&& other ) noexcept(/* see below */); |
(since C++11) (until C++20) |
|
| constexpr pair& operator=( pair&& other ) noexcept(/* see below */); |
(since C++20) | |
| (4) | ||
template< class U1, class U2 > pair& operator=( pair<U1,U2>&& other ); |
(since C++11) (until C++20) |
|
| template< class U1, class U2 > constexpr pair& operator=( pair<U1,U2>&& other ); |
(since C++20) | |
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 second3) Move assignment operator. Replaces the contents with those of
other using move semantics. |
The behavior of these functions is undefined unless:
|
(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:
|
(since C++17) |
Contents |
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)
Example
| This section is incomplete Reason: no example |
