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Difference between revisions of "cpp/utility/tuple/operator="

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< cpp‎ | utility‎ | tuple
(Replaced "replaces" with "assigns" because "replaces" is ambiguous for tuple of references, the standard uses the term "assigns" everywhere for tuple.)
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{{cpp/utility/tuple/navbar}}
 
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tuple& operator=( const tuple& other );
 
tuple& operator=( const tuple& other );
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constexpr tuple& operator=( const tuple& other );
 
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tuple& operator=( tuple&& other ) noexcept(/* see below */);
 
tuple& operator=( tuple&& other ) noexcept(/* see below */);
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constexpr tuple& operator=( tuple&& other ) noexcept(/* see below */);
 
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template< class... UTypes >
 
template< class... UTypes >
 
tuple& operator=( const tuple<UTypes...>& other );
 
tuple& operator=( const tuple<UTypes...>& other );
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|since2=c++20|dcl2=
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template< class... UTypes >
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constexpr tuple& operator=( const tuple<UTypes...>& other );
 
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template< class... UTypes >
 
template< class... UTypes >
 
tuple& operator=( tuple<UTypes...>&& other );
 
tuple& operator=( tuple<UTypes...>&& other );
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|since2=c++20|dcl2=
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template< class... UTypes >
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constexpr tuple& operator=( tuple<UTypes...>&& other );
 
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template< class U1, class U2 >
 
template< class U1, class U2 >
 
tuple& operator=( const pair<U1,U2>& p );
 
tuple& operator=( const pair<U1,U2>& p );
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|since2=c++20|dcl2=
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template< class U1, class U2 >
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constexpr tuple& operator=( const pair<U1,U2>& p );
 
}}
 
}}
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{{dcl rev multi|num=6|since1=c++11|dcl1=
 
template< class U1, class U2 >
 
template< class U1, class U2 >
 
tuple& operator=( pair<U1,U2>&& p );
 
tuple& operator=( pair<U1,U2>&& p );
 +
|since2=c++20|dcl2=
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template< class U1, class U2 >
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constexpr tuple& operator=( pair<U1,U2>&& p );
 
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6) Assigns {{c|std::forward<U1>(p.first)}} to the first element of {{c|*this}} and {{c|std::forward<U2>(p.second)}} to the second element of {{c|*this}}.
 
6) Assigns {{c|std::forward<U1>(p.first)}} to the first element of {{c|*this}} and {{c|std::forward<U2>(p.second)}} to the second element of {{c|*this}}.
  
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The behavior of these functions is undefined unless:
 
The behavior of these functions is undefined unless:
 
* For {{v|1}}, {{c|std::is_copy_assignable<T_i>::value}} is {{c|true}} for all {{tt|T_i}} in {{tt|Types}}.
 
* For {{v|1}}, {{c|std::is_copy_assignable<T_i>::value}} is {{c|true}} for all {{tt|T_i}} in {{tt|Types}}.
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* For {{v|5}}, {{c|1=sizeof...(Types) == 2}} and {{c|std::is_assignable<T_0&, const U1&>::value}} and {{c|std::is_assignable<T_1&, const U2&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
 
* For {{v|5}}, {{c|1=sizeof...(Types) == 2}} and {{c|std::is_assignable<T_0&, const U1&>::value}} and {{c|std::is_assignable<T_1&, const U2&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
 
* For {{v|6}}, {{c|1=sizeof...(Types) == 2}} and {{c|std::is_assignable<T_0&, U1&&>::value}} and {{c|std::is_assignable<T_1&, U2&&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
 
* For {{v|6}}, {{c|1=sizeof...(Types) == 2}} and {{c|std::is_assignable<T_0&, U1&&>::value}} and {{c|std::is_assignable<T_1&, U2&&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
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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 or if there is a size mismatch. 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 or if there is a size mismatch. Specifically:
 
* {{v|1}} is defined as deleted unless {{c|std::is_copy_assignable<T_i>::value}} is {{c|true}} for all {{tt|T_i}} in {{tt|Types}}.
 
* {{v|1}} is defined as deleted unless {{c|std::is_copy_assignable<T_i>::value}} is {{c|true}} for all {{tt|T_i}} in {{tt|Types}}.
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* {{v|6}} does not participate in overload resolution unless {{c|std::is_assignable<T_0&, U1&&>::value}} and {{c|std::is_assignable<T_1&, U2&&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
 
* {{v|6}} does not participate in overload resolution unless {{c|std::is_assignable<T_0&, U1&&>::value}} and {{c|std::is_assignable<T_1&, U2&&>::value}} are both {{c|true}}, where {{tt|T_0}} and {{tt|T_1}} are the two types constituting {{tt|Types}}.
 
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===Parameters===
 
===Parameters===
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Revision as of 05:47, 19 November 2018

 
C++
 
Utilities library
General utilities
Relational operators (deprecated in C++20)
 
std::tuple
 
(1)
tuple& operator=( const tuple& other );
 (since C++11)
(until C++20)
constexpr tuple& operator=( const tuple& other );
 (since C++20)
(2)
tuple& operator=( tuple&& other ) noexcept(/* see below */);
 (since C++11)
(until C++20)
constexpr tuple& operator=( tuple&& other ) noexcept(/* see below */);
 (since C++20)
(3)
template< class... UTypes >
tuple& operator=( const tuple<UTypes...>& other );
 (since C++11)
(until C++20)
template< class... UTypes >
constexpr tuple& operator=( const tuple<UTypes...>& other );
 (since C++20)
(4)
template< class... UTypes >
tuple& operator=( tuple<UTypes...>&& other );
 (since C++11)
(until C++20)
template< class... UTypes >
constexpr tuple& operator=( tuple<UTypes...>&& other );
 (since C++20)
(5)
template< class U1, class U2 >
tuple& operator=( const pair<U1,U2>& p );
 (since C++11)
(until C++20)
template< class U1, class U2 >
constexpr tuple& operator=( const pair<U1,U2>& p );
 (since C++20)
(6)
template< class U1, class U2 >
tuple& operator=( pair<U1,U2>&& p );
 (since C++11)
(until C++20)
template< class U1, class U2 >
constexpr tuple& operator=( pair<U1,U2>&& p );
 (since C++20)

Replaces the contents of the tuple with the contents of another tuple or a pair.

1) Copy assignment operator. Assigns each element of other to the corresponding element of *this.

2) Move assignment operator. For all i, assigns std::forward<Ti>(get<i>(other)) to get<i>(*this).

3) For all i, assigns std::get<i>(other) to std::get<i>(*this).

4) For all i, assigns std::forward<Ui>(std::get<i>(other)) to std::get<i>(*this).

5) Assigns p.first to the first element of *this and p.second to the second element of *this.

6) Assigns std::forward<U1>(p.first) to the first element of *this and std::forward<U2>(p.second) to the second element of *this.

The behavior of these functions is undefined unless:

  • For (1), std::is_copy_assignable<T_i>::value is true for all T_i in Types.
  • For (2), std::is_move_assignable<T_i>::value is true for all T_i in Types.
  • For (3), sizeof...(UTypes) == sizeof...(Types) and std::is_assignable<T_i&, const U_i&>::value is true for all corresponding pairs of types T_i in Types and U_i in UTypes.
  • For (4), sizeof...(UTypes) == sizeof...(Types) and std::is_assignable<T_i&, U_i&&>::value is true for all corresponding pairs of types T_i in Types and U_i in UTypes.
  • For (5), sizeof...(Types) == 2 and std::is_assignable<T_0&, const U1&>::value and std::is_assignable<T_1&, const U2&>::value are both true, where T_0 and T_1 are the two types constituting Types.
  • For (6), sizeof...(Types) == 2 and std::is_assignable<T_0&, U1&&>::value and std::is_assignable<T_1&, U2&&>::value are both true, where T_0 and T_1 are the two types constituting Types.
(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 or if there is a size mismatch. Specifically:

  • (1) is defined as deleted unless std::is_copy_assignable<T_i>::value is true for all T_i in Types.
  • (2) does not participate in overload resolution unless std::is_move_assignable<T_i>::value is true for all T_i in Types.
  • (3) does not participate in overload resolution unless sizeof...(UTypes) == sizeof...(Types) and std::is_assignable<T_i&, const U_i&>::value is true for all corresponding pairs of types T_i in Types and U_i in UTypes.
  • (4) does not participate in overload resolution unless sizeof...(UTypes) == sizeof...(Types) and std::is_assignable<T_i&, U_i&&>::value is true for all corresponding pairs of types T_i in Types and U_i in UTypes.
  • (5) does not participate in overload resolution unless sizeof...(Types) == 2, std::is_assignable<T_0&, const U1&>::value and std::is_assignable<T_1&, const U2&>::value are both true, where T_0 and T_1 are the two types constituting Types.
  • (6) does not participate in overload resolution unless std::is_assignable<T_0&, U1&&>::value and std::is_assignable<T_1&, U2&&>::value are both true, where T_0 and T_1 are the two types constituting Types.
(since C++17)

Contents

Parameters

other - tuple to replace the contents of this tuple
p - pair to replace the contents of this 2-tuple

Return value

*this

Exceptions

1) (none)

2)
noexcept specification:  
noexcept(

    is_nothrow_move_assignable<T0>::value &&
    is_nothrow_move_assignable<T1>::value &&
    is_nothrow_move_assignable<T2>::value &&
    ...

)

3-6) (none)

Example

This section is incomplete
Reason: no example

See also

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