std::experimental::ranges::exchange

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< cpp‎ | experimental‎ | ranges
 
 
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
 
 
General utilities library
Utility components
exchange
Function objects
Metaprogramming and type traits
Tagged pairs and tuples
                          
tag specifiers
                                      
                          
 
template< MoveConstructible T, class U = T >

    requires Assignable<T&, U>

constexpr T exchange(T& obj, U&& new_val) noexcept(/* see below */);
(ranges TS)

Replaces the value of obj with new_value and returns the old value of obj, as if by

T old_value = std::move(obj);
obj = std::forward<U>(new_value);
return old_value;

Parameters

obj - object whose value to replace
new_value - the value to assign to obj

Return value

The old value of obj

Exceptions

noexcept specification:  
noexcept(std::is_nothrow_move_constructible<T>::value &&
         std::is_nothrow_assignable<T&, U>::value)

Example

See also

(C++14)
replaces the argument with a new value and returns its previous value
(function template)