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[/
Copyright 2018 Glen Joseph Fernandes
(glenjofe@gmail.com)
Distributed under the Boost Software License, Version 1.0.
(http://www.boost.org/LICENSE_1_0.txt)
]
[section:exchange exchange]
[simplesect Authors]
* Glen Fernandes
[endsimplesect]
[section Overview]
The header <boost/core/exchange.hpp> provides the function template
`boost::exchange` which is an implementation of the `std::exchange`
function introduced in C++14. `boost::exchange(o, v)` replaces the
value of `o` with `v` and returns the old value of `o`.
[endsect]
[section Examples]
The following example shows `boost::exchange` used to simplify the
implementation of a move constructor.
```
Node(Node&& other)
: head_(boost::exchange(other.head_, nullptr))
, tail_(boost::exchange(other.tail_, nullptr)) { }
```
[endsect]
[section Reference]
```
namespace boost {
template<class T, class U = T>
constexpr T exchange(T& t, U&& u);
}
```
[section Functions]
[*`template<class T, class U = T> constexpr T exchange(T& t, U&& u);`]
Equivalent to:
```
T v = std::move(t);
t = std::forward<U>(u);
return v;
```
[endsect]
[endsect]
[endsect]
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