Boost C++ Libraries

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exchange

Overview
Examples
Reference

Authors

  • Glen Fernandes

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.

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)) { }
namespace boost {
  template<class T, class U = T>
  constexpr T exchange(T& t, U&& u);
}

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;

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