bsl/exchange_8hpp_source.html

 #ifndef BSL_EXCHANGE_HPP
 #define BSL_EXCHANGE_HPP

 #include "forward.hpp"
 #include "move.hpp"

 namespace bsl
 {
     template<typename T, typename U = T>
     constexpr T
     exchange(T &obj, U &&new_value) noexcept(false)
     {
         T const old_value{bsl::move(obj)};
         obj = bsl::forward<U>(new_value);
         return old_value;
     }

 }

 #endif
bsl::exchange
constexpr T exchange(T &obj, U &&new_value) noexcept(false)
Replaces the value of obj with new_value and returns the old value of obj.
Definition: exchange.hpp:54

forward.hpp

move.hpp

bsl::move
constexpr void move(fmt< V > &&val) noexcept=delete
Used to prevent a move of bsl::fmt as it must always be a temporary r-value.