std::experimental::ranges::swap
Defined in header <experimental/ranges/utility>
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namespace { constexpr /* unspecified */ swap = /* unspecified */; |
(ranges TS) (customization point object) |
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Call signature |
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template< class T, class U > requires /* see below */ |
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Exchanges the values referenced by t
and u
.
A call to ranges::swap
is equivalent to:
- template<class T> void swap(T&, T&) = delete;
- template<class T, std::size_t N> void swap(T(&)[N], T(&)[N]) = delete;
- any declarations of
swap
found by argument-dependent lookup.
t
and u
, the program is ill-formed; no diagnostic required.T
and U
are lvalue references to array types of equal extent (but possibly different element types) and ranges::swap(*t, *u) is a valid expression;T
and U
are both V&
for some type V
that meets the syntactic requirements of MoveConstructible<V> and Assignable<V&, V>, exchanges the referenced values as if by V v{std::move(t)}; t = std::move(u); u = std::move(v);. If the semantic requirements of either concept are not satisfied, the program is ill-formed; no diagnostic required.ranges::swap
is ill-formed.ranges::swap can be used in a constant expression if every function it calls (as specified above) can be so used.
Customization point objects
The name ranges::swap
denotes a customization point object, which is a function object of a literal Semiregular
class type (denoted, for exposition purposes, as SwapT
). All instances of SwapT
are equal. Thus, ranges::swap
can be copied freely and its copies can be used interchangeably.
Given a set of types Args...
, if std::declval<Args>()... meet the requirements for arguments to ranges::swap
above, SwapT
will satisfy ranges::Invocable<const SwapT, Args...>. Otherwise, no function call operator of SwapT
participates in overload resolution.
In every translation unit in which ranges::swap
is defined, it refers to the same instance of the customization point object. (This means that it can be used freely in things like inline functions and function templates without violating the one-definition rule.)
Exceptions
swap
is found as described above.std::is_nothrow_move_assignable<V>::value)
Example
This section is incomplete Reason: no example |
See also
swaps the values of two objects (function template) |