std::tuple<Types...>:: swap
|
Defined in header
<tuple>
|
||
|
void
swap
(
tuple
&
other
)
noexcept
(
/* see below */
)
;
|
(1) |
(since C++11)
(constexpr since C++20) |
|
constexpr
void
swap
(
const
tuple
&
other
)
noexcept
(
/* see below */
)
const
;
|
(2) | (since C++23) |
Calls
swap
(which might be
std::swap
, or might be found via
ADL
) for each element in
*
this
and its corresponding element in
other
.
|
If any selected
|
(until C++23) |
|
If any selected
|
(since C++23) |
Parameters
| other | - | tuple of values to swap |
Return value
(none)
Exceptions
|
noexcept
specification:
noexcept
(
noexcept
(
swap
(
std::
declval
<
T0
&
>>
(
)
,
std::
declval
<
T0
&
>
(
)
)
)
&&
In the expression above, the identifier
|
(until C++17) |
|
1)
noexcept
specification:
noexcept
(
(
std::
is_nothrow_swappable_v
<
Types
>
&&
...
)
)
2)
noexcept
specification:
noexcept
(
(
std::
is_nothrow_swappable_v
<
const
Types
>
&&
...
)
)
|
(since C++17) |
Example
#include <iostream> #include <string> #include <tuple> int main() { std::tuple<int, std::string, float> p1{42, "ABCD", 2.71}, p2; p2 = std::make_tuple(10, "1234", 3.14); auto print_p1_p2 = [&](auto rem) { std::cout << rem << "p1 = {" << std::get<0>(p1) << ", " << std::get<1>(p1) << ", " << std::get<2>(p1) << "}, " << "p2 = {" << std::get<0>(p2) << ", " << std::get<1>(p2) << ", " << std::get<2>(p2) << "}\n"; }; print_p1_p2("Before p1.swap(p2): "); p1.swap(p2); print_p1_p2("After p1.swap(p2): "); swap(p1, p2); print_p1_p2("After swap(p1, p2): "); }
Output:
Before p1.swap(p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14}
After p1.swap(p2): p1 = {10, 1234, 3.14}, p2 = {42, ABCD, 2.71}
After swap(p1, p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14}
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2456 | C++11 |
the
noexcept
specification is ill-formed
|
made to work |
See also
|
(C++11)
|
specializes the
std::swap
algorithm
(function template) |
|
(C++11)
|
swaps the contents
(public member function of
std::pair<T1,T2>
)
|