std::move
Defined in header <algorithm>
|
||
template
<
class InputIt, class OutputIt >
OutputIt move( InputIt first, InputIt last, |
(1) | (since C++11) (constexpr since C++20) |
template
<
class ExecutionPolicy, class ForwardIt1, class ForwardIt2 >
ForwardIt2 move( ExecutionPolicy&& policy, |
(2) | (since C++17) |
[
first
,
last
)
, to another range beginning at d_first, starting from first and proceeding to last
std::is_execution_policy_v < std::decay_t <ExecutionPolicy>> is true |
(until C++20) |
std::is_execution_policy_v < std::remove_cvref_t <ExecutionPolicy>> is true |
(since C++20) |
If d_first is within the range
[
first
,
last
)
, the behavior is undefined. In this case, std::move_backward
Parameters
first, last | - | the range of elements to move |
d_first | - | the beginning of the destination range |
policy | - | the execution policy to use |
Type requirements | ||
-
InputIt must meet the requirements of LegacyInputIterator
|
||
-
OutputIt must meet the requirements of LegacyOutputIterator
|
||
-
ForwardIt1, ForwardIt2 must meet the requirements of LegacyForwardIterator
|
Return value
The iterator to the element past the last element moved.
Complexity
Exactly std::distance(first, last)
Exceptions
The overload with a template parameter named ExecutionPolicy
reports errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception and
ExecutionPolicy
is one of the standard policies, std::terminate is called. For any otherExecutionPolicy
- If the algorithm fails to allocate memory, std::bad_alloc is thrown.
Possible implementation
template<class InputIt, class OutputIt> OutputIt move(InputIt first, InputIt last, OutputIt d_first) { for (; first != last; ++d_first, ++first) *d_first = std::move(*first); return d_first; } |
Notes
When moving overlapping ranges, std::move
is appropriate when moving to the left (beginning of the destination range is outside the source range) while std::move_backward
Example
The following code moves thread objects (which themselves are not copyable) from one container to another.
#include <algorithm> #include <chrono> #include <iostream> #include <iterator> #include <list> #include <thread> #include <vector> void f(int n) { std::this_thread::sleep_for(std::chrono::seconds(n)); std::cout << "thread " << n << " ended" << std::endl; } int main() { std::vector<std::jthread> v; v.emplace_back(f, 1); v.emplace_back(f, 2); v.emplace_back(f, 3); std::list<std::jthread> l; // copy() would not compile, because std::jthread is noncopyable std::move(v.begin(), v.end(), std::back_inserter(l)); }
Output:
thread 1 ended thread 2 ended thread 3 ended
See also
(C++11)
|
moves a range of elements to a new location in backwards order (function template) |
(C++11)
|
converts the argument to an xvalue (function template) |
(C++20)
|
moves a range of elements to a new location (algorithm function object) |