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std::move

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Revision as of 15:47, 16 July 2012 by 216.239.45.4 (Talk)

 
 
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Template:ddcl list begin <tr class="t-dsc-header">

<td>
Defined in header <algorithm>
</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td >
template< class InputIterator, class OutputIterator >
OutputIterator move( InputIterator first, InputIterator last, OutputIterator d_first );
</td>

<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end

Moves the elements in the range [first, last), to another range beginning at d_first. After this operation the elements in the moved-from range will still contain valid values of the appropriate type, but not necessarily the same values as before the move.

Contents

Parameters

first, last - the range of elements to move
d_first - the beginning of the destination range. If d_first is within [first, last), std::move_backward must be used instead of std::move.

Return value

Output iterator to the element past the last element moved (d_first + (last - first))

Complexity

Exactly last - first move assignments.

Possible implementation

template<class InputIterator, class OutputIterator>
OutputIterator move(InputIterator first, InputIterator last, 
                    OutputIterator d_first)
{
    while (first != last) {
        *d_first++ = std::move(*first++);
    }
    return d_first;
}

Example

The following code moves threads handles (which themselves are not copyable) from one container to another.

#include <iostream>
#include <vector>
#include <list>
#include <iterator>
#include <thread>
#include <chrono>
void f(int n)
{
   std::this_thread::sleep_for(std::chrono::seconds(n));
   std::cout << "thread " << n << " ended" << '\n';
}
int main() {
   std::vector<std::thread> v;
   v.emplace_back(f, 1);
   v.emplace_back(f, 2);
   v.emplace_back(f, 3);
   std::list<std::thread> l;
   // copy() would not compile,because the thread`s parent is noncopyable

      std::move(v.begin(), v.end(), std::back_inserter(l));
   for(auto& t : l) t.join();
}

Output:

thread 1 ended
thread 2 ended
thread 3 ended

See also

Template:cpp/algorithm/dcl list move backward