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      std::ranges::move,std::ranges::move_result

      From cppreference.com
      <cpp‎ |algorithm‎ |ranges
       
       
      Algorithm library
      Constrained algorithms and algorithms on ranges(C++20)
      Constrained algorithms, e.g.ranges::copy,ranges::sort, ...
      Execution policies(C++17)
      Sorting and related operations
      Partitioning operations
      Sorting operations
      Binary search operations
      (on partitioned ranges)
      Set operations (on sorted ranges)
      Merge operations (on sorted ranges)
      Heap operations
      Minimum/maximum operations
      (C++11)
      (C++17)
      Lexicographical comparison operations
      Permutation operations
      C library
      Numeric operations
      Operations on uninitialized memory
       
      Constrained algorithms
      All names in this menu belong to namespacestd::ranges
      Non-modifying sequence operations
      Modifying sequence operations
      Partitioning operations
      Sorting operations
      Binary search operations (on sorted ranges)
             
             
      Set operations (on sorted ranges)
      Heap operations
      Minimum/maximum operations
      Permutation operations
      Fold operations
      Operations on uninitialized storage
      Return types
       
      Defined in header<algorithm>
      Call signature
      template<std::input_iterator I,std::sentinel_for<I> S,std::weakly_incrementable O>

      requiresstd::indirectly_movable<I, O>
      constexpr move_result<I, O>

          move( I first, S last, O result);
      (1)(since C++20)
      template<ranges::input_range R,std::weakly_incrementable O>

      requiresstd::indirectly_movable<ranges::iterator_t<R>, O>
      constexpr move_result<ranges::borrowed_iterator_t<R>, O>

          move( R&& r, O result);
      (2)(since C++20)
      Helper types
      template<class I,class O>
      using move_result=ranges::in_out_result<I, O>;
      (3)(since C++20)
      1) Moves the elements in the range, defined by[firstlast), to another range beginning atresult.The behavior is undefined ifresult is within the range[firstlast). In such a case,ranges::move_backward may be used instead.
      2) Same as(1), but usesr as the source range, as if usingranges::begin(r) asfirst, andranges::end(r) aslast.

      The elements in themoved-from range will still contain valid values of the appropriate type, but not necessarily the same values as before the move.

      The function-like entities described on this page arealgorithm function objects (informally known asniebloids), that is:

      Contents

      [edit]Parameters

      first, last - the iterator-sentinel pair defining therange of elements to move
      r - the range of the elements to move
      result - the beginning of the destination range

      [edit]Return value

      {last, result+ N}, where

      1)N=ranges::distance(first, last).
      2)N=ranges::distance(r).

      [edit]Complexity

      ExactlyN move assignments.

      [edit]Notes

      When moving overlapping ranges,ranges::move is appropriate when moving to the left (beginning of the destination range is outside the source range) whileranges::move_backward is appropriate when moving to the right (end of the destination range is outside the source range).

      [edit]Possible implementation

      struct move_fn{template<std::input_iterator I,std::sentinel_for<I> S,std::weakly_incrementable O>    requiresstd::indirectly_movable<I, O>constexpr ranges::move_result<I, O>        operator()(I first, S last, O result)const{for(; first!= last;++first,++result)*result=ranges::iter_move(first);return{std::move(first), std::move(result)};}template<ranges::input_range R,std::weakly_incrementable O>    requiresstd::indirectly_movable<ranges::iterator_t<R>, O>constexpr ranges::move_result<ranges::borrowed_iterator_t<R>, O>        operator()(R&& r, O result)const{return(*this)(ranges::begin(r),ranges::end(r), std::move(result));}}; inlineconstexpr move_fn move{};

      [edit]Example

      The following code moves thread objects (which themselves arenon copyable) from one container to another.

      Run this code
      #include <algorithm>#include <chrono>#include <iostream>#include <iterator>#include <list>#include <thread>#include <vector>usingnamespace std::literals::chrono_literals; void f(std::chrono::milliseconds n){std::this_thread::sleep_for(n);std::cout<<"thread with n="<< n.count()<<"ms ended"<<std::endl;} int main(){std::vector<std::jthread> v;    v.emplace_back(f, 400ms);    v.emplace_back(f, 600ms);    v.emplace_back(f, 800ms); std::list<std::jthread> l; // std::ranges::copy() would not compile, because std::jthread is non-copyable    std::ranges::move(v,std::back_inserter(l));}

      Output:

      thread with n=400ms endedthread with n=600ms endedthread with n=800ms ended

      [edit]See also

      moves a range of elements to a new location in backwards order
      (algorithm function object)[edit]
      copies a range of elements to a new location
      (algorithm function object)[edit]
      copies a range of elements in backwards order
      (algorithm function object)[edit]
      (C++11)
      moves a range of elements to a new location
      (function template)[edit]
      (C++11)
      converts the argument to an xvalue
      (function template)[edit]
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