Function template copy

Function template copy_if

hpx::parallel::v1::copy_if

Synopsis

// In header: <hpx/parallel/detail/copy.hpp>


template<typename ExPolicy, typename InIter, typename OutIter, typename F> 
  unspecified copy_if(ExPolicy && policy, InIter first, InIter last, 
                      OutIter dest, F && f);

Description

Copies the elements in the range, defined by [first, last), to another range beginning at dest. Copies only the elements for which the predicate f returns true. The order of the elements that are not removed is preserved.

	Note
	Complexity: Performs not more than last - first assignments, exactly last - first applications of the predicate f.

The assignments in the parallel copy_if algorithm invoked with an execution policy object of type sequential_execution_policy execute in sequential order in the calling thread.

The assignments in the parallel copy_if algorithm invoked with an execution policy object of type parallel_execution_policy or task_execution_policy are permitted to execute in an unordered fashion in unspecified threads, and indeterminately sequenced within each thread.

Parameters:

`dest`	Refers to the beginning of the destination range.
`f`	Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last).This is an unary predicate which returns true for the required elements. The signature of this predicate should be equivalent to: bool pred(const Type &a); The signature does not need to have const&, but the function must not modify the objects passed to it. The type Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
`first`	Refers to the beginning of the sequence of elements the algorithm will be applied to.
`last`	Refers to the end of the sequence of elements the algorithm will be applied to.
`policy`	The execution policy to use for the scheduling of the iterations.

Template Parameters:

`ExPolicy`	The type of the execution policy to use (deduced). It describes the manner in which the execution of the algorithm may be parallelized and the manner in which it executes the assignments.
`F`	The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of copy_if requires F to meet the requirements of CopyConstructible.
`InIter`	The type of the source iterators used (deduced). This iterator type must meet the requirements of an input iterator.
`OutIter`	The type of the iterator representing the destination range (deduced). This iterator type must meet the requirements of an output iterator.

Returns:

The copy_if algorithm returns a hpx::future<OutIter> if the execution policy is of type task_execution_policy and returns OutIter otherwise. The copy_if algorithm returns the output iterator to the element in the destination range, one past the last element copied.