Function template for

Function template for_each

hpx::parallel::v1::for_each

Synopsis

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


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

Description

Applies f to the result of dereferencing every iterator in the range [first, last).

	Note
	Complexity: Applies f exactly last - first times.

If f returns a result, the result is ignored.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Unlike its sequential form, the parallel overload of for_each does not return a copy of its Function parameter, since parallelization may not permit efficient state accumulation.

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

The application of function objects in parallel 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:

`f`	Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to: <ignored> pred(const Type &a); The signature does not need to have const&. 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 applies user-provided function objects.
`F`	The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each 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.

Returns:

The for_each algorithm returns a hpx::future<void> if the execution policy is of type task_execution_policy and returns void otherwise.