HPX - High Performance ParalleX

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Function template wait_some_n

hpx::wait_some_n

Synopsis

// In header: <hpx/lcos/wait_some.hpp>


template<typename InputIter> 
  InputIter wait_some_n(std::size_t n, Iterator first, std::size_t count, 
                        error_code & ec = throws);

Description

The function wait_some_n is an operator allowing to join on the result of all given futures. It AND-composes all future objects given and returns a new future object representing the same list of futures after n of them finished executing.

[Note] Note

The function wait_all returns after n futures have become ready. All input futures are still valid after wait_all returns.

[Note] Note

Calling this version of wait_some_n where count == 0, returns a future with the same elements as the arguments that is immediately ready. Possibly none of the futures in that vector are ready. Each future and shared_future is waited upon and then copied into the collection of the output (returned) future, maintaining the order of the futures in the input collection. The future returned by wait_some_n will not throw an exception, but the futures held in the output collection may.

Parameters:

count

[in] The number of elements in the sequence starting at first.

ec

[in,out] this represents the error status on exit, if this is pre-initialized to hpx::throws the function will throw on error instead.

first

[in] The iterator pointing to the first element of a sequence of future or shared_future objects for which when_all should wait.

n

[in] The number of futures out of the arguments which have to become ready in order for the returned future to get ready.

Returns:

This function returns an Iterator referring to the first element after the last processed input element.


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