Visible to Intel only — GUID: GUID-AD4AFF94-CB17-4242-B264-9DBC97BFDBDF
Visible to Intel only — GUID: GUID-AD4AFF94-CB17-4242-B264-9DBC97BFDBDF
parallel_for_each Body semantics and requirements
Description
This page clarifies ParallelForEachBody named requirements for tbb::parallel_for_each algorithm specification.
namespace oneapi { namespace tbb { template <typaname InputIterator, typename Body> void parallel_for_each( InputIterator first, InputIterator last, Body body ); // overload (1) template <typename InputIterator, typename Body> void parallel_for_each( InputIterator first, InputIterator last, Body body, task_group_context& group ); // overload (2) template <typename Container, typename Body> void parallel_for_each( Container& c, Body body ); // overload (3) template <typename Container, typename Body> void parallel_for_each( Container& c, Body body, task_group_context& group ); // overload (4) template <typename Container, typename Body> void parallel_for_each( const Container& c, Body body ); // overload (5) template <typename Container, typename Body> void parallel_for_each( const Container& c, Body body, task_group_context& group ); // overload (6) } // namespace tbb } // namespace oneapi
Terms
iterator determines the type of the iterator passed into parallel_for_each algorithm (which is InputIterator for overloads (1) and (2) and decltype(std::begin(c)) for overloads (3) - (6))
value_type - the type typename std::iterator_traits<iterator>::value_type
reference - the type typename std::iterator_traits<iterator>::reference.
Requirements for different iterator types
If the iterator satisfies Input iterator named requirements from [input.iterators] ISO C++ Standard section and do not satisfies Forward iterator named requirements from [forward.iterators] ISO C++ Standard section, tbb::parallel_for_each requires the execution of the body with an object of type const value_type& or value_type&& to be well-formed. If both forms are well-formed, an overload with rvalue reference will be preferred.
If the iterator satisfies Forward iterator named requirements from [forward.iterators] ISO C++ Standard section, tbb::parallel_for_each requires the execution of the body with an object of type reference to be well-formed.
Requirements for Body with feeder argument
Additional elements submitted into tbb::parallel_for_each through the feeder::add passes to the Body as rvalues and therefore the corresponding execution of the Body is required to be well-formed.