pre_scan_tag and final_scan_tag

[algorithms.parallel_scan.scan_tags]

Types that distinguish the phases of parallel_scan.

Types pre_scan_tag and final_scan_tag are dummy types used in conjunction with parallel_scan. See the example in the parallel_scan section for demonstration of how they are used in the signature of operator().

// Defined in header <oneapi/tbb/parallel_scan.h>

namespace oneapi {
    namespace tbb {

       struct pre_scan_tag {
           static bool is_final_scan();
           operator bool();
       };

       struct final_scan_tag {
           static bool is_final_scan();
           operator bool();
       };

    } // namespace tbb
} // namespace oneapi

Member functions

bool is_final_scan()

true for a final_scan_tag, false, otherwise.

operator bool()

true for a final_scan_tag, false, otherwise.