Method operator()

src/test/checkqueue_tests.cpp:78–83

    UniqueCheck(size_t check_id_in) : check_id(check_id_in){};
    UniqueCheck() : check_id(0){};
    bool operator()()
    {
        LOCK(m);
        results.insert(check_id);
        return true;
    }
    void swap(UniqueCheck& x) { std::swap(x.check_id, check_id); };
};