Function check_init

tests/BS_thread_pool_test.cpp:2409–2451

* @brief Check that thread initialization functions and get_index() work. */

 * @brief Check that thread initialization functions and get_index() work.
 */
void check_init()
{
    logln("Comparing thread indices reported by get_index() using an initialization function passed to reset():");
    std::vector<std::atomic<std::size_t>> thread_indices(std::thread::hardware_concurrency());
    std::atomic<bool> correct = true;
    BS::thread_pool pool;
    pool.reset(
        [&thread_indices, &correct](std::size_t idx)
        {
            const std::optional<std::size_t> reported_idx = BS::this_thread::get_index();
            if (reported_idx.has_value())
                thread_indices[idx] = reported_idx.value();
            else
                correct = false;
        });
    pool.wait();
    logln("Checking that all reported indices have values...");
    check(correct);
    correct = true;
    for (std::size_t i = 0; i < thread_indices.size(); ++i)
    {
        if (thread_indices[i] != i)
        {
            correct = false;
            break;
        }
    }
    logln("Checking that all reported indices are correct...");
    check(correct);

    logln("Verifying that the index of the main thread has no value...");
    const std::optional<std::size_t> main_idx = BS::this_thread::get_index();
    check(!main_idx.has_value());

    logln("Verifying that the index of an independent thread has no value...");
    std::thread test_thread(
        []
        {
            const std::optional<std::size_t> ind_idx = BS::this_thread::get_index();
            check(!ind_idx.has_value());
        });
    test_thread.join();
}

/**
 * @brief Check that thread cleanup functions work.