Function check_os_process_affinity

tests/BS_thread_pool_test.cpp:2999–3037

* @brief Check that getting and setting OS process affinity works. */

 * @brief Check that getting and setting OS process affinity works.
 */
void check_os_process_affinity()
{
    logln("Checking OS process affinity...");

    log("Obtaining initial process affinity ");
    const std::optional<std::vector<bool>> initial_affinity = BS::get_os_process_affinity();
    check(initial_affinity.has_value());
    logln("Initial affinity is: ", affinity_to_string(initial_affinity));
    const std::size_t num_bits = initial_affinity.has_value() ? initial_affinity->size() : std::thread::hardware_concurrency();

    log("Setting affinity to CPU 1 only ");
    std::vector<bool> cpu_1_in(num_bits, false);
    cpu_1_in[0] = true;
    check(BS::set_os_process_affinity(cpu_1_in));
    log("Obtaining new affinity ");
    const std::optional<std::vector<bool>> cpu_1_out = BS::get_os_process_affinity();
    check(cpu_1_out.has_value());
    check(affinity_to_string(cpu_1_in), affinity_to_string(cpu_1_out));

    log("Setting affinity to alternating CPUs ");
    std::vector<bool> alternating_in(num_bits, false);
    for (std::size_t i = 0; i < num_bits; ++i)
        alternating_in[i] = (i % 2 == 1);
    check(BS::set_os_process_affinity(alternating_in));
    log("Obtaining new affinity ");
    const std::optional<std::vector<bool>> alternating_out = BS::get_os_process_affinity();
    check(alternating_out.has_value());
    check(affinity_to_string(alternating_in), affinity_to_string(alternating_out));

    if (initial_affinity.has_value())
    {
        log("Setting affinity back to initial value ");
        check(BS::set_os_process_affinity(*initial_affinity));
        log("Obtaining new affinity ");
        const std::optional<std::vector<bool>> initial_out = BS::get_os_process_affinity();
        check(initial_out.has_value());
        check(affinity_to_string(initial_affinity), affinity_to_string(initial_out));
    }
}

/**
 * @brief Check that getting and setting OS thread affinity works.