int main()

in example/selective_echo_c++/client.cpp [87:240]
134 lines of code
29 McCabe index (conditional complexity)

int main(int argc, char* argv[]) {
    // Parse gflags. We recommend you to use gflags as well.
    GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);

    // A Channel represents a communication line to a Server. Notice that 
    // Channel is thread-safe and can be shared by all threads in your program.
    brpc::SelectiveChannel channel;
    brpc::ChannelOptions schan_options;
    schan_options.timeout_ms = FLAGS_timeout_ms;
    schan_options.backup_request_ms = FLAGS_backup_ms;
    schan_options.max_retry = FLAGS_max_retry;
    if (channel.Init(FLAGS_load_balancer.c_str(), &schan_options) != 0) {
        LOG(ERROR) << "Fail to init SelectiveChannel";
        return -1;
    }

    // Add sub channels.
    // ================
    std::vector<brpc::ChannelBase*> sub_channels;
    
    // Add an ordinary channel.
    brpc::Channel* sub_channel1 = new brpc::Channel;
    butil::EndPoint pt;
    if (str2endpoint(FLAGS_starting_server.c_str(), &pt) != 0 &&
        hostname2endpoint(FLAGS_starting_server.c_str(), &pt) != 0) {
        LOG(ERROR) << "Invalid address=`" << FLAGS_starting_server << "'";
        return -1;
    }
    brpc::ChannelOptions options;
    options.protocol = FLAGS_protocol;
    options.connection_type = FLAGS_connection_type;
    std::ostringstream os;
    os << "list://";
    for (int i = 0; i < 3; ++i) {
        os << butil::EndPoint(pt.ip, pt.port++) << ",";
    }
    if (sub_channel1->Init(os.str().c_str(), FLAGS_load_balancer.c_str(),
                           &options) != 0) {
        LOG(ERROR) << "Fail to init ordinary channel";
        return -1;
    }
    sub_channels.push_back(sub_channel1);

    // Add a parallel channel.
    brpc::ParallelChannel* sub_channel2 = new brpc::ParallelChannel;
    brpc::ParallelChannelOptions pchan_options;
    pchan_options.fail_limit = 1;
    if (sub_channel2->Init(&pchan_options) != 0) {
        LOG(ERROR) << "Fail to init sub_channel2";
        return -1;
    }
    for (int i = 0; i < 3; ++i) {
        brpc::ChannelOptions options;
        options.protocol = FLAGS_protocol;
        options.connection_type = FLAGS_connection_type;
        brpc::Channel* c = new brpc::Channel;
        if (c->Init(butil::EndPoint(pt.ip, pt.port++), &options) != 0) {
            LOG(ERROR) << "Fail to init sub channel[" << i << "] of pchan";
            return -1;
        }
        if (sub_channel2->AddChannel(c, brpc::OWNS_CHANNEL, NULL, NULL) != 0) {
            LOG(ERROR) << "Fail to add sub channel[" << i << "] into pchan";
            return -1;
        }
    }
    sub_channels.push_back(sub_channel2);

    // Add another selective channel with default options.
    brpc::SelectiveChannel* sub_channel3 = new brpc::SelectiveChannel;
    if (sub_channel3->Init(FLAGS_load_balancer.c_str(), NULL) != 0) {
        LOG(ERROR) << "Fail to init schan";
        return -1;
    }
    for (int i = 0; i < 3; ++i) {
        brpc::Channel* c = new brpc::Channel;
        if (i == 0) {
            os.str("");
            os << "list://";
            for (int j = 0; j < 3; ++j) {
                os << butil::EndPoint(pt.ip, pt.port++) << ",";
            }
            if (c->Init(os.str().c_str(), FLAGS_load_balancer.c_str(),
                        &options) != 0) {
                LOG(ERROR) << "Fail to init sub channel[" << i << "] of schan";
                return -1;
            }
        } else {
            if (c->Init(butil::EndPoint(pt.ip, pt.port++), &options) != 0) {
                LOG(ERROR) << "Fail to init sub channel[" << i << "] of schan";
                return -1;
            }
        }
        if (sub_channel3->AddChannel(c, NULL)) {
            LOG(ERROR) << "Fail to add sub channel[" << i << "] into schan";
            return -1;
        }
    }
    sub_channels.push_back(sub_channel3);

    // Add all sub channels into schan.
    for (size_t i = 0; i < sub_channels.size(); ++i) {
        // note: we don't need the handle for channel removal;
        if (channel.AddChannel(sub_channels[i], NULL/*note*/) != 0) {
            LOG(ERROR) << "Fail to add sub_channel[" << i << "]";
            return -1;
        }
    }
    if (FLAGS_attachment_size > 0) {
        g_attachment.resize(FLAGS_attachment_size, 'a');
    }
    if (FLAGS_request_size <= 0) {
        LOG(ERROR) << "Bad request_size=" << FLAGS_request_size;
        return -1;
    }
    g_request.resize(FLAGS_request_size, 'r');

    std::vector<bthread_t> bids;
    std::vector<pthread_t> pids;
    if (!FLAGS_use_bthread) {
        pids.resize(FLAGS_thread_num);
        for (int i = 0; i < FLAGS_thread_num; ++i) {
            if (pthread_create(&pids[i], NULL, sender, &channel) != 0) {
                LOG(ERROR) << "Fail to create pthread";
                return -1;
            }
        }
    } else {
        bids.resize(FLAGS_thread_num);
        for (int i = 0; i < FLAGS_thread_num; ++i) {
            if (bthread_start_background(
                    &bids[i], NULL, sender, &channel) != 0) {
                LOG(ERROR) << "Fail to create bthread";
                return -1;
            }
        }
    }

    while (!brpc::IsAskedToQuit()) {
        sleep(1);
        LOG(INFO) << "Sending EchoRequest at qps=" << g_latency_recorder.qps(1)
                  << " latency=" << g_latency_recorder.latency(1);
    }

    LOG(INFO) << "EchoClient is going to quit";
    for (int i = 0; i < FLAGS_thread_num; ++i) {
        if (!FLAGS_use_bthread) {
            pthread_join(pids[i], NULL);
        } else {
            bthread_join(bids[i], NULL);
        }
    }

    return 0;
}