Select in Cilk

Cilk allows for parallel programming, which is similar to the concurrency features in the original example. Here’s how we can implement a similar concept using Cilk:

#include <cilk/cilk.h>
#include <iostream>
#include <chrono>
#include <thread>
#include <string>

std::string one() {
    std::this_thread::sleep_for(std::chrono::seconds(1));
    return "one";
}

std::string two() {
    std::this_thread::sleep_for(std::chrono::seconds(2));
    return "two";
}

int main() {
    std::string result1, result2;

    cilk_spawn [&]() { result1 = one(); }();
    cilk_spawn [&]() { result2 = two(); }();

    cilk_sync;

    std::cout << "received " << result1 << std::endl;
    std::cout << "received " << result2 << std::endl;

    return 0;
}

In this example, we’re using Cilk to create parallel tasks that simulate blocking operations. Here’s a breakdown of the code:

1. We define two functions, one() and two(), which simulate blocking operations by sleeping for 1 and 2 seconds respectively.

2. In the main() function, we use cilk_spawn to create parallel tasks for each function call. These tasks will run concurrently.

3. We use cilk_sync to wait for all spawned tasks to complete before proceeding.

4. After the tasks are complete, we print the results.

To compile and run this program, you would typically use:

$ cilk++ -std=c++11 select.cpp -o select
$ ./select
received one
received two

Note that the total execution time should be just over 2 seconds, as both the 1 and 2 second sleeps execute concurrently.

While Cilk doesn’t have a direct equivalent to Go’s select statement for channel operations, this example demonstrates how to achieve similar concurrent behavior using Cilk’s parallel programming model.