// The program demonstrates how to create asynchronous task

// from an executor and a subflow.

#include <taskflow/taskflow.hpp>

int main() {

tf::Executor executor;

// create asynchronous tasks from the executor

// (using executor as a thread pool)

tf::Future<std::optional<int>> future1 = executor.async([](){

std::cout << "async task 1 returns 1\n";

return 1;

});

executor.silent_async([](){ // silent async task doesn't return

std::cout << "async task 2 does not return (silent)\n";

});

// create asynchronous tasks with names (for profiling)

executor.named_async("async_task", [](){

std::cout << "named async task returns 1\n";

return 1;

});

executor.named_silent_async("silent_async_task", [](){

std::cout << "named silent async task does not return\n";

});

executor.wait_for_all(); // wait for the two async tasks to finish

// create asynchronous tasks from a subflow

// all asynchronous tasks are guaranteed to finish when the subflow joins

tf::Taskflow taskflow;

std::atomic<int> counter {0};

taskflow.emplace([&](tf::Subflow& sf){

for(int i=0; i<100; i++) {

sf.silent_async([&](){ counter.fetch_add(1, std::memory_order_relaxed); });

}

sf.join();

// when subflow joins, all spawned tasks from the subflow will finish

if(counter == 100) {

std::cout << "async tasks spawned from the subflow all finish\n";

}

else {

throw std::runtime_error("this should not happen");

}

});

executor.run(taskflow).wait();

return 0;

}