cpp-taskflow/examples/async.cpp at master · feiyunwill/cpp-taskflow · GitHub

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// 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)

std::future<int> fu1 = executor.async("async1", [](){

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

return 1;

});

executor.silent_async("async2", [](){ // silent async task doesn't return any future object

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

});

// create async tasks with runtime

std::future<void> fu2 = executor.async([](tf::Runtime& rt){

printf("async task with a runtime: %p\n", &rt);

});

executor.silent_async([](tf::Runtime& rt){

printf("silent async task with a runtime: %p\n", &rt);

});

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::Runtime& rt){

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

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

}

rt.corun();

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

if(counter == 100) {

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

}

else {

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

}

});

executor.run(taskflow).wait();

return 0;

}

cpp-taskflow/examples/async.cpp at master · feiyunwill/cpp-taskflow · GitHub

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