thread_pool.cc

An example on how to use the ThreadPool class to schedule tasks.

 
#include <iostream>
 
#include <gul14/ThreadPool.h>
#include <gul14/time_util.h>
 
using namespace gul14;
using std::cout;
 
using namespace std::literals;
 
int main()
{
    // Create a pool with 2 threads (returns a shared_ptr<ThreadPool>)
    auto pool = make_thread_pool(2);
 
    pool->add_task([]() { cout << "Task 1\n"; });
    pool->add_task([]() { sleep(1); std::cout << "Task 2\n"; });
 
    // Tasks can be scheduled to start later:
    // This one should start 2 seconds after enqueueing (if a thread is available)
    pool->add_task([]() { cout << "Task 3\n"; }, 2s);
 
    // Probable output:
    // Task 1
    // Task 2
    // Task 3
 
    // Tasks can return results
    auto task = pool->add_task([]() { return 42; });
 
    while (not task.is_complete())
        sleep(0.1);
 
    // get_result() blocks until the task is complete
    cout << "Task result: " << task.get_result() << "\n";
 
    // Tasks can also interact with the pool themselves, e.g. to schedule a continuation:
    pool->add_task(
        [](ThreadPool& pool) {
            cout << "Task 4\n";
            pool.add_task([]() { cout << "Task 5, a second later\n"; }, 1s);
        });
 
    return 0;
}