terminate called after throwing an instance of 'std::system_error' threadpool

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Your m_lockJobsList mutex (and m_notifyJob condvar) gets destroyed before m_workers threads that try to lock it when wake after condvar notification at ThreadPool destructor.

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Itoun
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Itoun

I'm just an Android crazy guy

Updated on December 17, 2021

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  • Itoun
    Itoun over 2 years

    When I run my code :

    nb workers = 12
    I'm i : 0
    HELLO I'm func1
    BYE I'm func2
    terminate called after throwing an instance of 'std::system_error'
      what():  Invalid argument
    Aborted (core dumped)
    

    terminate called after throwing an instance of 'std::system_error'l

    what(): Invalid argument

    #ifndef CPP_PLAZZA_EXAMPLE_H
    #define CPP_PLAZZA_EXAMPLE_H
    
    #include <thread>
    #include <vector>
    #include <list>
    #include <memory>
    #include <functional>
    #include <mutex>
    #include <condition_variable>
    #include <atomic>
    #include <iterator>
    #include <tuple>
    
    class ThreadPool
    {
     public:
      ThreadPool(size_t numThreads);
      virtual ~ThreadPool();
      void executeJob(std::function<void()> job, std::function<void()> notificationJob);
      void wait_for_done();
     private:
      void loop();
      std::pair<std::function<void()>, std::function<void()> > getNextJob();
      std::vector<std::thread> m_workers;
      std::list<std::pair<std::function<void()>, std::function<void()> > > m_jobs;
      std::mutex m_lockJobsList;
      std::condition_variable m_notifyJob;
      std::atomic<bool> m_bTerminate;
      class Terminated: public std::runtime_error
      {
       public:
        Terminated(const std::string& what): std::runtime_error(what) {}
      };
    
    };
    
    #endif //CPP_PLAZZA_EXAMPLE_H
    

    and here it is my .cpp

    #include <iostream>
    #include "example.h"
    
    
    ThreadPool::ThreadPool(size_t numThreads):
     m_workers(numThreads), m_bTerminate(false) {
      m_workers.reserve(numThreads);
      for (size_t i = 0; i < numThreads; i++) {
        this->m_workers.emplace_back(&ThreadPool::loop, this);
      }
      /*for (std::vector<std::thread>::iterator it = this->m_workers.begin(); it != this->m_workers.end(); it++)
        assert(std::next(it, 1) ==);*/
    }
    
    ThreadPool::~ThreadPool() {
        {
            std::unique_lock<std::mutex> lockList(m_lockJobsList);
            m_bTerminate = true;
            m_notifyJob.notify_all();
        }
    
    /*  for(std::vector<std::thread>::iterator it = m_workers.begin(); it != m_workers.end(); it++) {
        it->join();
      }*/
      std::this_thread::sleep_for(std::chrono::seconds(5));
    }
    
    void ThreadPool::executeJob(std::function<void()> job, std::function<void()> notificationJob) {
        std::unique_lock<std::mutex> lockList(m_lockJobsList);
      m_jobs.emplace_back(std::pair<std::function<void()>, std::function<void()> >(std::move(job), std::move(notificationJob)));
      std::cout << m_jobs.size() << std::endl;
        m_notifyJob.notify_one();
    }
    
    std::pair<std::function<void()>, std::function<void()> > ThreadPool::getNextJob() {
        std::unique_lock<std::mutex> lockList(m_lockJobsList);
    
        while(!m_bTerminate)
        {
            if(!m_jobs.empty())
            {
                std::pair<std::function<void()>, std::function<void()>> job = std::ref(m_jobs.front());
                m_jobs.pop_front();
                return job;
            }
    
            m_notifyJob.wait(lockList);
        }
    
        throw Terminated("Thread terminated");
    }
    
    void        func1() {
      std::cout << "HELLO I'm func1" << std::endl;
    
    }
    
    void ThreadPool::loop()
    {
        try
        {
            for(;;)
            {
          std::pair<std::function<void()>, std::function<void()> > job = getNextJob();
          job.first();
          job.second();
            }
        }
        catch(Terminated& e)
        {
        }
    }
    
    
    
    void        func2() {
      std::cout << "BYE I'm func2" << std::endl;
    
    }
    
    void        ThreadPool::wait_for_done()
    {
      std::cout << "nb workers = " << this->m_workers.size() << std::endl;
      int i = 0;
      for(std::vector<std::thread>::iterator it = m_workers.begin(); it != m_workers.end(); ++it) {
        std::cout << "je suis i :  " << i << std::endl;
        i++;
    
        (*it).join();
      }
    }
    
    int     main()
    {
      ThreadPool        pool(6);
    
      pool.executeJob(func1, func2);
      pool.wait_for_done();
    }
    

    I think that my error is I join several time on one thread but how to fix it ?

    Compilation line :

    g++ -Wall -Werror -W -Wextra example.cpp -pthread -std=c++11
    

    I tried joinable before join like this (in wait for done) :

    for(std::vector<std::thread>::iterator it = m_workers.begin(); it != m_workers.end(); ++it) {
        if ((*it).joinable())
            (*it).join();
      }
    

    And I had an infinite loop