cpp thread joinable between detach and join

#include <assert.h>
#include <atomic>
#include <chrono>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <numeric>
#include <thread>
#include <unistd.h>
#include <uuid/uuid.h>
#include <vector>

void print_num(const int&len)
{ 
    std::cout << "Thread Id:" << std::this_thread::get_id() << ",in " << __FUNCTION__ << std::endl;
    for(int i=0;i<len;i++)
    {
        std::cout<<i+1<<",";
    }
    std::cout<<std::endl;
}

void thread_detach_join(const int&len)
{
    std::cout << "Thread Id:" << std::this_thread::get_id() << ",in " << __FUNCTION__ << std::endl;
    std::thread t1(print_num,len);
    std::cout<<std::boolalpha<<t1.joinable()<<std::endl;
    t1.detach();
    std::this_thread::sleep_for(std::chrono::seconds(1));
    std::cout<<std::boolalpha<<t1.joinable()<<std::endl;
}

void thread_join_joinable(const int&len)
{
    std::cout << "Thread Id:" << std::this_thread::get_id() << ",in " << __FUNCTION__ << std::endl;
    std::thread t1(print_num,std::cref(len));
    std::cout<<std::boolalpha<<t1.joinable()<<std::endl;
    t1.join();
    std::cout<<std::boolalpha<<t1.joinable()<<std::endl;
}

int main(int args, char **argv)
{
    std::cout << "Thread Id:" << std::this_thread::get_id() << ",in " << __FUNCTION__ << std::endl; 
    thread_join_joinable(atoi(argv[1]));
    std::cout<<std::endl;
    thread_detach_join(atoi(argv[1]));
}

 

Compile

g++ -std=c++2a -I. *.cpp -o h1 -luuid

Run

./h1 10;