是否有一种方法可以仅知道其ID来加入特定线程？

Question

考虑到有限数量的医生和无限数量的患者（它们是在随机时刻生成的（在while（1）循环中），我需要编写一个描述计划的程序。到目前为止，我已经创建了一个链表）包含当前正在某个医生处接受咨询的线程的ID，并且在命中CTRL + C时while（1）循环中断。此时，不再产生更多的患者，而尚未完成咨询的患者为正在等待完成（使用pthread_join）。现在我的问题是：如何仅从链接列表中知道其ID，如何等待（pthread_join）？对于进程，我有waitpid（pid），但是对于线程，我该如何克服呢？下面是我的代码，如果有帮助

# Define MAX_CONSULTATION_TIME 15
# Define noOfDoctors 4

Struct node
{
    struct node *next;
    pid_t pid;
}*head, *tail;

Void * need_a_doctor(int *noOfPatient)
{

        arrivalTime[*noOfPatient] = time(NULL);
        if(sem_wait(&sem))
    {
        perror(NULL);
        return errno;
    }
    pid_t myPid = pthread_self();
    printf(" pid: %d " , myPid);
    struct node * n;
    n = add_a_new_patient_thread(myPid);    
    int *indexDoctor;
    indexDoctor = (int *)malloc(sizeof(int));
    block_doctor(indexDoctor);
    time_t currentTime = time(NULL);
    unsigned long long periodBlockDoctor = rand() % (MAX_CONSULTATION_TIME + 1);
    printf("Under consultation doctor %d with patient %d\n", (*indexDoctor) + 1, *noOfPatient);
    sleep(periodBlockDoctor);

    release_doctor(indexDoctor);
    printf("Patient %d with doctor %d waited for %ld seconds and the consultation took %lld seconds\n" , (*noOfPatient) , (*indexDoctor) + 1 , currentTime - arrivalTime[*noOfPatient] , periodBlockDoctor);
    remove_an_existing_patient(n);
    if(sem_post(&sem))
    {
        perror(NULL);
        return errno;
    }

    return NULL;
}
int main(int argc, char ** argv)
{
        head = (struct node *)malloc(sizeof(*head));
        tail = (struct node *)malloc(sizeof(*tail));
        srand(time(NULL));
        for(int i = 0 ; i < 4 ; i++)
            doctorTaken[i] = 0;
        if(argc < 1)
        {
            fprintf(stderr , "Invalid number of arguments\n");
            return -1;
        }


        if(pthread_mutex_init(&mtx , NULL))
        {
            perror(NULL);
            return errno;
        }
        if(sem_init(&sem , 0 , noOfDoctors))
        {
            perror(NULL);
            return errno;
        }

        unsigned long long timeWaitingPatient;

        int index;
        signal(SIGINT , handler_function);

        while(1)
        {

        timeWaitingPatient = rand() % 4;
        sleep(timeWaitingPatient);
        if(myExit == 1){ break;}
        printf("Patient no. %d\n" , k);

        int *index;
        index = (int *)malloc(3 * sizeof(int));

        if(index == NULL)
        {
            fprintf(stderr , "Lack of memory");
            return -1;
        }
        (*index) = k;
        pthread_t t;
        if(pthread_create(&t , NULL , need_a_doctor , index))
        {
            perror(NULL);
            return errno;
        }

            k++;
    }
    /*
    How do I join the remaining threads here?
    */
//  }
    return 0;
}

Answer 1

[使用pthread_create创建pthread时，您传入pthread_t*以接收线程ID。然后，您可以通过调用pthread_join并将该线程ID传递给它来等待该线程完成。