个人中心
gpt4 book ai didi

c - 通过 pthread_join() 加入两个 pthread 无法按预期工作

转载 作者：塔克拉玛干 更新时间：2023-11-03 01:55:14 28 4
gpt4 key购买 nike

<分区>

我正在创建两个不同的 pthread通过 pthread_create()并通过调用 pthread_join() 等待他们退出.

当我运行程序时，最后的输出是“等待线程 1 完成...”，因此它实际上在尝试加入第一个线程时停止，然后终止。

当我只创建和运行一个线程并等待其执行完成时使用 pthread_join() ，一切正常，输出符合预期。

我在这里错过了什么？我已经在网上搜索并发现 pthread_join()创建多个线程时表现不正常。但是我实际上如何使用它来等待完成两个 pthread 的执行？是吗？

这是我的代码:

typedef struct
{
  double speed_in_kmh;
  double current_power_in_mega_watts;
} DeLorean;

typedef struct
{
  unsigned int* cap_indices;
  unsigned int array_length;
} IndexContainer;

typedef struct {
  unsigned char* c_string;
  unsigned int value;
} FluxCapacitor;

DeLorean* delorean__;
FluxCapacitor** capacitors__;

pthread_mutex_t lock;

// Thread function.
void* assembleDeLorean(void* indices)
{
    // Get mutex to lock function and make sure
    // that only one thread at a time is using it.
    pthread_mutex_lock(&lock);


    // Declare "indices" parameter as IndexContainer.
    IndexContainer* iC = indices;

    double sum = 0;

    // Iterate through all given indices in iC
    // and add value of iC to sum, if index exists.
    for (int i = 0; i < 121; ++i)
    {
        for (int j = 0; j < iC->array_length; ++j)
        {
            if (i == iC->cap_indices[j])
            {
                sum += capacitors__[i]->value;
                break;
            }
        }
    }

    // Assign computed sum to power of global delorean.
    delorean__->current_power_in_mega_watts = sum;

    // Release mutex.
    pthread_mutex_unlock(&lock);

    // Stop thread.
    pthread_exit(NULL);
}

int main(void)
{
    printf("Main thread \"main()\" was started.\n");

    capacitors__ = createFluxCapacitorArray(121);
    delorean__ = createDeLorean(0, 0);

    IndexContainer* iC_1 = malloc(sizeof(*iC_1));
    iC_1->array_length = 21;
    iC_1->cap_indices = malloc(21 * sizeof(unsigned int));

    IndexContainer* iC_2 = malloc(sizeof(*iC_2));
    iC_2->array_length = 100;
    iC_2->cap_indices = malloc(100 * sizeof(unsigned int));

    // Fill iC_1.
    for (int i = 0; i < 21; ++i)
    {
        iC_1->cap_indices[i] = i;
    }

    // Fill iC_2.
    int k = 0;
    for (int i = 21; i < 121; ++i)
    {
        iC_2->cap_indices[k] = i;
        ++k;
    }

    // Declare threads.
    pthread_t thread1, thread2;
    int rT1, rT2;

    // Initialize mutex protecting "assembleDeLorean" function.
    pthread_mutex_init(&lock, NULL);

    // Create & run first thread.
    printf("Creating and running thread1.\n");
    rT1 = pthread_create(&thread1, NULL, assembleDeLorean, &iC_1);
    if (rT1 != 0)
    {
        printf("Thread 1 could not be created.\n");
        return EXIT_FAILURE;
    }

    printf("Return value of creation of thread1: %d\n", rT1);


    // Create & run second thread.
    printf("Creating and running thread2.\n");
    rT2 = pthread_create(&thread2, NULL, assembleDeLorean, &iC_2);
    if (rT2 != 0)
    {
        printf("Thread 2 could not be created.\n");
        return EXIT_FAILURE;
    }

    printf("Return value of creation of thread2: %d\n", rT2);   

    // Wait for threads to finish.
    printf("Waiting for thread1 to finish...\n");
    if (pthread_join(thread1, NULL))
    {
        printf("An error occured while joining thread1.\n");
        return EXIT_FAILURE;
    }

    printf("Thread1 finished!");


    printf("Waiting for thread2 to finish...\n");
    if (pthread_join(thread2, NULL))
    {
        printf("An error occured while joining thread2.\n");
        return EXIT_FAILURE;
    }
    printf("Thread2 finished!");

    return EXIT_SUCCESS;
}

28 4 0
文章推荐： linux - 用于将日志文件复制到单个压缩文件中的 shell 脚本
文章推荐： c++ - 如何在 Win32 C++ 应用程序中将 OpenCV 显示窗口添加为另一个窗口的子窗口？
文章推荐： c++ - 枚举内存范围内的页面
文章推荐： c++ - 如何从 XLL 函数返回数组
塔克拉玛干
个人简介

我是一名优秀的程序员,十分优秀！

滴滴打车优惠券免费领取
滴滴打车优惠券
全站热门文章
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com