Question

我一直在为此而奋斗。环顾四周，我似乎无法找到答案。我只是创建两个分离的线程，然后在它们两个上使用pthread_exit()，但偶尔会有泄漏。

因为我知道人们会问我：

是的，我已阅读所有其他问题而且没有真正的答案
我将主题标记为detached
我为enough time提供线程初始化和死亡
我已阅读pthread_exit手册并已正确使用
使用-Wall

代码：

int threads_keepalive = 1;

void* thread_do(void *arg){
    while(threads_keepalive)
        sleep(1);
    pthread_exit(NULL);
}

int main(){

    /* Make threads */
    pthread_t* threads;
    threads = malloc(2 * sizeof(pthread_t));
    pthread_create(&threads[0], NULL, thread_do, NULL);
    pthread_create(&threads[1], NULL, thread_do, NULL);
    pthread_detach(threads[0]);
    pthread_detach(threads[1]);
    sleep(1); // MAKING SURE THREADS HAVE INITIALIZED

    /* Kill threads */
    threads_keepalive = 0;
    sleep(5); // MAKING SURE THREADS HAVE UNBLOCKED
    free(threads);

    return 0;
}

运行该代码，虽然它是正确的（至少在我看来），我随机时间会出现内存泄漏。我使用valgrind多次运行相同的测试，如下所示

> gcc test.c -pthread -o test && for i in {1..100}; do valgrind --leak-check=full --track-origins=yes ./test 2>&1 | grep frees; done
==4088==   total heap usage: 8 allocs, 4 frees, 2,230 bytes allocated
==4211==   total heap usage: 8 allocs, 4 frees, 2,230 bytes allocated
==4337==   total heap usage: 8 allocs, 4 frees, 2,230 bytes allocated
==4463==   total heap usage: 8 allocs, 4 frees, 2,230 bytes allocated
==4590==   total heap usage: 8 allocs, 8 frees, 2,230 bytes allocated
==4717==   total heap usage: 8 allocs, 8 frees, 2,230 bytes allocated
==4853==   total heap usage: 8 allocs, 4 frees, 2,230 bytes allocated
==4981==   total heap usage: 8 allocs, 8 frees, 2,230 bytes allocated
==5110==   total heap usage: 8 allocs, 8 frees, 2,230 bytes allocated
==5239==   total heap usage: 8 allocs, 8 frees, 2,230 bytes allocated
..

发生了什么事？

更新：创建一个线程而不是两个线程，不会显示内存泄漏。

Answer 1

您的问题的标题是错误的 - 您没有正确使用线程。但我不认为你的内存泄漏与任何未定义行为的实例有关。它只是一个虚假的＆＃34;泄漏＆＃34;由valgrind报告（假设您正在使用带有glibc的Linux系统）glibc内部。请参阅以下相关问题：

即使使用正确，Pthreads也会泄漏内存

1 个答案: