是否必须加入非分离线程？

Question

我创建了一个可以通过两种不同方法停止的非分离线程。其中一个 (stop()) 通过加入生成的线程来提供同步接口，而另一个 (stopAsync()) 只是将控制变量 m_continue 设置为 false 并且不等待提到要完成的线程。

void run()
{
    while(m_continue)
    {
        // Do something
    }
}

void start()
{
    m_continue = true;
    // Spawn a new thread for run()
}

void stop()
{
    m_continue = false;
    // Join to the spawned thread
}

void stopAsync()
{
    m_continue = false;
}

在调用 stopAsync() 的情况下，run() 方法中的 while 循环结束但没有人加入该线程。这种情况下有资源泄漏吗？是否必须加入非分离线程？

我无法从文档中找出答案。 'Notes' 部分讲述了一些我无法理解的内容。

A thread may either be joinable or detached. If a thread is joinable, then another thread can call pthread_join(3) to wait for the thread to terminate and fetch its exit status. Only when a terminated joinable thread has been joined are the last of its resources released back to the system. When a detached thread terminates, its resources are automatically released back to the system: it is not possible to join with the thread in order to obtain its exit status. Making a thread detached is useful for some types of daemon threads whose exit status the application does not need to care about. By default, a new thread is created in a joinable state, unless attr was set to create the thread in a detached state (using pthread_attr_setdetachstate(3)).

https://linux.die.net/man/3/pthread_create

Answer 1

Only when a terminated joinable thread has been joined are the last of its resources released back to the system.

这部分文档的含义是，如果您不加入线程，则线程退出后仍会分配一些资源。所以这样做类似于在没有 free() 的情况下调用 malloc() - 它不是 "mandatory" 如果你不这样做，它不会立即对你的程序造成问题，但它确实代表资源泄漏，所以如果你在一个长运行程序中重复这样做，你可以耗尽相关资源。

代替加入线程，您的 stopAsync() 可以在设置标志变量之前在另一个线程上调用 pthread_detach()。

请注意，您的 m_continue 变量应该受到同步原语的保护，例如互斥锁或 reader-writer 锁。

是否必须加入非分离线程？

Is it mandatory to join a non-detached thread?

pthreads

pthread-join