Question

我写了一个小类来同步Linux（实际上是Android）和Windows的线程。

这是我界面的Win32实现：

    class SyncObjectWin32 : public SyncObject
    {
    private:

        const HANDLE m_hEvent;

    public:

        SyncObjectWin32()
          : m_hEvent( ::CreateEvent( NULL, FALSE, FALSE ) )
        {
            if( NULL == m_hEvent )
                throw core::Exception( "sys::SyncObjectWin32::SyncObjectWin32() - Failed to create event." );
        }

        ~SyncObjectWin32()
        {
            ::CloseHandle( m_hEvent );
        }

        void WaitForSignal()
        {
            ::WaitForSingleObject( m_hEvent );
        }

        void Signal()
        {
            ::SetEvent( m_hEvent );
        }
    };

问题在于我不确定POSIX的等价物。到目前为止，我已根据this SO question撰写了以下课程，但由于答案不完整，我不确定如何完成课程：

    class SyncObjectPosix
    {
    private:

        pthread_mutex_t m_oMutex;

    public:

        SyncObjectPosix()
        {
            pthread_mutex_lock( m_oMutex );                 // lock mutex
            bool & signalled = find_signal( condition );  // find predicate
            signalled = true;                          // set predicate
            pthread_mutex_unlock( m_oMutex );               // unlock mutex
            pthread_cond_signal( condition );            // signal condition variable
        }

        ~SyncObjectPosix()
        {

        }

        void WaitForSignal()
        {
            pthread_mutex_lock(mutex);                         // lock mutex
            bool & signalled = find_signal( condition );          // find predicate
            while (!signalled)
            {
              pthread_cond_timedwait(condition, m_oMutex, timeout);
            }
            signalled = false;                                 // reset predicate
            pthread_mutex_unlock( m_oMutex );                       // unlock mutex
        }

        void Signal()
        {

        }
    };

Answer 1

同时检查svn merge -r HEAD:45 yourFile svn ci yourFile -m "Reverting back to rev 45"。如果你只需要一个消费者和一个生产者，它似乎几乎相当于eventfd。

CreateEvent - ＆gt; CreateEvent

eventfd - ＆gt; CloseHandle

close - ＆gt; SetEvent

write - ＆gt; WaitForSingleObject

read - ＆gt; WaitForMultipleObjects和select对应的fd

更多阅读 http://www.sourcexr.com/articles/2013/10/26/lightweight-inter-process-signaling-with-eventfd

Answer 2

所描述的POSIX等价物是POSIX条件变量。请注意，条件变量必须始终与POSIX互斥锁配对使用，但很多情况下，多个条件变量使用相同的互斥锁，因此如果您不打算将互斥锁专用于条件变量，则不应该使用该变量。把它放在课堂上。在Win32和POSIX API之间的意义映射应该是：

function surveyFunction() { var div = document.getElementById("list").value; $.ajax({ type: "POST", url: "possurv.pl", data: div, success: function(result){ $('#survfeedback').html(result); } }); } - ＆gt; CreateEvent

pthread_cond_init - ＆gt; CloseHandle

pthread_cond_destroy - ＆gt; WaitForSingleObject或pthread_cond_wait

pthread_cond_timedwait - ＆gt; SetEvent或pthread_cond_signal

幸运的是，有很多关于此的文档，但我建议使用基本的Programming POSIX Threads。

Answer 3

代码的pthreads相当于：

class SyncObjectPosix
{
private:

    bool signalled;
    pthread_mutex_t mutex;
    pthread_cond_t cond;

public:

    SyncObjectPosix()
    {
        signalled = false;
        pthread_mutex_init(&mutex, NULL);
        pthread_cond_init(&cond, NULL);
    }

    ~SyncObjectPosix()
    {
        pthread_mutex_destroy(&mutex);
        pthread_cond_destroy(&cond);
    }

    void WaitForSignal()
    {
        pthread_mutex_lock(&mutex);
        while (!signalled)
        {
            pthread_cond_wait(&cond, &mutex);
        }
        signalled = false;
        pthread_mutex_unlock(&mutex);
    }

    void Signal()
    {
        pthread_mutex_lock(&mutex);
        signalled = true;
        pthread_mutex_unlock(&mutex);
        pthread_cond_signal(&cond);
    }
};

Answer 4

我们的开源pevents库仅适用于所有平台。这是非常小的（单个文件）C ++代码，您可以将其添加到现有项目中，并访问基于pthreads同步基元构建的Windows事件api。

最重要的花絮是它支持WaitForMultipleObjects。

https://github.com/neosmart/pevents

Linux / POSIX等效于Win32的CreateEvent，SetEvent，WaitForSingleObject

4 个答案: