等待QMutex断言

Question

我发现，即使是对QMutex的简单等待也会导致断言。我到底做错什么了？

QMutex mutex;

SyncMgr::SyncMgr(QObject *parent) : QObject(parent)
{
    moveToThread( &thread  );

    thread.start();

    process = new QProcess( this);

    connect( process, SIGNAL(readyReadStandardOutput()), this, SLOT(onReadyReadStandardOutput() ) );
    connect( process, SIGNAL(readyReadStandardError()), this, SLOT(onReadyReadStandardError() ) );
}

SyncMgr::~SyncMgr()
{
    delete process;
}

void SyncMgr::onConnected()
{
    cmdDispatcher.sendGetSerialNo();

    // this asserts
    waitForResponse.wait( &mutex ); // waitForResponse is CWaitCondition object

    // ...
}

我得到断言，错误消息是：

断言: thread\qmutex.cpp中的“复制”，第525行

Answer 1

在调用waitForResponse.wait()之前，您需要锁定互斥锁。SyncMgr::onConnected()方法应该如下所示：

void SyncMgr::onConnected()
{
    cmdDispatcher.sendGetSerialNo();

    mutex.lock();
    waitForResponse.wait( &mutex );
    // do something
    mutex.unlock();

    ...
}

您可以在这里找到更多信息：http://doc.qt.io/qt-5/qwaitcondition.html#wait