Qt源码分析--QThread(1)

最新推荐文章于 2024-06-29 13:03:54 发布

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最新推荐文章于 2024-06-29 13:03:54 发布 · 833 阅读

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#qt #c++ #开发语言

本文详细剖析了Linux环境下QThread类的源码，重点讲解了QThread的构造、设置父线程、退出与启动方法，以及如何确保线程间的正确同步。特别关注了threadData和QThreadData的作用，以及如何在start函数中设置优先级和线程栈大小。

源码分析在Linux环境。

1.explicit QThread(QObject *parent = nullptr);

QThread::QThread(QObject *parent)
    : QObject(*(new QThreadPrivate), parent)
{
    Q_D(QThread);
    // fprintf(stderr, "QThreadData %p created for thread %p\n", d->data, this);
    d->data->thread = this;
}

QObject::QObject(QObject *parent)
    : d_ptr(new QObjectPrivate)
{
    Q_ASSERT_X(this != parent, Q_FUNC_INFO, "Cannot parent a QObject to itself");
    Q_D(QObject);
    d_ptr->q_ptr = this;
    d->threadData = (parent && !parent->thread()) ? parent->d_func()->threadData : QThreadData::current();
    d->threadData->ref();
    if (parent) {
        QT_TRY {
            if (!check_parent_thread(parent, parent ? parent->d_func()->threadData : 0, d->threadData))
                parent = 0;
            setParent(parent);
        } QT_CATCH(...) {
            d->threadData->deref();
            QT_RETHROW;
        }
    }
#if QT_VERSION < 0x60000
    qt_addObject(this);
#endif
    if (Q_UNLIKELY(qtHookData[QHooks::AddQObject]))
        reinterpret_cast<QHooks::AddQObjectCallback>(qtHookData[QHooks::AddQObject])(this);
    Q_TRACE(QObject_ctor, this);
}

void QObject::setParent(QObject *parent)
{
    Q_D(QObject);
    Q_ASSERT(!d->isWidget);
    d->setParent_helper(parent);
}

void QObjectPrivate::setParent_helper(QObject *o)
{
    Q_Q(QObject);
    Q_ASSERT_X(q != o, Q_FUNC_INFO, "Cannot parent a QObject to itself");
#ifdef QT_DEBUG
    const auto checkForParentChildLoops = qScopeGuard([&](){
        int depth = 0;
        auto p = parent;
        while (p) {
            if (++depth == CheckForParentChildLoopsWarnDepth) {
                qWarning("QObject %p (class: '%s', object name: '%s') may have a loop in its parent-child chain; "
                         "this is undefined behavior",
                         q, q->metaObject()->className(), qPrintable(q->objectName()));
            }
            p = p->parent();