没有QNetworkConfiguration虽然我可以连接到WIFI

Question

On my Laptop (Qt 5.11, Win10 x64) I am connected via WIFI, Qt https connections work. I wonder why I do not see any active network configurations, but can create HTTP requests. Also m_networkConfigManager->isOnline() is always false . Am I missing something, or is this just a Qt bug?

// signal / slot
connect(m_networkConfigManager, &QNetworkConfigurationManager::updateCompleted, this, &CApplication::onNetworkConfigurationsUpdateCompleted, Qt::QueuedConnection);

// called via signal
void CApplication::onNetworkConfigurationsUpdateCompleted()
{
    const QNetworkConfiguration config = m_networkConfigManager->defaultConfiguration();
    for (const QNetworkConfiguration &config : m_networkConfigManager->allConfigurations())
    {
        // never reached
        const QString cs = CNetworkUtils::toString(config);
        CLogMessage(this).info("Network config: %1") << cs;
    }

    // always false
    bool isOnline = m_networkConfigManager->isOnline();
    .... debug messages, I see onNetworkConfigurationsUpdateCompleted being called 3 times
    ....
}

--- edit ---

• I see onNetworkConfigurationsUpdateCompleted being called 3 times and then somehow periodically every 10 secs.
• after I init m_networkConfigManager I call m_networkConfigManager->updateConfigurations();

--- edit 2 ---

This version yields the same result (false) (not Queued)

connect(m_networkConfigManager, &QNetworkConfigurationManager::updateCompleted, [ = ]
{
   bool isOnline = m_networkConfigManager->isOnline();
   qDebug() << isOnline;
});

and this is never called

connect(m_networkConfigManager, &QNetworkConfigurationManager::onlineStateChanged, [](bool isOnline)
{
    qDebug() << isOnline; // never get here
});

--- edit 3 ---

Follow up question: Disable Qt bearer management at runtime

Answer 1

As of the Qt bug tracking system most likely a Qt bug. The whole bearer system seems to be broken for WIFI, or at least being not very reliable. It is a bit hard to trace since there are different issues in different Qt versions depending on the platform (OS).

• https://bugreports.qt.io/browse/QTBUG-40332
• https://bugreports.qt.io/browse/QTBUG-65586

I am using a simple hack workaround (bad practice, but working). If there is no network configuration this could mean I run into that issue, or there is no network interface at all. In that very case I just set the QAM to Accessible and test via a http request. If it works WIFI is available.

const QList<QNetworkConfiguration> allConfigurations = m_networkConfigManager->allConfigurations();
if (allConfigurations.isEmpty()) {
    m_accessManager->setNetworkAccessible(QNetworkAccessManager::Accessible);`
    .... test Qt http request ....     
}