What is more efficient (qobject_cast or metaObject()->className())?

[qt_developer]

Hi all,

I have two versions of a code to detect if myWidget is a QCheckBox:

QCheckBox* checkBox = qobject_cast<QCheckBox*>(myWidget);
if (checkBox)
{
	// do something
}

QCheckBox* checkBox = qobject_cast<QCheckBox*>(myWidget);
if (checkBox)
{
	// do something
}

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if ("QCheckBox" == QString(myWidget->metaObject()->className()))
{
	// do something
}

if ("QCheckBox" == QString(myWidget->metaObject()->className()))
{
	// do something
}

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What version is more efficient?

Best regards.