title: What does the double colon stand for in the Qt documentation?
body: <p>I'm a newbie on Qt, and in the documentation, i don't understand a syntax prototype shown below:</p>
  
  <p>Here is the syntax prototype of the <strong>function</strong> <strong>addTab()</strong> from <strong>QTabWidget class</strong>.</p>
  
  <pre><code>int QTabWidget::addTab(QWidget * page, const QString &amp; label)
  </code></pre>
  
  <p>I don't understand why they are <strong>two colons</strong> after QTabWidget.
  I think it is to said that addTab() comes from QTabWidget class, so if we want to use that function, we have to include QTabWidget (or any class that wrap the whole and include at the same time QTabWidget).
  Is that right ?</p>
  
  <p>But could we write that syntax QTabWidget::addTab(.....) in practical/in a code or it is just a notation for the documentation to signify the class it comes from?</p>