scope resolution operator

基本解釋

You can access a static property using the scope resolution operator, which consists of a double colon (::).
可以使用範(fàn)圍解析操作符來(lái)訪問(wèn)靜態(tài)屬性，該操作符由雙冒號(hào) (::) 組成。
Notice that both methods refer to the $iodir property using the keywordself and the scope resolution operator.
注意，兩個(gè)方法都使用關(guān)鍵字 self 和訪問(wèn)解析操作符來(lái)引用 $iodir 屬性。
To call a static method from outside of its class, use the class name together with the scope resolution operator and the name of the method.
要從類外部調(diào)用靜態(tài)方法，可使用類名加上範(fàn)圍解析符和方法名。