8. URLDownloadToFile function (Windows) | Microsoft Docs
Description: Remarks. URLDownloadToFile binds to a host that supports IBindHost to perform the download. To do this, it first queries the controlling IUnknown passed as pCaller for IServiceProvider, then calls IServiceProvider::QueryService with SID_SBindHost. If pCaller does not support IServiceProvider, IOleObject or IObjectWithSite is used to query the object's host container.