The ClassFirst function fills a CLASSENTRY structure with information about the first class on the Windows class list. This information includes the name of the class and the instance handle of the task that owns the class.
You use ClassFirst to begin a walk through the Windows class list. The ClassNext function continues the walk by filling a CLASSENTRY structure with information about the next class on the Windows class list.
You use the GetClassInfo function to obtain more specific class information. GetClassInfo requires the instance handle provided by ClassFirst or ClassNext in the CLASSENTRY structure.