Indicates that a member is a source of events.
Member of a coclass, property, or method.
For a member of a coclass, this attribute indicates that the member is called rather than implemented.
On a property or method, this attribute indicates that the member returns an object or VARIANT that is a source of events. The object implements the interface IConnectionPointContainer.
IMPLTYPEFLAG_FSOURCE
VARFLAG_SOURCE
FUNCFLAG_SOURCE