Join/Await
The Join pattern as implemented in the PPL does not implement any way to notify the main thread when the work is completed. To fix this, I have created a new Join implementation that supports executing a notification handler in the main thread, as with the Async/Await pattern.
As with the TParallel version, this Join accepts multiple TProc parameters. It, however, doesn’t return an ITask interface but IJoin. This interface is similar to the IAsync interface used for the Async/Await pattern. It implements two versions of the Await method. One is the same as in the IAsync version, while the other can be used to catch exceptions raised in tasks:
type
IJoin = interface
['{ED4B4531-B233-4A02-A09A-13EE488FCCA3}']
procedure Await(const awaitProc: TProc); overload;
procedure Await(const awaitProc: TProc<Exception>); overload;
...
