The scope of a channel

The scope of a channel is the code from which it can be accessed. These examples show the scope of each channel in the diagram.

The scope is important because it defines the lifetime of the channel and container storage. For more information, see Deleting channels and containers and freeing their storage.

The transaction channel DFHTRANSACTION

Channels normally go out of scope when the link level changes. They might therefore not be available to all the programs in a transaction. If you create a channel with the name DFHTRANSACTION, it does not go out of scope when the link level changes. It is thus available to all programs in a transaction, including any exit points that are API enabled. However, the transaction channel cannot be passed to a CICS region at a version earlier than 5.2.

DFHTRANSACTION can be used in all API commands that accept a channel name. However, programs cannot delete the DFHTRANSACTION channel by using the EXEC CICS DELETE CHANNEL command.