Current channel example, with LINK commands

Figure 1 illustrates the origin of a program's current channel. It shows five interactive programs. Program A is a top-level program started by, for example, a terminal end user. It isn't started by a program and doesn't have a current channel.

B, C, D, and E are second-, third-, fourth-, and fifth-level programs, respectively.

Program B's current channel is X, passed by the CHANNEL option on the EXEC CICS LINK command issued by program A. Program B modifies channel X by adding one container and deleting another.

Program C's current channel is also X, passed by the CHANNEL option on the EXEC CICS LINK command issued by program B.

Program D has no current channel, because C doesn't pass it one.

Program E's current channel is Y, passed by the CHANNEL option on the EXEC CICS LINK command issued by D.

Table 1 lists the name of the current channel (if any) of each of the five programs shown in Figure 1.