Runtime control

Control of a run unit begins with the program that is called on the system level. Each further program of the run unit is called by means of the CALL statement.
The CALL statement transfers program control to the called program. From there, control is subsequently returned to the calling program by means of the EXIT PROGRAM statement. The program is continued at the statement following the CALL statement.

The following example illustrates the logical structure of a run unit comprising five separately compiled programs, including one nested program:

Example 12-2

Run unit