- Automatic data
- Data that does not persist across calls. In the absence of a specific
initializer, automatic data get "accidental" values that may
depend on the behavior of the caller or the last function to be called
by the caller.
- External data
- Data with one or more named points by which the data can be referenced
by other program units and data areas. External data is known throughout
an enclave.
- Local data
- Data known only to the routine in which it is declared; equivalent
to local data in C, C++, or Fortran, any
non-EXTERNAL data items in COBOL, and data with the PL/I INTERNAL
attribute (whether implicitly, or by explicit declaration).
Figure 1 shows the simplest
form of the Language Environment program
management model and the resources that each component controls. Refer
to the figure as you read about the program management model.
Figure 1. Program management
model illustration of resource ownership