File Management - IBM

48 File Management V4R5
same call level as the program that contained the TFRCTL command. An
override command in a program that transfers control to another program is not
deleted during the transfer of control.
For an example, see “Effect of TFRCTL on overrides-Scenario” on page 49.
v Several overrides (possibly one per call level, one at the activation group level,
and one at the job level) to a single file are allowed. They are processed
according to the priorities in “Processing priority of overrides” on page 43.
For an example of processing overrides, see “How the system processes
overrides-scenario 1” on page 43.
v You can protect an override from being overridden by overrides at lower call
levels, the activation group level, and the job level; specify SECURE(*YES) on
the override. For an example, see “Securing files against overrides” on page 51.
Effect of exits on overrides: scenario
Exits (ENDPGM, RETURN, or abnormal exits) from a call operation delete
overrides that are scoped to that call level. However, they do not delete overrides
that are issued in that call level that are scoped to the activation group level or the
job level. For example, a RETURN command deletes all overrides scoped to that
call level. Thus, overrides that are scoped to the call level in called programs that
end with a RETURN or ENDPGM command do not apply to the calling program.
This is not true for programs that use the Transfer Control (TFRCTL) command.
In Figure 7, the RETURN command deletes the first override in program B, and
FILE X is opened in program A. However, the RETURN command does not delete
the second override because it is scoped to the job level. FILE B is opened in
program A when program A processes the Open FILE A command.
Program A
.
.
.
CALL PGM(B)
Program B
Override 1 OVRDBF FILE(X) FILE(Y)
Override 2 OVRDBF FILE(A) TOFILE(B) +
OVRSCOPE(*JOB)
.
.
.
RETURN
OPEN FILE X
.
.
.
OPEN FILE A
Figure 7. Example of Effect of Exits on Overrides