IBM OS/390 User Manual
ENTRYPOINT
In VSE, it defines the storage address of the entry point of the subtask. The entry
point must be in storage before the subtask can be successfully attached. The
EP, EPLOC or DE parameter in MVS causes the required module to be loaded
into storage (if it is not already in storage) and begins execution at the entry
specified.
point must be in storage before the subtask can be successfully attached. The
EP, EPLOC or DE parameter in MVS causes the required module to be loaded
into storage (if it is not already in storage) and begins execution at the entry
specified.
The entry-point name must be a member name or an alias in a directory of a
partitioned data set, or it must have been specified in the IDENTIFY macro. If the
specified entry point cannot be located, the new subtask is abnormally
terminated. MVS requires the subtask to perform normal initialization and
termination coding. Therefore, the MVS subtasks are generally separate load
modules rather than interspersed coding that commonly is found in VSE
subtasks.
partitioned data set, or it must have been specified in the IDENTIFY macro. If the
specified entry point cannot be located, the new subtask is abnormally
terminated. MVS requires the subtask to perform normal initialization and
termination coding. Therefore, the MVS subtasks are generally separate load
modules rather than interspersed coding that commonly is found in VSE
subtasks.
SAVE: Defines the address of a formatted user save area for the subtask
containing the general purpose (and floating point) registers while the VSE task
is not active. MVS assumes the responsibility for providing areas to save
registers.
containing the general purpose (and floating point) registers while the VSE task
is not active. MVS assumes the responsibility for providing areas to save
registers.
ECB: Defines a task event control block used in intertask communications and
task synchronization. Both operating systems use a fullword ECB, but individual
bits have different meanings.
task synchronization. Both operating systems use a fullword ECB, but individual
bits have different meanings.
ABSAVE: Used if the subtask is to execute the main task
′
s abnormal termination
STXIT AB routine under VSE. When an ABEND is issued in MVS for a task that
has previously issued an STAE macro, the ABEND is intercepted and control is
given at the STAE exit routine address.
has previously issued an STAE macro, the ABEND is intercepted and control is
given at the STAE exit routine address.
An additional facility available under MVS is the ability to specify an end-of-task
exit routine (ETXR) to be given control after the new task is normally or
abnormally terminated. This is true even if the originating task was active and
must be in virtual storage when required. In a sense, this facility functions
something like an STXIT routine. When a termination interrupt occurs, the routine
is given control. This is a useful facility that you should examine when converting
the ATTACH macro.
exit routine (ETXR) to be given control after the new task is normally or
abnormally terminated. This is true even if the originating task was active and
must be in virtual storage when required. In a sense, this facility functions
something like an STXIT routine. When a termination interrupt occurs, the routine
is given control. This is a useful facility that you should examine when converting
the ATTACH macro.
┌─────┬────────┬───────────────────────┐
│ VSE │ DETACH │ SAVE=savearea
│ VSE │ DETACH │ SAVE=savearea
│
│
│
│
(1)
│
├─────┼────────┼───────────────────────┤
│ MVS │ DETACH │ ─cb loca─ion address
│ MVS │ DETACH │ ─cb loca─ion address
│
│
│
│
(1-12)
│
└─────┴────────┴───────────────────────┘
The VSE DETACH macro, issued by the main task or the subtask itself, causes
the subtask to terminate. An EOJ or CANCEL macro can also perform this
function.
the subtask to terminate. An EOJ or CANCEL macro can also perform this
function.
Under MVS, the DETACH macro is used to remove the task control block of the
subtask from the system and to terminate the subtask and all its subtasks.
DETACH is required when either ECB or ETXR was specified in the ATTACH for
this subtask. Both of these parameters signal to the initiating task that the
subtask has terminated normally or abnormally. The task control blocks for all
subtasks must be removed by the originating task before the originating task can
subtask from the system and to terminate the subtask and all its subtasks.
DETACH is required when either ECB or ETXR was specified in the ATTACH for
this subtask. Both of these parameters signal to the initiating task that the
subtask has terminated normally or abnormally. The task control blocks for all
subtasks must be removed by the originating task before the originating task can
284
VSE to OS/390 Migration Workbook