FORTRAN Reference Manual

Utility Routines
FORTRAN Reference Manual—528615-001
15-28
Checkpoint Considerations for Saved Message
Utility Routines
Checkpoint Considerations for Saved Message
Utility Routines
In an HP FORTRAN program the storage space for saved messages is not directly
accessible. When a NonStop process needs to change or delete any saved messages,
a checkpoint list is required. The checkpoint list is a programmer-declared FORTRAN
array where the saved message changes are recorded.
You must transmit the information contained in a checkpoint list to the backup of a
process pair just as you would transmit the value of any critical variable by using the
FORTRAN CHECKPOINT statement. The control list specifier, CPLIST, is recognized
in the CHECKPOINT statement as the optional checkpoint list item.
You can provide any number of CPLIST specifiers in a single CHECKPOINT
statement. The checkpoint list can include other control list items that are legal for the
FORTRAN CHECKPOINT statement; for example:
CHECKPOINT (CPLIST = cplist1, UNIT = 3) item1, item2
FORTRAN interprets CPLIST1 as a checkpoint list and checkpoints the information it
contains as well as the values of item1 and item2. FORTRAN adds checkpoint
information to the list whenever a routine modifies a saved message. After a
checkpoint, the information in CPLIST1 is “emptied”. Its storage space is then available
to record further message changes.
If you want changes to saved messages to be checkpointed, you must furnish a
complete checkpoint list array. The list is an INTEGER*4 array. For information about
how to declare CPLIST, see the CHECKPOINT Statement on page 7-15.
The required number of INTEGER*4 array elements depends on the number of
operations the list must record prior to a checkpoint. This number varies depending on
the routine. The description of the cplist parameter for each SMU routine specifies
the maximum number of elements required for this array.
The first value in the DATA list must be one less than the length of the checkpoint list
array. The second value must be zero. There are 101 elements in the above array. The
first value is 100.
Table 15-5. The Portions of the Startup Message
Portion Name Type Identifies
VOLUME Text Default volume and subvolume names
IN Text Input file name
OUT Text Output file name
STRING Text The startup message’s parameter string (the text
that follows the RUN option list)