IBM SC34-6814-04 - Manual (Page 157)

– The data set name
– The file control portion of the log record.
v Checks the data set name to see if it is one of those for which it is known that
batch programs never update existing records, but only insert new records, or do
not make updates at all. The sample program contains a table of such data sets.
If this data set is in the table, UERCBCKO is returned. UERCBCKO means that
CICS is to perform the backout, despite the override option having been used,
because the locked record cannot have been updated by a batch job.
v For all other data sets, it must be assumed that the batch job could have
updated the record being backed out. The sample therefore returns
UERCNORM, which instructs CICS to take the default action of not backing out
the update.
v Exit from the program, making:
– A user trace entry if tracing is active for file control. This has trace point id
X'01E1' and traces:
- An eye-catcher ‘DFH$FCBV EXIT’
- The data set name
- Some text: ‘Update will be backed out’, or ‘Update will not be backed out’
as appropriate.
Related concepts
“The file control recovery program sample exit programs” on page 19
Exit XFCLDEL, file control logical delete exit
XFCLDEL is invoked whenever a WRITE to a VSAM ESDS, or to a BDAM data set,
is being backed out. Because these types of data set do not support deletion, you
can use XFCLDEL to perform a logical delete by amending the record in some way
that flags it as deleted.
When invoked
Invoked when backing out a WRITE to a VSAM ESDS or a BDAM data set.
Exit-specific parameters
UEPBLOGR
Address of the file control portion of the log record representing the
update that is to be backed out by logical deletion. The log record
can be mapped using the DSECT DFHFCLGD.
UEPTRANS
Address of the 4-byte transaction id under which the update that is
being backed out was made.
UEPTRMNL
Address of the 4-byte terminal id for the terminal or principal facility
from which the update that is being backed out was made.
UEPTASK
Address of the 4-byte (packed decimal) task number for the task
under which the update that is being backed out was made.
UEPFDATA
Address of a variable-length field containing the data in the file
control request. The exit program can amend the record data
addressed by this field, marking it in some way that applications
can recognize as representing a logically deleted record.
Chapter 1. Global user exit programs 135