File Management - IBM

I/O feedback area for database files
Table 26. I/O Feedback Area for Database Files
Offset Data Type Length Contents
0 Binary 4 Size of the database feedback area, including the
key and the null key field byte map.
4 Character 4
Bits 1-32:
Each bit represents a join logical file in
JFILE keyword.
0 JDFTVAL not supplied for
file
1 JDFTVAL supplied for file
8 Binary 2 Offset from the beginning of the I/O feedback
area for database files to the null key field byte
map which follows the key value (which begins
at offset 34 in this area).
10 Binary 2 Number of locked records.
12 Binary 2 Maximum number of fields.
14 Binary 4 Offset to the field-mapping error-bit map.
18 Character 1 Current file position indication.
Bit 1: Current file position is valid for
get-next-key equal operation.
Bits 2-8: Reserved.
0 File position is not valid.
1 File position is valid.
19 Character 1 Current record deleted indication:
Bits 1-2: Reserved.
Bit 3: Next message indicator.
0 Next message not end of file.
1 Next message may be end of
file.
Bit 4: Deleted record indicator.
0 Current file position is at an
active record.
1 Current file position is at a
deleted record.
Bit 5: Write operation key feedback indicator.
0 Key feedback is not provided
by last write operation.
1 Key feedback is provided by
last write operation.
Appendix A. Feedback area layouts 189