COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

If, at the start of the read operation, the file position indicator is at the end-of-file mark or its
value is not defined, execution of the READ statement is unsuccessful, and the file-status data
item is set to a value other than “00.”
NOTE: After an unsuccessful execution of a READ statement, these values are unpredictable:
◦ The value of the file position indicator
◦ The contents of the current record area
◦ The key of reference
Any key value found in the current record area: that is, the value of the current key for indexed
files or the value of the alternate key for any type of file-system file, because in HP COBOL
sequential and relative files can have alternate keys.
The possible I-O status codes that result from unsuccessful read operations are:
Unsuccessful Read OperationI-O Status Code
The end of file condition arose either in the normal course of events or because the program
tried to read an optional file that was not present.
“10”
A permanent error exists.“30”
The value of the file position indicator is undefined at the beginning of the execution of a
READ statement.
“46”
The file is not open in the INPUT or I-O mode.“47”
A logic error has occurred that is not covered by the “4x” file status codes, and no recovery
is possible.
“90”
The file being read is a file in EDIT format, and some step in the read operation failed due
to non-COBOL causes. The record is not read, and the execution of the READ statement is
unsuccessful.
“91”
• Retrieval
When the file position indicator has a value that permits positioning for the read operation,
the run-time routines use that value to identify the record to be retrieved.
In this topic, if the value of the file position indicator reflects a current key of reference that is
a record key, the comparisons relate to the value of that key for records in the file; otherwise,
the comparisons for a sequential file relate to the record number of the records in the file, and
the comparisons for a relative file relate to the relative record number of the records in the
file.
If the file position indicator was established by a previous OPEN or START statement, then
the record selected for retrieval is one of:
◦ If NEXT is specified or implied, the record whose record number or key value is greater
than or equal to the file position indicator
◦ If REVERSED is specified, the record whose record number or key value is less than or
equal to the file position indicator
410 Procedure Division Verbs