Processing files with multithreading
In threaded applications, you can code COBOL statements for input and output in QSAM, VSAM, and line-sequential files.
Each
file definition (FD
) has an implicit serialization
lock. This lock is used with automatic serialization logic during
the input or output operation that is associated with the execution
of the following statements:
OPEN
CLOSE
READ
WRITE
REWRITE
START
DELETE
Automatic serialization also occurs for the implicit MOVE
that
is associated with the following statements:
WRITE record-name FROM identifier
READ file-name INTO identifier
Automatic serialization is not applied to any statements specified within the following conditional phrases:
AT END
NOT AT END
INVALID KEY
NOT INVALID KEY
AT END-OF-PAGE
NOT AT END-OF-PAGE