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

If a declarative procedure does apply to the file and the time limit expires, the declarative procedure
is performed and program execution continues with the statement following the one terminated.
The value of the file position indicator becomes undefined when an operation exceeds its time
limit. Because you cannot determine where in the operation the time limit was exceeded, you
cannot necessarily try the operation again immediately at the current record.
Overhead
When a file is opened with timed I-O enabled, each I-O statement incurs more overhead than a
file opened without a time limit. Avoid using timed I-O unnecessarily.
When a file is being read with APPROXIMATE positioning, the value used for time limit must take
into account that a READ can take somewhat longer than expected. This can occur when a
nonexistent record is sought, because the operating system searches through the file looking for
the next defined record before reporting the absence of the record sought.
Fatal Error
If a file is opened without the TIME LIMIT phrase, and the TIME LIMIT phrase is specified in a
LOCKFILE, READ, or START statement with a nonnegative value for the time limit, a run-time error
is reported to the process’s home terminal, and the process terminates abnormally with the I-O
status code “90”.
$RECEIVE Timeout
A process that must avoid unnecessary suspension when checking for messages on $RECEIVE can
use timed I-O. If the READ statement specifies the time limit 0 and no message is present, the request
times out immediately.
Arithmetic Operations
Many different statements tell the compiler to perform arithmetic operations, either because they
are arithmetic statements or because they include arithmetic expressions.
The arithmetic statements are:
• ADD (page 284)
• COMPUTE (page 307)
• DIVIDE (page 314)
• MULTIPLY (page 371)
• SUBTRACT (page 466)
Topics:
• Common Features of Arithmetic Statements
• Arithmetic Expressions
• Arithmetic Precision
Common Features of Arithmetic Statements
This section describes the common features of the arithmetic statements, which are:
• Data Conversion and Alignment
• Composite of Operands
• Intermediate Data Items
• Multiple Results
• Incompatible Data
Arithmetic Operations 257