Arithmetic Exception Handling

For COBOL, the ADD, COMPUTE, DIVIDE, MULTIPLY, and SUBTRACT statements can have ON SIZE ERROR and NOT ON SIZE ERROR phrases. The phrase ON SIZE ERROR contains an arithmetic exception handler.

Statements in the ON SIZE ERROR phrase are executed when one of the following arithmetic exception conditions take place:

The value of an arithmetic operation result is larger than the resultant-identifier picture size.
Division by zero.
Violation of the rules for the evaluation of exponentiation.

For MULTIPLY arithmetic statements, if any of the individual operations produces a size error condition, the statements in the ON SIZE ERROR phrase is not executed until all of the individual operations are completed.

Control is transferred to the statements defined in the phrase NOT ON SIZE ERROR when a NOT ON SIZE ERROR phrase is specified and no exceptions occurred. In that case, the ON SIZE ERROR is ignored.

Component Maker specialization processes an arithmetic statement with exception handlers in the following way:

If a (NOT) ON SIZE ERROR condition occurred in some interpreting pass, then the arithmetic statement is replaced by the statements in the corresponding phrase.
Those statements will be interpreted at the next pass.