Assigning arithmetic results (MOVE or COMPUTE)

Move w to z
Compute z = w

In the example above, the two statements in most cases have the same effect. The MOVE statement however carries out the assignment with truncation. You can use the DIAGTRUNC compiler option to request that the compiler issue a warning for MOVE statements that might truncate numeric receivers.

When significant left-order digits would be lost in execution, the COMPUTE statement can detect the condition and allow you to handle it. If you use the ON SIZE ERROR phrase of the COMPUTE statement, the compiler generates code to detect a size-overflow condition. If the condition occurs, the code in the ON SIZE ERROR phrase is performed, and the content of z remains unchanged. If you do not specify the ON SIZE ERROR phrase, the assignment is carried out with truncation. There is no ON SIZE ERROR support for the MOVE statement.

You can also use the COMPUTE statement to assign the result of an arithmetic expression or intrinsic function to a data item. For example:

Compute z = y + (x ** 3)
Compute x = Function Max(x y z)

You can assign the results of date, time, mathematical, and other calculations to data items by using Language Environment® callable services. Language Environment services are available through a standard COBOL CALL statement, and the values they return are passed in the parameters of the CALL statement. For example, you can call the Language Environment service CEESIABS to find the absolute value of a data item by coding the following statement:

Call 'CEESIABS' Using Arg, Feedback-code, Result.

As a result of this call, data item Result is assigned the absolute value of the value in data item Arg; data item Feedback-code contains the return code that indicates whether the service completed successfully. You have to define all the data items in the DATA DIVISION using the correct descriptions according to the requirements of the particular callable service. For the example above, the data items could be defined as follows:

77 Arg            Pic s9(9)  Binary.
77 Feedback-code  Pic x(12)  Display.
77 Result         Pic s9(9)  Binary.