Screen Section

The Screen Section provides screen handling facilities for use with ACCEPT and DISPLAY statements. It allows the following:

• The display of non-scrolling forms consisting of areas of the screen as defined in the Screen Section. A Screen Section entry is called a screen description. It is similar in appearance to a data description but defines a screen item or area of the screen rather than an area in memory.
•  The display of data items which constitute non-scrolling forms. The details of the areas of the screen to be used are provided in the associated ACCEPT and DISPLAY operations.

The Screen Section contains a description of each field on the screen which is accessed in a Format 4 ACCEPT or Format 2 DISPLAY operation. Such a field is called a screen item. Many screen items describe only the layout of fields within a field on the screen and are never referenced explicitly.

The Screen Section contains syntax which enables you to:

• Specify the exact location of fields
• Accept data typed at specified positions
• Display literal text at specified positions
• Define screen attributes
• Control console features.

This syntax is defined in the topic Screen Section Entry Skeleton.

Data entry is made to numeric and numeric-edited screen fields in two ways; fixed-format mode and free-format mode. Refer to your COBOL system documentation about user interfaces for further details.

Fixed-format mode is the default manner in which data entry is made to numeric and numeric edited screen fields. This mode formats and echoes the entered data and also moves the cursor in accordance with the requirements of the field's picture specification, as each keystroke is received. Characters other than digits, "+", "-" , and the decimal point character, are rejected; insertion characters in edited fields are skipped over as the cursor moves backwards and forwards; any sign indicator is modified in accordance with its normal specification; floating symbols move left and right in the field, and insertion symbols appear and disappear as digits are inserted or deleted. When the cursor reaches the last character position in a field, any further character entered replaces the last character.

Free-format mode is an alternative manner in which data entry can be made to numeric and numeric-edited screen fields. The default mode is fixed-format mode. Free-format mode allows data to be keyed into a PIC X field of appropriate length, and only when the operator leaves the field is the data reformatted to comply with the picture specification. Once the operator moves the cursor from the field, your COBOL system disregards all characters other than digits and the sign and decimal point symbols. It then extracts, stores, or reformats the numeric value in accordance with the normal COBOL rules for a MOVE to an item with the same picture as the screen item or working storage item. The numeric value is then usually echoed to the screen. See your COBOL system documentation about user interfaces for details on configuration options available to you.

The Screen Section provides screen handling facilities for use with Format 4 ACCEPT and Format 2 DISPLAY statements.