Extended field attributes for output devices

Extended field attributes apply to 3270 display devices and to printers defined as 3270P or SCS1, that support the 3270 Structured Field and Attribute Processing option.

These attributes also apply to 3270P or SCS1 printers that support the Extended Graphics Character Set (EGCS) if field outlining or DBCS operation is desired. These extended field attributes provide additional field attribute definition beyond that provided in the existing 3270 field attribute. They are associated with a field of characters just as the existing 3270 field attributes are, but they do not take up display positions in the characters buffer. They can define such field characteristics as:

Extended field attributes are defined in the EATTR= keyword of the DFLD statement. They can be dynamically modified by specifying ATTR=nn on the ATTR=YES or ATTR=nn. corresponding MFLD statement.

Any combination of existing and extended field attributes (except protect and validate) can be transmitted in one display output stream.

When dynamic attribute modification (ATTR=YES) is specified for a device field with predefined attributes, an attribute is sent to the device for that field in every output operation, even if the data for this device field is not included in the output message.

These attributes are used:

The default attributes for nonliteral 3270 display device fields are:

The default attributes for literal display device fields are:

The forced attributes for literal display device fields are:

Attribute simulation can be defined for non-3270 display devices but these attributes are applied only when requested by an application program. The device field definition reserves the first byte of the field for attribute data. If the application program then specifies an attribute request, that request is represented in the first byte of the device field.

Field attributes that can be simulated are:
Attribute
Action Taken
High-intensity display
An asterisk (*) is placed in the first byte
Modified field
An underscore character (_) is placed in the first byte
High-intensity and modified field
An exclamation point (!) is placed in the first byte
No display
No data is sent regardless of other attributes, except for DPM

Cursor position for the 3604 can also be specified as a simulated attribute.

If a field is defined to receive simulated attribute data but none is provided by the application program, the first byte is a blank.

For an application program to modify, replace, or simulate attribute data, the message field definition must specify ATTR=YES or ATTR=nn. When attributes are defined this way, the first bytes of the output message field are reserved for attribute data. Any error in the specification causes the DFLD ATTR= or EATTR= specification for that attribute byte to be used, although other attribute or extended attribute specifications are processed.

For DPM devices, fields can be defined to receive attribute data, extended attribute data, or both, from the IMS application program by specifying ATTR=YES or ATTR=nn on the DFLD statement corresponding to the MFLD definition with ATTR=YES or ATTR=nn. The 3270 attributes from the IMS application program can either be converted to simulated attributes and placed in the first byte of the device field or placed unchanged (2 binary bytes as received from the IMS application program) in the first 2 bytes of the device field. The decision to send attributes, extended attributes or simulated attributes is made when the device format is defined. If a field is defined to receive attribute data but none is provided by the IMS application program, the first byte contains a blank if attribute simulation was requested, or the first 2 bytes contain binary zeros if binary attributes were requested.