Pathway/iTS TCP and Terminal Programming Guide

Programming for Specific Terminals
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
3-6
Using Extended Field Attributes
The SET MINIMUM-ATTR and SET MINIMUM-COLOR statements cause the
information in the working-storage definitions to be extracted and stored in a control
block with other information related to the program unit.
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When a terminal or program unit is started, the TCP initializes the extended field
attribute requirements of the program unit as follows:
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No support for color display attributes is required.
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No support for highlight display attributes is required.
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No support for outline display attributes is required.
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You need not modify existing program units for terminals in the IBM 3270 family
unless you want to use the color, highlight, or outline display attributes.
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When a SET MINIMUM-ATTR or SET MINIMUM-COLOR statement is
executed, the TCP updates the requirements of the program unit for the appropriate
extended field attributes.
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When a DISPLAY BASE statement is executed, the TCP compares the capabilities
of the terminal with the requirements of the program unit:
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If the program unit requires extended field attributes that the terminal does not
support, the TCP aborts the program. Termination status 71 indicates
insufficient support for the color, highlight, or outline display attributes
required.
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If the program unit requires extended field attributes that the terminal does
support, the program unit runs.
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If the TCP determines that a program unit was compiled with color, highlight, or
outline display attributes:
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The TCP uses the default foreground color, green, if you do not specify a
foreground color.
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The TCP issues a READ PARTITION structured field message to the terminal.
The TCP uses the reply to this message to determine the capabilities of the
terminal. If the terminal does not support query reply, the TCP ignores the
extended field attributes. See the IBM 3270 Information System Data Stream
Programmer's Reference Manual for information about building and
transmitting specific reply sequences.
To determine the level of support for these attributes on a given terminal, you can use
the TERMINALINFO statement. This statement determines which extended field
attributes a terminal supports; you can issue the statement at any place in the program.
You usually issue a TERMINALINFO statement before the first DISPLAY BASE
statement in a program unit. You can then determine whether a terminal supports
extended field attributes and take action in the program unit accordingly.
For further information about the TERMINALINFO statement, see the Compaq
NonStop™ Pathway/iTS SCREEN COBOL Reference Manual.