Compaq DEC Text Processing Utility AA-PWCBD-TE - Manual (Page 66)

DEC Text Processing Utility Data Types
3.14 Window Data Type
3.14.8 Terminals That Do Not Support Windows
DECTPU supports windows only for ANSI character-cell terminals.
Noncharacter-cell terminals do not support windows and are considered
‘‘unsupported devices.’’
If you are using an unsupported device, you must use the /NODISPLAY qualifier
when you invoke DECTPU. /NODISPLAY informs DECTPU that you do not
expect the device from which you are issuing DECTPU commands to support
screen-oriented editing. If one of the previous conditions exists and you do not
specify the /NODISPLAY qualifier, DECTPU exits with an error condition.
You are using an unsupported device if logical name SYS$INPUT points to an
unsupported device, such as a character-cell terminal.
Appendix B contains more information about DECTPU terminal support.
Chapter 2 contains more information on the /NODISPLAY qualifier.
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