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Definitions of the Terminal Capabilities
This section is divided into many subsections, each for one aspect of
use of display terminals. For writing a display program, you usually
need only check the subsections for the operations you want to use.
For writing a terminal description, you must read each subsection and
fill in the capabilities described there.
String capabilities that are display commands may require numeric
parameters (Note: Parameters.). Most such capabilities do not use
parameters. When a capability requires parameters, this is explicitly
stated at the beginning of its definition. In simple cases, the first
or second sentence of the definition mentions all the parameters, in
the order they should be given, using a name in upper case for each
one. For example, the `rp' capability is a command that requires two
parameters; its definition begins as follows:
String of commands to output a graphic character C, repeated N
In complex cases or when there are many parameters, they are
When a capability is described as obsolete, this means that programs
should not be written to look for it, but terminal descriptions should
still be written to provide it.
When a capability is described as very obsolete, this means that it
should be omitted from terminal descriptions as well.
- Basic characteristics.
- Screen Size
- Screen size, and what happens when it changes.
- Cursor Motion
- Various ways to move the cursor.
- Pushing text up and down on the screen.
- What happens if you write a character in the last column.
- Limiting the part of the window that output affects.
- Erasing one or many lines.
- Insdel Line
- Making new blank lines in mid-screen; deleting lines.
- Insdel Char
- Inserting and deleting characters within a line.
- Highlighting some of the text.
- Underlining some of the text.
- Cursor Visibility
- Making the cursor more or less easy to spot.
- Attracts user's attention; not localized on the screen.
- Recognizing when function keys or arrows are typed.
- Meta Key
- META acts like an extra shift key.
- Commands used to initialize or reset the terminal.
- Pad Specs
- Info for the kernel on how much padding is needed.
- Status Line
- A status line displays "background" information.
- Moving by half-lines, for superscripts and subscripts.
- Controlling auxiliary printers of display terminals.
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