termcap.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)termcap.5	R2.4	7/10/87
.tr ||
.TH termcap 5
.SH Name
termcap \- terminal capability data base
.SH Syntax
/etc/termcap
.SH Description
.NXB "termcap file" "format"
.NXB "terminal" "creating capability data base"
.NXA "termcap file" "printcap file"
.NXA "termcap file" "gettytab file"
The
.PN termcap
file is a data base describing terminals used,
for example, by 
.MS vi 1
and
.MS curses 3x .
Terminals are described in
.PN termcap
by giving a set of capabilities which they have and by describing
how operations are performed.
Padding requirements and initialization sequences
are included in
.PN termcap .
.PP
Entries in
.PN termcap
consist of a number of fields separated by colons (:).
The first entry for each terminal gives
the names which are known for the
terminal, separated by vertical bars (|).
The first name is always 2 characters
long and is used by older Version 6
systems, which store the terminal type
in a 16-bit word in a system-wide data base.
The second name given is the most
common abbreviation for the terminal, and the
last name given should be a long name fully identifying the terminal.
The second name should contain no blanks. 
The last name may contain
blanks for readability.
.SH Capabilities
.nf
(P) indicates padding is commonly needed for these strings.
(P*) indicates that padding may be based on the number of lines affected.

.ta \w'k0-k9  'u +\w'Type  'u +\w'Pad?  'u
\fBName	Type	Pad?	Description\fR
.sp
ae	str	(P)	End alternate character set.
al	str	(P*)	Add new blank line.
am	bool		Terminal has automatic margins.
as	str	(P)	Start alternate character set.
bc	str		Backspace, if not CTRL/H.
bl	str		Audible bell character.
bs	bool		Terminal can backspace with CTRL/H.
bt	str	(P)	Back tab.
bw	bool		Backspace wraps from column 0 to last column.
CC	str		Command character in prototype, if terminal-settable.
ca	bool		Cursor addressable.
cd	str	(P*)	Clear to end of display.
ce	str	(P)	Clear to end of line.
ch	str	(P)	Like \f(CWcm\fP, but horizontal motion only; line stays the same.
cl	str	(P*)	Clear screen.
cm	str	(P)	Cursor motion.
co	num		Number of columns in a line.
cr	str	(P*)	Carriage return (default CTRL/M).
cs	str	(P)	Change scrolling region (VT100); like \f(CWcm\fP.
ct 	str		Clear all tab stops.
cv	str	(P)	Like \f(CWch\fP, but vertical only.
da	bool		Display may be retained above.
dB	num		Number of millisec of \f(CWbs\fP delay needed.
db	bool		Display may be retained below.
dC	num		Number of millisec of \f(CWcr\fP delay needed.
dc	str	(P*)	Delete character.
dF	num		Number of millisec of \f(CWff\fP delay needed.
dl	str	(P*)	Delete line.
dm	str		Delete mode (enter).
dN	num		Number of millisec of \f(CWnl\fP delay needed.
do	str		Move down one line.
ds 	str		Clear host writable status line.
dT	num		Number of millisec of \f(CWta\fP delay needed.
ed	str		End delete mode.
ei	str		End insert mode; give ``:ei=:'' if \f(CWic\fP.
eo	str		Can erase overstrikes with a blank.
es	bool		Standout mode allowed on host writable status line.
ff	str	(P*)	Hard-copy terminal page eject (default CTRL/L).
fs	str		Close host writable status line to writing.
gt	bool		Gtty indicates tabs.
hc	bool		Hard-copy terminal.
hd	str		Half-line down (forward 1/2 linefeed).
ho	str		Home cursor (if no \f(CWcm\fR).
hs	bool		Host writable status line capabilities.
hu	str		Half-line up (reverse 1/2 linefeed).
hz	str		Hazeltine; cannot print tildes (~).
ic	str	(P)	Insert character.
if	str		Name of file containing \f(CWis\fR.
im	str		Insert mode (enter); give ``:im=:'' if \f(CWic\fR.
in	bool		Insert mode distinguishes nulls on display.
ip	str	(P*)	Insert pad after character inserted.
is	str		Terminal initialization string.
k0-k9	str		Sent by \*(lqother\*(rq function keys 0-9.
kb	str		Sent by backspace key.
kd	str		Sent by terminal down arrow key.
ke	str		Out of \*(lqkeypad transmit\*(rq mode.
kh	str		Sent by home key.
kl	str		Sent by terminal left arrow key.
kn	num		Number of \*(lqother\*(rq keys.
ko	str		Termcap entries for other nonfunction keys.
kr	str		Sent by terminal right arrow key.
ks	str		Put terminal in \*(lqkeypad transmit\*(rq mode.
ku	str		Sent by terminal up arrow key.
l0-l9	str		Labels on \*(lqother\*(rq function keys.
le	str		Move cursor left one place.
li	num		Number of lines on screen or page.
ll	str		Last line, first column (if no \f(CWcm\fR).
ma	str		Arrow key map, used by \f(CWvi\fP Version 2 only.
mb	str		Turn on blinking.
md	str		Enter bold (extra-bright) mode.
me	str		Turn off all attributes, normal mode.
mh	str		Enter dim (half-bright) mode.
mi	bool		Safe to move while in insert mode.
ml	str		Memory lock on above cursor.
mr	str		Enter reverse mode.
ms	bool		Safe to move while in standout and underline mode.
mu	str		Memory unlock (turn off memory lock).
nc	bool		No correctly working carriage return (DM2500,H2000).
nd	str		Nondestructive space (cursor right).
nl	str	(P*)	Newline character (default \f(CW\en\fR).
ns	bool		Terminal is a CRT, but does not scroll.
os	bool		Terminal overstrikes.
pc	str		Pad character (rather than null).
pt	bool		Has hardware tabs (may need to be set with \f(CWis\fR).
rc	str		Recover from last save cursor (\f(CWsc\fP).
rf	str		Reset file, like initialization file (\f(CWif\fP) but for reset.
rs	str		Reset string, like initialization string (\f(CWis\fP) but for reset.
sc 	str		Save cursor.
se	str		End stand out mode.
sf	str	(P)	Scroll forwards.
sg	num		Number of blank chars left by \f(CWso\fP or \f(CWse\fP.
so	str		Begin stand out mode.
sr	str	(P)	Scroll reverse (backwards).
st	str		Save cursor.
ta	str	(P)	Tab (other than CTRL/I or with padding).
tc	str		Entry of similar terminal \- must be last.
te	str		String to end programs that use \f(CWcm\fP.
ti	str		String to begin programs that use \f(CWcm\fR.
ts	str		Open host writable status line to writing.[jA.
uc	str		Underscore one char and move past it.
ue	str		End underscore mode.
ug	num		Number of blank chars left by \f(CWus\fP or \f(CWue\fP.
ul	bool		Terminal underlines even though it does not overstrike.
up	str		Upline (cursor up).
us	str		Start underscore mode.
vb	str		Visible bell (may not move cursor).
ve	str		Sequence to end open/visual mode.
vs	str		Sequence to start open/visual mode.
vt	num		Virtual terminal number.
xb	bool		Beehive (f1=escape, f2=CTRL/C).
xn	bool		A newline is ignored after a wrap (Concept).
xr	bool		Return acts like \f(CWce\fP \er \en (Delta Data).
xs	bool		Standout not erased by writing over it (HP 264?).
xt	bool		Tabs are destructive, magic so char (Teleray 1061).
.fi
.PP
.B A Sample Entry
.PP
The following entry, which describes the Concept\-100, is among the more
complex entries in the
.PN termcap
file as of this writing.
This particular `Concept' entry is outdated
and is used as an example only:
.PP
.EX 0
c1\||\|c100\||\|concept100:is=\eEU\eEf\eE7\eE5\eE8\eEl\eENH\eEK\eE\e200\eEo&\e200:\e
	:al=3*\eE^R:am:bs:cd=16*\eE^C:ce=16\eE^S:cl=2*^L:cm=\eEa%+ %+:\e
	:co#80:dc=16\eE^A:dl=3*\eE^B:ei=\eE\e200:eo:im=\eE^P:in:\e
	:ip=16*:li#24:mi:nd=\eE=:se=\eEd\eEe:so=\eED\eEE:ta=8\et:\e
	:ul:up=\eE;:vb=\eEk\eEK:xn:
.EE
.PP
Entries can continue onto multiple lines by giving a backslash (\\) as the last
character of a line. Empty fields
can be included for readability (here between the last field on a line
and the first field on the next).
.PP
.B Types of Capabilities
.PP
Capabilities in
.PN termcap
are of three types:
Boolean capabilities that indicate that the terminal has
some particular feature; numeric capabilities giving
the size of the terminal
or the size of particular delays; and string
capabilities, which give a sequence
that can be used to perform particular
terminal operations.
.PP
All capabilities have 2-letter codes.  For instance, the fact that
the Concept has \*(lqautomatic margins\*(rq 
(that is, an automatic return and linefeed
when the end of a line is reached) is indicated
by the capability \f(CWam\fR.
Hence, the description of the Concept includes \f(CWam\fR.
Numeric capabilities are followed by
the number sign (#) and then the value.
Thus, \f(CWco\fR, which indicates the number of columns the terminal has,
gives the value `80' for the Concept.
.PP
Finally, string-valued capabilities,
such as \f(CWce\fR (clear to end-of-line
sequence), are given by the 2-character code: an equal sign (=)
and then a string ending at the next following colon (:).
A delay in milliseconds may appear after the equal sign (=)
in such a capability. Padding characters are supplied by the
editor after the remainder of the string is sent to provide this delay.
The delay can be either an integer, 
for example, ``20'', or an integer followed by an asterisk (*), 
for example ``3*''.  An asterisk (*)
indicates that the padding required is proportional
to the number of lines affected by the
operation, and the amount given is
the per-affected-unit padding required.
When an asterisk (*) is specified,
it is sometimes useful to give a delay of the form ``3.5'' to 
specify a delay per unit to tenths of milliseconds.
.PP
A number of escape sequences are provided
in the string-valued capabilities
for easy encoding of characters there.  
A \f(CW\eE\fR maps to an ESCAPE
character, \f(CWO^x\fR maps to a
CTRL/x for any appropriate x, and the sequences
\f(CW\en \er \et \eb \ef\fR give a newline,
return, tab, backspace and formfeed.
Finally, characters may be given as three octal digits after a backslash (\\),
and the characters circumflex (^) and backslash (\\) may
be given as \f(CW\e^\fR and \f(CW\e\e\fR.
If it is necessary to place a colon (:) in a
capability, it must be escaped in
octal as \f(CW\e072\fR.
If it is necessary to place a null character in a string capability, it
must be encoded as \f(CW\e200\fR.  The routines that deal with
.PN termcap
use C strings and strip the high bits of the output very late so that
a \f(CW\e200\fR comes out as a \f(CW\e000\fR would.
.br
.ne 5
.PP
.B Preparing Descriptions
.PP
This section outlines how to prepare descriptions of terminals.
The most effective way to prepare a terminal description is by imitating
the description of a similar terminal in
.PN termcap
and to build up a description gradually, using partial descriptions
with
.PN ex
to check that they are correct.
Be aware that a very unusual terminal may expose deficiencies in
the ability of the
.PN termcap
file to describe it
or bugs in
.PN ex .
To easily test a new terminal description,
you can set the environment variable
TERMCAP to a pathname of a file
containing the description you are working
on and the editor will look there rather than in 
.PN /etc/termcap .
TERMCAP can also be set to the termcap entry itself
to avoid reading the file when starting up the editor.
This only works on Version 7 systems.
.PP
.B Basic Capabilities
.PP
The number of columns on each line for the terminal is given by the
\f(CWco\fR numeric capability.  If the terminal is a CRT, the
number of lines on the screen is given by the \f(CWli\fR capability.
If the terminal wraps around to the beginning of the next line when
it reaches the right margin, it
should have the \f(CWam\fR capability.
If the terminal can clear its screen, this is given by the
\f(CWcl\fR string capability.  If the terminal can backspace, it
should have the \f(CWbs\fR capability, unless a backspace is accomplished
by a character other than ^H, in which case you should give
this character as the \f(CWbc\fR string capability.  If it overstrikes,
rather than clearing a position when a character is struck over,
it should have the \f(CWos\fR capability.
.PP
A very important point here is that the local cursor motions encoded
in
.PN termcap
are undefined at the left and top edges of a CRT terminal.
The editor will never attempt to backspace around the left edge, nor
will it attempt to go up locally off the top.  The editor assumes that
feeding off the bottom of the screen will cause the screen to scroll up,
and the \f(CWam\fR capability tells whether the cursor sticks at the right
edge of the screen.
If the terminal has switch-selectable automatic margins,
the
.PN termcap
file usually assumes that this is on, that is, \f(CWam\fR.
.PP
These capabilities suffice to describe
hard-copy and \*(lqglass-tty\*(rq terminals.
Thus, the model 33 teletype is described as:
.EX
t3\||\|33\||\|tty33:co#72:os
.EE
.PP
The Lear Siegler ADM\-3 is described as:
.EX
cl\||\|adm3|3|lsi adm3:am:bs:cl=^Z:li#24:co#80
.EE
.PP
.B Cursor Addressing
.PP
Cursor addressing in the terminal is described by a
\f(CWcm\fR string capability, with 
.MS printf 3s
types of escapes such as \f(CW%x\fR in it.
These substitute to encodings of the current line or column position,
while other characters are passed through unchanged.
If the \f(CWcm\fR string is thought of as being a function, its
arguments are the line and then the column to which motion is desired,
and the \f(CW%\fR encodings have the following meanings:
.PP
.DT
.nf
%d	As in \fIprintf\fR, 0 origin
%2	Like %2d
%3	Like %3d
%.	Like %c
%+x	Adds \fIx\fR to value, then %.
%>xy	If value > x adds y, no output.
%r	Reverses order of line and column, no output
%i	Increments line/column (for 1 origin)
%%	Gives a single %
%n	Exclusive or row and column with 0140 (DM2500)
%B	BCD (16*(x/10)) + (x%10), no output.
%D	Reverse coding (x-2*(x%16)), no output. (Delta Data).
.fi
.PP
Consider the HP2645, which, to get to row 3 and column 12, needs
to be sent \eE&a12c03Y padded for 6 milliseconds.  Note that the order
of the rows and columns is inverted here, and that the row and column
are printed as 2 digits.
Thus, its \f(CWcm\fR capability is ``cm=6\eE&%r%2c%2Y''.