terminfo

title: terminfo(5)

text:
# terminfo(5)

## NAME
terminfo - terminal capability database

## SYNOPSIS
/usr/share/terminfo/*/*

## DESCRIPTION
Terminfo is a database describing terminals, used by screen-oriented programs such as nvi(1), lynx(1), mutt(1), and other curses applications, using high-level calls to libraries such as curses(3X). It is also used via low-level calls by non-curses applications which may be screen-oriented (such as clear(1)) or non-screen (such as tabs(1)).

Terminfo describes terminals by giving a set of capabilities which they have, by specifying how to perform screen operations, and by specifying padding requirements and initialization sequences.

This document describes ncurses version 6.5 (patch 20250705).

### terminfo Entry Syntax
Entries in terminfo consist of a sequence of fields:

- Each field ends with a comma “,” (embedded commas may be escaped with a backslash or written as “\054”).

- White space between fields is ignored.

- The first field in a terminfo entry begins in the first column.

- Newlines and leading whitespace (spaces or tabs) may be used for formatting entries for readability. These are removed from parsed entries.

The infocmp -f and -W options rely on this to format if-then-else expressions, or to enforce maximum line-width. The resulting formatted terminal description can be read by tic.

•

The first field for each terminal gives the names which are known for the terminal, separated by “|” characters.

The first name given is the most common abbreviation for the terminal (its primary name), the last name given should be a long name fully identifying the terminal (see longname(3X)), and all others are treated as synonyms (aliases) for the primary terminal name.

X/Open Curses advises that all names but the last should be in lower case and contain no blanks; the last name may well contain upper case and blanks for readability.

This implementation is not so strict; it allows mixed case in the primary name and aliases. If the last name has no embedded blanks, it allows that to be both an alias and a verbose name (but will warn about this ambiguity).

•

Lines beginning with a “#” in the first column are treated as comments.

While comment lines are valid at any point, the output of captoinfo and infotocap (aliases for tic) will move comments so they occur only between entries.

Terminal names (except for the last, verbose entry) should be chosen using the following conventions. The particular piece of hardware making up the terminal should have a root name, thus “hp2621”. This name should not contain hyphens. Modes that the hardware can be in, or user preferences, should be indicated by appending a hyphen and a mode suffix. Thus, a vt100 in 132-column mode would be vt100-w. The following suffixes should be used where possible:

Suffix

Example

Meaning

-nn

aaa-60

Number of lines on the screen

-np

c100-4p

Number of pages of memory

-am

vt100-am

With automargins (usually the default)

-m

ansi-m

Mono mode; suppress color

-mc

wy30-mc

Magic cookie; spaces when highlighting

-na

c100-na

No arrow keys (leave them in local)

-nam

vt100-nam

Without automatic margins

-nl

hp2621-nl

No status line

-ns

hp2626-ns

No status line

-rv

c100-rv

Reverse video

-s

vt100-s

Enable status line

-vb

wy370-vb

Use visible bell instead of beep

-w

vt100-w

Wide mode (> 80 columns, usually 132)

For more on terminal naming conventions, see the term(7) manual page.

### terminfo Capabilities Syntax
The terminfo entry consists of several capabilities, i.e., features that the terminal has, or methods for exercising the terminal's features.

After the first field (giving the name(s) of the terminal entry), there should be one or more capability fields. These are Boolean, numeric or string names with corresponding values:

- Boolean capabilities are true when present, false when absent. There is no explicit value for Boolean capabilities.

- Numeric capabilities have a “#” following the name, then an unsigned decimal integer value.

- String capabilities have a “=” following the name, then an string of characters making up the capability value.

String capabilities can be split into multiple lines, just as the fields comprising a terminal entry can be split into multiple lines. While blanks between fields are ignored, blanks embedded within a string value are retained, except for leading blanks on a line.

Any capability can be canceled, i.e., suppressed from the terminal entry, by following its name with “@” rather than a capability value.

### Similar Terminals
If there are two very similar terminals, one (the variant) can be defined as being just like the other (the base) with certain exceptions. In the definition of the variant, the string capability use can be given with the name of the base terminal:

- The capabilities given before use override those in the base type named by use.

- If there are multiple use capabilities, they are merged in reverse order. That is, the rightmost use reference is processed first, then the one to its left, and so forth.

- Capabilities given explicitly in the entry override those brought in by use references.

A capability can be canceled by placing xx@ to the left of the use reference that imports it, where xx is the capability. For example, the entry

2621-nl, smkx@, rmkx@, use=2621,

defines a 2621-nl that does not have the smkx or rmkx capabilities, and hence does not turn on the function key labels when in visual mode. This is useful for different modes for a terminal, or for different user preferences.

An entry included via use can contain canceled capabilities, which have the same effect as if those cancels were inline in the using terminal entry.

### Predefined Capabilities
Tables of capabilities ncurses recognizes in a terminfo terminal type description and available to terminfo-using code follow.

- The capability name identifies the symbol by which the programmer using the terminfo API accesses the capability.

- The TI (terminfo) code is the short name used by a person composing or updating a terminal type entry.

Whenever possible, these codes are the same as or similar to those of the ANSI X3.64-1979 standard (now superseded by ECMA-48, which uses identical or very similar names). Semantics are also intended to match those of the specification.

terminfo codes have no hard length limit, but ncurses maintains an informal one of 5 characters to keep them short and to allow the tabs in the source file Caps to line up nicely. (Some standard codes exceed this limit regardless.)

- The TC (termcap) code is that used by the corresponding API of ncurses. (Some capabilities are new, and have names that BSD termcap did not originate.)

- The description field attempts to convey the capability's semantics.

The description field employs a handful of notations.

(P)

indicates that padding may be specified.

(P*)

indicates that padding may vary in proportion to the number of output lines affected.

\#i

indicates the ith parameter of a string capability; the programmer should pass the string to tparm(3X) with the parameters listed.

If the description lists no parameters, passing the string to tparm(3X) may produce unexpected behavior, for instance if the string contains percent signs.

Code

Boolean Capability Name

TI

TC

Description

auto_left_margin

bw

bw

cub1 wraps from column 0 to last column

auto_right_margin

am

am

terminal has automatic margins

no_esc_ctlc

xsb

xb

beehive (f1=escape, f2=ctrl C)

ceol_standout_glitch

xhp

xs

standout not erased by overwriting (hp)

eat_newline_glitch

xenl

xn

newline ignored after 80 cols (concept)

erase_overstrike

eo

eo

can erase overstrikes with a blank

generic_type

gn

gn

generic line type

hard_copy

hc

hc

hardcopy terminal

has_meta_key

km

km

Has a meta key (i.e., sets 8th-bit)

has_status_line

hs

hs

has extra status line

insert_null_glitch

in

in

insert mode distinguishes nulls

memory_above

da

da

display may be retained above the screen

memory_below

db

db

display may be retained below the screen

move_insert_mode

mir

mi

safe to move while in insert mode

move_standout_mode

msgr

ms

safe to move while in standout mode

over_strike

os

os

terminal can overstrike

status_line_esc_ok

eslok

es

escape can be used on the status line

dest_tabs_magic_smso

xt

xt

tabs destructive, magic so char (t1061)

tilde_glitch

hz

hz

cannot print ~'s (Hazeltine)

transparent_underline

ul

ul

underline character overstrikes

xon_xoff

xon

xo

terminal uses xon/xoff handshaking

needs_xon_xoff

nxon

nx

padding will not work, xon/xoff required

prtr_silent

mc5i

5i

printer will not echo on screen

hard_cursor

chts

HC

cursor is hard to see

non_rev_rmcup

nrrmc

NR

smcup does not reverse rmcup

no_pad_char

npc

NP

pad character does not exist

non_dest_scroll_region

ndscr

ND

scrolling region is non-destructive

can_change

ccc

cc

terminal can re-define existing colors

back_color_erase

bce

ut

screen erased with background color

hue_lightness_saturation

hls

hl

terminal uses only HLS color notation (Tektronix)

col_addr_glitch

xhpa

YA

only positive motion for hpa/mhpa caps

cr_cancels_micro_mode

crxm

YB

using cr turns off micro mode

has_print_wheel

daisy

YC

printer needs operator to change character set

row_addr_glitch

xvpa

YD

only positive motion for vpa/mvpa caps

semi_auto_right_margin

sam

YE

printing in last column causes cr

cpi_changes_res

cpix

YF

changing character pitch changes resolution

lpi_changes_res

lpix

YG

changing line pitch changes resolution

Code

Numeric Capability Name

TI

TC

Description

columns

cols

co

number of columns in a line

init_tabs

it

it

tabs initially every # spaces

lines

lines

li

number of lines on screen or page

lines_of_memory

lm

lm

lines of memory if > line. 0 means varies

magic_cookie_glitch

xmc

sg

number of blank characters left by smso or rmso

padding_baud_rate

pb

pb

lowest baud rate where padding needed

virtual_terminal

vt

vt

virtual terminal number (CB/unix)

width_status_line

wsl

ws

number of columns in status line

num_labels

nlab

Nl

number of labels on screen

label_height

lh

lh

rows in each label

label_width

lw

lw

columns in each label

max_attributes

ma

ma

maximum combined attributes terminal can handle

maximum_windows

wnum

MW

maximum number of definable windows

max_colors

colors

Co

maximum number of colors on screen

max_pairs

pairs

pa

maximum number of color-pairs on the screen

no_color_video

ncv

NC

video attributes that cannot be used with colors

The following numeric capabilities are present in the SVr4.0 term structure, but are not yet documented in the man page. They came in with SVr4's printer support.

Code

Numeric Capability Name

TI

TC

Description

buffer_capacity

bufsz

Ya

numbers of bytes buffered before printing

dot_vert_spacing

spinv

Yb

spacing of pins vertically in pins per inch

dot_horz_spacing

spinh

Yc

spacing of dots horizontally in dots per inch

max_micro_address

maddr

Yd

maximum value in micro_..._address

max_micro_jump

mjump

Ye

maximum value in parm_..._micro

micro_col_size

mcs

Yf

character step size when in micro mode

micro_line_size

mls

Yg

line step size when in micro mode

number_of_pins

npins

Yh

numbers of pins in print-head

output_res_char

orc

Yi

horizontal resolution in units per line

output_res_line

orl

Yj

vertical resolution in units per line

output_res_horz_inch

orhi

Yk

horizontal resolution in units per inch

output_res_vert_inch

orvi

Yl

vertical resolution in units per inch

print_rate

cps

Ym

print rate in characters per second

wide_char_size

widcs

Yn

character step size when in double wide mode

buttons

btns

BT

number of buttons on mouse

bit_image_entwining

bitwin

Yo

number of passes for each bit-image row

bit_image_type

bitype

Yp

type of bit-image device

Code

String Capability Name

TI

TC

Description

back_tab

cbt

bt

back tab (P)

bell

bel

bl

audible signal (bell) (P)

carriage_return

cr

cr

carriage return (P*) (P*)

change_scroll_region

csr

cs

change region to line #1 to line #2 (P)

clear_all_tabs

tbc

ct

clear all tab stops (P)

clear_screen

clear

cl

clear screen and home cursor (P*)

clr_eol

el

ce

clear to end of line (P)

clr_eos

ed

cd

clear to end of screen (P*)

column_address

hpa

ch

horizontal position #1, absolute (P)

command_character

cmdch

CC

terminal settable cmd character in prototype !?

cursor_address

cup

cm

move to row #1 columns #2

cursor_down

cud1

do

down one line

cursor_home

home

ho

home cursor (if no cup)

cursor_invisible

civis

vi

make cursor invisible

cursor_left

cub1

le

move left one space

cursor_mem_address

mrcup

CM

memory relative cursor addressing, move to row #1 columns #2

cursor_normal

cnorm

ve

make cursor appear normal (undo civis/cvvis)

cursor_right

cuf1

nd

non-destructive space (move right one space)

cursor_to_ll

ll

ll

last line, first column (if no cup)

cursor_up

cuu1

up

up one line

cursor_visible

cvvis

vs

make cursor very visible

delete_character

dch1

dc

delete character (P*)

delete_line

dl1

dl

delete line (P*)

dis_status_line

dsl

ds

disable status line

down_half_line

hd

hd

half a line down

enter_alt_charset_mode

smacs

as

start alternate character set (P)

enter_blink_mode

blink

mb

turn on blinking

enter_bold_mode

bold

md

turn on bold (extra bright) mode

enter_ca_mode

smcup

ti

string to start programs using cup

enter_delete_mode

smdc

dm

enter delete mode

enter_dim_mode

dim

mh

turn on half-bright mode

enter_insert_mode

smir

im

enter insert mode

enter_secure_mode

invis

mk

turn on blank mode (characters invisible)

enter_protected_mode

prot

mp

turn on protected mode

enter_reverse_mode

rev

mr

turn on reverse video mode

enter_standout_mode

smso

so

begin standout mode

enter_underline_mode

smul

us

begin underline mode

erase_chars

ech

ec

erase #1 characters (P)

exit_alt_charset_mode

rmacs

ae

end alternate character set (P)

exit_attribute_mode

sgr0

me

turn off all attributes

exit_ca_mode

rmcup

te

strings to end programs using cup

exit_delete_mode

rmdc

ed

end delete mode

exit_insert_mode

rmir

ei

exit insert mode

exit_standout_mode

rmso

se

exit standout mode

exit_underline_mode

rmul

ue

exit underline mode

flash_screen

flash

vb

visible bell (may not move cursor)

form_feed

ff

ff

hardcopy terminal page eject (P*)

from_status_line

fsl

fs

return from status line

init_1string

is1

i1

initialization string

init_2string

is2

is

initialization string

init_3string

is3

i3

initialization string

init_file

if

if

name of initialization file

insert_character

ich1

ic

insert character (P)

insert_line

il1

al

insert line (P*)

insert_padding

ip

ip

insert padding after inserted character

key_backspace

kbs

kb

backspace key

key_catab

ktbc

ka

clear-all-tabs key

key_clear

kclr

kC

clear-screen or erase key

key_ctab

kctab

kt

clear-tab key

key_dc

kdch1

kD

delete-character key

key_dl

kdl1

kL

delete-line key

key_down

kcud1

kd

down-arrow key

key_eic

krmir

kM

sent by rmir or smir in insert mode

key_eol

kel

kE

clear-to-end-of-line key

key_eos

ked

kS

clear-to-end-of-screen key

key_f0

kf0

k0

F0 function key

key_f1

kf1

k1

F1 function key

key_f10

kf10

k;

F10 function key

key_f2

kf2

k2

F2 function key

key_f3

kf3

k3

F3 function key

key_f4

kf4

k4

F4 function key

key_f5

kf5

k5

F5 function key

key_f6

kf6

k6

F6 function key

key_f7

kf7

k7

F7 function key

key_f8

kf8

k8

F8 function key

key_f9

kf9

k9

F9 function key

key_home

khome

kh

home key

key_ic

kich1

kI

insert-character key

key_il

kil1

kA

insert-line key

key_left

kcub1

kl

left-arrow key

key_ll

kll

kH

lower-left key (home down)

key_npage

knp

kN

next-page key

key_ppage

kpp

kP

previous-page key

key_right

kcuf1

kr

right-arrow key

key_sf

kind

kF

scroll-forward key

key_sr

kri

kR

scroll-backward key

key_stab

khts

kT

set-tab key

key_up

kcuu1

ku

up-arrow key

keypad_local

rmkx

ke

leave keyboard transmit mode

keypad_xmit

smkx

ks

enter keyboard transmit mode

lab_f0

lf0

l0

label on function key f0 if not f0

lab_f1

lf1

l1

label on function key f1 if not f1

lab_f10

lf10

la

label on function key f10 if not f10

lab_f2

lf2

l2

label on function key f2 if not f2

lab_f3

lf3

l3

label on function key f3 if not f3

lab_f4

lf4

l4

label on function key f4 if not f4

lab_f5

lf5

l5

label on function key f5 if not f5

lab_f6

lf6

l6

label on function key f6 if not f6

lab_f7

lf7

l7

label on function key f7 if not f7

lab_f8

lf8

l8

label on function key f8 if not f8

lab_f9

lf9

l9

label on function key f9 if not f9

meta_off

rmm

mo

turn off meta mode

meta_on

smm

mm

turn on meta mode (8th-bit on)

newline

nel

nw

newline (behave like cr followed by lf)

pad_char

pad

pc

padding char (instead of null)

parm_dch

dch

DC

delete #1 characters (P*)

parm_delete_line

dl

DL

delete #1 lines (P*)

parm_down_cursor

cud

DO

down #1 lines (P*)

parm_ich

ich

IC

insert #1 characters (P*)

parm_index

indn

SF

scroll forward #1 lines (P)

parm_insert_line

il

AL

insert #1 lines (P*)

parm_left_cursor

cub

LE

move #1 characters to the left (P)

parm_right_cursor

cuf

RI

move #1 characters to the right (P*)

parm_rindex

rin

SR

scroll back #1 lines (P)

parm_up_cursor

cuu

UP

up #1 lines (P*)

pkey_key

pfkey

pk

program function key #1 to type string #2

pkey_local

pfloc

pl

program function key #1 to execute string #2

pkey_xmit

pfx

px

program function key #1 to transmit string #2

print_screen

mc0

ps

print contents of screen

prtr_off

mc4

pf

turn off printer

prtr_on

mc5

po

turn on printer

repeat_char

rep

rp

repeat char #1 #2 times (P*)

reset_1string

rs1

r1

reset string

reset_2string

rs2

r2

reset string

reset_3string

rs3

r3

reset string

reset_file

rf

rf

name of reset file

restore_cursor

rc

rc

restore cursor to position of last save_cursor

row_address

vpa

cv

vertical position #1 absolute (P)

save_cursor

sc

sc

save current cursor position (P)

scroll_forward

ind

sf

scroll text up (P)

scroll_reverse

ri

sr

scroll text down (P)

set_attributes

sgr

sa

define video attributes #1-#9 (PG9)

set_tab

hts

st

set a tab in every row, current columns

set_window

wind

wi

current window is lines #1-#2 cols #3-#4

tab

ht

ta

tab to next 8-space hardware tab stop

to_status_line

tsl

ts

move to status line, column #1

underline_char

uc

uc

underline char and move past it

up_half_line

hu

hu

half a line up

init_prog

iprog

iP

path name of program for initialization

key_a1

ka1

K1

upper left of keypad

key_a3

ka3

K3

upper right of keypad

key_b2

kb2

K2

center of keypad

key_c1

kc1

K4

lower left of keypad

key_c3

kc3

K5

lower right of keypad

prtr_non

mc5p

pO

turn on printer for #1 bytes

char_padding

rmp

rP

like ip but when in insert mode

acs_chars

acsc

ac

graphics charset pairs, based on vt100

plab_norm

pln

pn

program label #1 to show string #2

key_btab

kcbt

kB

back-tab key

enter_xon_mode

smxon

SX

turn on xon/xoff handshaking

exit_xon_mode

rmxon

RX

turn off xon/xoff handshaking

enter_am_mode

smam

SA

turn on automatic margins

exit_am_mode

rmam

RA

turn off automatic margins

xon_character

xonc

XN

XON character

xoff_character

xoffc

XF

XOFF character

ena_acs

enacs

eA

enable alternate char set

label_on

smln

LO

turn on soft labels

label_off

rmln

LF

turn off soft labels

key_beg

kbeg

@1

begin key

key_cancel

kcan

@2

cancel key

key_close

kclo

@3

close key

key_command

kcmd

@4

command key

key_copy

kcpy

@5

copy key

key_create

kcrt

@6

create key

key_end

kend

@7

end key

key_enter

kent

@8

enter/send key

key_exit

kext

@9

exit key

key_find

kfnd

@0

find key

key_help

khlp

%1

help key

key_mark

kmrk

%2

mark key

key_message

kmsg

%3

message key

key_move

kmov

%4

move key

key_next

knxt

%5

next key

key_open

kopn

%6

open key

key_options

kopt

%7

options key

key_previous

kprv

%8

previous key

key_print

kprt

%9

print key

key_redo

krdo

%0

redo key

key_reference

kref

&1

reference key

key_refresh

krfr

&2

refresh key

key_replace

krpl

&3

replace key

key_restart

krst

&4

restart key

key_resume

kres

&5

resume key

key_save

ksav

&6

save key

key_suspend

kspd

&7

suspend key

key_undo

kund

&8

undo key

key_sbeg

kBEG

&9

shifted begin key

key_scancel

kCAN

&0

shifted cancel key

key_scommand

kCMD

*1

shifted command key

key_scopy

kCPY

*2

shifted copy key

key_screate

kCRT

*3

shifted create key

key_sdc

kDC

*4

shifted delete-character key

key_sdl

kDL

*5

shifted delete-line key

key_select

kslt

*6

select key

key_send

kEND

*7

shifted end key

key_seol

kEOL

*8

shifted clear-to-end-of-line key

key_sexit

kEXT

*9

shifted exit key

key_sfind

kFND

*0

shifted find key

key_shelp

kHLP

\#1

shifted help key

key_shome

kHOM

\#2

shifted home key

key_sic

kIC

\#3

shifted insert-character key

key_sleft

kLFT

\#4

shifted left-arrow key

key_smessage

kMSG

%a

shifted message key

key_smove

kMOV

%b

shifted move key

key_snext

kNXT

%c

shifted next key

key_soptions

kOPT

%d

shifted options key

key_sprevious

kPRV

%e

shifted previous key

key_sprint

kPRT

%f

shifted print key

key_sredo

kRDO

%g

shifted redo key

key_sreplace

kRPL

%h

shifted replace key

key_sright

kRIT

%i

shifted right-arrow key

key_srsume

kRES

%j

shifted resume key

key_ssave

kSAV

!1

shifted save key

key_ssuspend

kSPD

!2

shifted suspend key

key_sundo

kUND

!3

shifted undo key

req_for_input

rfi

RF

send next input char (for ptys)

key_f11

kf11

F1

F11 function key

key_f12

kf12

F2

F12 function key

key_f13

kf13

F3

F13 function key

key_f14

kf14

F4

F14 function key

key_f15

kf15

F5

F15 function key

key_f16

kf16

F6

F16 function key

key_f17

kf17

F7

F17 function key

key_f18

kf18

F8

F18 function key

key_f19

kf19

F9

F19 function key

key_f20

kf20

FA

F20 function key

key_f21

kf21

FB

F21 function key

key_f22

kf22

FC

F22 function key

key_f23

kf23

FD

F23 function key

key_f24

kf24

FE

F24 function key

key_f25

kf25

FF

F25 function key

key_f26

kf26

FG

F26 function key

key_f27

kf27

FH

F27 function key

key_f28

kf28

FI

F28 function key

key_f29

kf29

FJ

F29 function key

key_f30

kf30

FK

F30 function key

key_f31

kf31

FL

F31 function key

key_f32

kf32

FM

F32 function key

key_f33

kf33

FN

F33 function key

key_f34

kf34

FO

F34 function key

key_f35

kf35

FP

F35 function key

key_f36

kf36

FQ

F36 function key

key_f37

kf37

FR

F37 function key

key_f38

kf38

FS

F38 function key

key_f39

kf39

FT

F39 function key

key_f40

kf40

FU

F40 function key

key_f41

kf41

FV

F41 function key

key_f42

kf42

FW

F42 function key

key_f43

kf43

FX

F43 function key

key_f44

kf44

FY

F44 function key

key_f45

kf45

FZ

F45 function key

key_f46

kf46

Fa

F46 function key

key_f47

kf47

Fb

F47 function key

key_f48

kf48

Fc

F48 function key

key_f49

kf49

Fd

F49 function key

key_f50

kf50

Fe

F50 function key

key_f51

kf51

Ff

F51 function key

key_f52

kf52

Fg

F52 function key

key_f53

kf53

Fh

F53 function key

key_f54

kf54

Fi

F54 function key

key_f55

kf55

Fj

F55 function key

key_f56

kf56

Fk

F56 function key

key_f57

kf57

Fl

F57 function key

key_f58

kf58

Fm

F58 function key

key_f59

kf59

Fn

F59 function key

key_f60

kf60

Fo

F60 function key

key_f61

kf61

Fp

F61 function key

key_f62

kf62

Fq

F62 function key

key_f63

kf63

Fr

F63 function key

clr_bol

el1

cb

Clear to beginning of line

clear_margins

mgc

MC

clear right and left soft margins

set_left_margin

smgl

ML

set left soft margin at current column (not in BSD termcap)

set_right_margin

smgr

MR

set right soft margin at current column

label_format

fln

Lf

label format

set_clock

sclk

SC

set clock, #1 hrs #2 mins #3 secs

display_clock

dclk

DK

display clock

remove_clock

rmclk

RC

remove clock

create_window

cwin

CW

define a window #1 from #2,#3 to #4,#5

goto_window

wingo

WG

go to window #1

hangup

hup

HU

hang-up phone

dial_phone

dial

DI

dial number #1

quick_dial

qdial

QD

dial number #1 without checking

tone

tone

TO

select touch tone dialing

pulse

pulse

PU

select pulse dialing

flash_hook

hook

fh

flash switch hook

fixed_pause

pause

PA

pause for 2-3 seconds

wait_tone

wait

WA

wait for dial-tone

user0

u0

u0

User string #0

user1

u1

u1

User string #1

user2

u2

u2

User string #2

user3

u3

u3

User string #3

user4

u4

u4

User string #4

user5

u5

u5

User string #5

user6

u6

u6

User string #6

user7

u7

u7

User string #7

user8

u8

u8

User string #8

user9

u9

u9

User string #9

orig_pair

op

op

Set default pair to its original value

orig_colors

oc

oc

Set all color pairs to the original ones

initialize_color

initc

Ic

initialize color #1 to (#2,#3,#4)

initialize_pair

initp

Ip

Initialize color pair #1 to fg=(#2,#3,#4), bg=(#5,#6,#7)

set_color_pair

scp

sp

Set current color pair to #1

set_foreground

setf

Sf

Set foreground color #1

set_background

setb

Sb

Set background color #1

change_char_pitch

cpi

ZA

Change number of characters per inch to #1

change_line_pitch

lpi

ZB

Change number of lines per inch to #1

change_res_horz

chr

ZC

Change horizontal resolution to #1

change_res_vert

cvr

ZD

Change vertical resolution to #1

define_char

defc

ZE

Define a character #1, #2 dots wide, descender #3

enter_doublewide_mode

swidm

ZF

Enter double-wide mode

enter_draft_quality

sdrfq

ZG

Enter draft-quality mode

enter_italics_mode

sitm

ZH

Enter italic mode

enter_leftward_mode

slm

ZI

Start leftward carriage motion

enter_micro_mode

smicm

ZJ

Start micro-motion mode

enter_near_letter_quality

snlq

ZK

Enter NLQ mode

enter_normal_quality

snrmq

ZL

Enter normal-quality mode

enter_shadow_mode

sshm

ZM

Enter shadow-print mode

enter_subscript_mode

ssubm

ZN

Enter subscript mode

enter_superscript_mode

ssupm

ZO

Enter superscript mode

enter_upward_mode

sum

ZP

Start upward carriage motion

exit_doublewide_mode

rwidm

ZQ

End double-wide mode

exit_italics_mode

ritm

ZR

End italic mode

exit_leftward_mode

rlm

ZS

End left-motion mode

exit_micro_mode

rmicm

ZT

End micro-motion mode

exit_shadow_mode

rshm

ZU

End shadow-print mode

exit_subscript_mode

rsubm

ZV

End subscript mode

exit_superscript_mode

rsupm

ZW

End superscript mode

exit_upward_mode

rum

ZX

End reverse character motion

micro_column_address

mhpa

ZY

Like column_address in micro mode

micro_down

mcud1

ZZ

Like cursor_down in micro mode

micro_left

mcub1

Za

Like cursor_left in micro mode

micro_right

mcuf1

Zb

Like cursor_right in micro mode

micro_row_address

mvpa

Zc

Like row_address #1 in micro mode

micro_up

mcuu1

Zd

Like cursor_up in micro mode

order_of_pins

porder

Ze

Match software bits to print-head pins

parm_down_micro

mcud

Zf

Like parm_down_cursor in micro mode

parm_left_micro

mcub

Zg

Like parm_left_cursor in micro mode

parm_right_micro

mcuf

Zh

Like parm_right_cursor in micro mode

parm_up_micro

mcuu

Zi

Like parm_up_cursor in micro mode

select_char_set

scs

Zj

Select character set, #1

set_bottom_margin

smgb

Zk

Set bottom margin at current line

set_bottom_margin_parm

smgbp

Zl

Set bottom margin at line #1 or (if smgtp is not given) #2 lines from bottom

set_left_margin_parm

smglp

Zm

Set left (right) margin at column #1

set_right_margin_parm

smgrp

Zn

Set right margin at column #1

set_top_margin

smgt

Zo

Set top margin at current line

set_top_margin_parm

smgtp

Zp

Set top (bottom) margin at row #1

start_bit_image

sbim

Zq

Start printing bit image graphics

start_char_set_def

scsd

Zr

Start character set definition #1, with #2 characters in the set

stop_bit_image

rbim

Zs

Stop printing bit image graphics

stop_char_set_def

rcsd

Zt

End definition of character set #1

subscript_characters

subcs

Zu

List of subscriptable characters

superscript_characters

supcs

Zv

List of superscriptable characters

these_cause_cr

docr

Zw

Printing any of these characters causes CR

zero_motion

zerom

Zx

No motion for subsequent character

The following string capabilities are present in the SVr4.0 term structure, but were originally not documented in the man page.

Code

String Capability Name

TI

TC

Description

char_set_names

csnm

Zy

Produce #1'th item from list of character set names

key_mouse

kmous

Km

Mouse event has occurred

mouse_info

minfo

Mi

Mouse status information

req_mouse_pos

reqmp

RQ

Request mouse position

get_mouse

getm

Gm

Curses should get button events, parameter #1 not documented.

set_a_foreground

setaf

AF

Set foreground color to #1, using ANSI escape

set_a_background

setab

AB

Set background color to #1, using ANSI escape

pkey_plab

pfxl

xl

Program function key #1 to type string #2 and show string #3

device_type

devt

dv

Indicate language, codeset support

code_set_init

csin

ci

Init sequence for multiple codesets

set0_des_seq

s0ds

s0

Shift to codeset 0 (EUC set 0, ASCII)

set1_des_seq

s1ds

s1

Shift to codeset 1

set2_des_seq

s2ds

s2

Shift to codeset 2

set3_des_seq

s3ds

s3

Shift to codeset 3

set_lr_margin

smglr

ML

Set both left and right margins to #1, #2. (ML is not in BSD termcap).

set_tb_margin

smgtb

MT

Sets both top and bottom margins to #1, #2

bit_image_repeat

birep

Xy

Repeat bit image cell #1 #2 times

bit_image_newline

binel

Zz

Move to next row of the bit image

bit_image_carriage_return

bicr

Yv

Move to beginning of same row

color_names

colornm

Yw

Give name for color #1

define_bit_image_region

defbi

Yx

Define rectangular bit image region

end_bit_image_region

endbi

Yy

End a bit-image region

set_color_band

setcolor

Yz

Change to ribbon color #1

set_page_length

slines

YZ

Set page length to #1 lines

display_pc_char

dispc

S1

Display PC character #1

enter_pc_charset_mode

smpch

S2

Enter PC character display mode

exit_pc_charset_mode

rmpch

S3

Exit PC character display mode

enter_scancode_mode

smsc

S4

Enter PC scancode mode

exit_scancode_mode

rmsc

S5

Exit PC scancode mode

pc_term_options

pctrm

S6

PC terminal options

scancode_escape

scesc

S7

Escape for scancode emulation

alt_scancode_esc

scesa

S8

Alternate escape for scancode emulation

The XSI Curses standard added these hardcopy capabilities. They were used in some post-4.1 versions of System V curses, e.g., Solaris 2.5 and IRIX 6.x. Except for YI, the ncurses termcap names for them are invented. According to the XSI Curses standard, they have no termcap names. If your compiled terminfo entries use these, they may not be binary-compatible with System V terminfo entries after SVr4.1; beware!

Code

String Capability Name

TI

TC

Description

enter_horizontal_hl_mode

ehhlm

Xh

Enter horizontal highlight mode

enter_left_hl_mode

elhlm

Xl

Enter left highlight mode

enter_low_hl_mode

elohlm

Xo

Enter low highlight mode

enter_right_hl_mode

erhlm

Xr

Enter right highlight mode

enter_top_hl_mode

ethlm

Xt

Enter top highlight mode

enter_vertical_hl_mode

evhlm

Xv

Enter vertical highlight mode

set_a_attributes

sgr1

sA

Define second set of video attributes #1-#6

set_pglen_inch

slength

YI

Set page length to #1 hundredth of an inch (some implementations use sL for termcap).

### User-Defined Capabilities
The preceding section listed the predefined capabilities. They deal with some special features for terminals no longer (or possibly never) produced. Occasionally there are special features of newer terminals which are awkward or impossible to represent by reusing the predefined capabilities.

ncurses addresses this limitation by allowing user-defined capabilities. The tic and infocmp programs provide the -x option for this purpose. When -x is set, tic treats unknown capabilities as user-defined. That is, if tic encounters a capability name which it does not recognize, it infers its type (Boolean, number or string) from the syntax and makes an extended table entry for that capability. The use_extended_names(3X) function makes this information conditionally available to applications. The ncurses library provides the data leaving most of the behavior to applications:

- User-defined capability strings whose name begins with “k” are treated as function keys.

- The types (Boolean, number, string) determined by tic can be inferred by successful calls on tigetflag, etc.

- If the capability name happens to be two characters, the capability is also available through the termcap interface.

While termcap is said to be extensible because it does not use a predefined set of capabilities, in practice it has been limited to the capabilities defined by terminfo implementations. As a rule, user-defined capabilities intended for use by termcap applications should be limited to Booleans and numbers to avoid running past the 1023 byte limit assumed by termcap implementations and their applications. In particular, providing extended sets of function keys (past the 60 numbered keys and the handful of special named keys) is best done using the longer names available using terminfo.

The ncurses library uses a few of these user-defined capabilities, as described in user_caps(5). Other user-defined capabilities (including function keys) are described in the terminal database, in the section on NCURSES USER-DEFINABLE CAPABILITIES

### A Sample Entry
The following entry, describing an ANSI-standard terminal, is representative of what a terminfo entry for a modern terminal typically looks like.

```
ansi|ansi/pc-term compatible with color,

        am, mc5i, mir, msgr,

        colors#8, cols#80, it#8, lines#24, ncv#3, pairs#64,

        acsc=+\020\,\021-\030.^Y0\333`\004a\261f\370g\361h\260

             j\331k\277l\332m\300n\305o~p\304q\304r\304s_t\303

             u\264v\301w\302x\263y\363z\362{\343|\330}\234~\376,

        bel=^G, blink=\E[5m, bold=\E[1m, cbt=\E[Z, clear=\E[H\E[J,

        cr=^M, cub=\E[%p1%dD, cub1=\E[D, cud=\E[%p1%dB, cud1=\E[B,

        cuf=\E[%p1%dC, cuf1=\E[C, cup=\E[%i%p1%d;%p2%dH,

        cuu=\E[%p1%dA, cuu1=\E[A, dch=\E[%p1%dP, dch1=\E[P,

        dl=\E[%p1%dM, dl1=\E[M, ech=\E[%p1%dX, ed=\E[J, el=\E[K,

        el1=\E[1K, home=\E[H, hpa=\E[%i%p1%dG, ht=\E[I, hts=\EH,

        ich=\E[%p1%d@, il=\E[%p1%dL, il1=\E[L, ind=^J,

        indn=\E[%p1%dS, invis=\E[8m, kbs=^H, kcbt=\E[Z, kcub1=\E[D,

        kcud1=\E[B, kcuf1=\E[C, kcuu1=\E[A, khome=\E[H, kich1=\E[L,

        mc4=\E[4i, mc5=\E[5i, nel=\r\E[S, op=\E[39;49m,

        rep=%p1%c\E[%p2%{1}%-%db, rev=\E[7m, rin=\E[%p1%dT,

        rmacs=\E[10m, rmpch=\E[10m, rmso=\E[m, rmul=\E[m,

        s0ds=\E(B, s1ds=\E)B, s2ds=\E*B, s3ds=\E+B,

        setab=\E[4%p1%dm, setaf=\E[3%p1%dm,

        sgr=\E[0;10%?%p1%t;7%;

                   %?%p2%t;4%;

                   %?%p3%t;7%;

                   %?%p4%t;5%;

                   %?%p6%t;1%;

                   %?%p7%t;8%;

                   %?%p9%t;11%;m,

        sgr0=\E[0;10m, smacs=\E[11m, smpch=\E[11m, smso=\E[7m,

        smul=\E[4m, tbc=\E[3g, u6=\E[%i%d;%dR, u7=\E[6n,

        u8=\E[?%[;0123456789]c, u9=\E[c, vpa=\E[%i%p1%dd,
```

Entries may continue onto multiple lines by placing white space at the beginning of each line except the first. Comments may be included on lines beginning with “#”. Capabilities in terminfo are of three types:

- Boolean capabilities which 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 which can be used to perform particular terminal operations.

### Types of Capabilities
All capabilities have names. For instance, the fact that ANSI-standard terminals have automatic margins (i.e., an automatic return and line-feed when the end of a line is reached) is indicated by the capability am. Hence the description of ansi includes am. Numeric capabilities are followed by the character “#” and then a positive value. Thus cols, which indicates the number of columns the terminal has, gives the value “80” for ansi. Values for numeric capabilities may be specified in decimal, octal, or hexadecimal, using the C programming language conventions (e.g., 255, 0377 and 0xff or 0xFF).

Finally, string valued capabilities, such as el (clear to end of line sequence) are given by the two-character code, an “=”, and then a string ending at the next following “,”.

A number of escape sequences are provided in the string valued capabilities for easy encoding of characters there:

- Both \E and \e map to an ESCAPE character,

- ^x maps to a control-x for any appropriate x, and

- the sequences

\n, \l, \r, \t, \b, \f, and \s

produce

newline, line-feed, return, tab, backspace, form-feed, and space,

respectively.

X/Open Curses does not say what “appropriate x” might be. In practice, that is a printable ASCII graphic character. The special case “^?” is interpreted as DEL (127). In all other cases, the character value is logically “and”-ed with 0x1f, mapping to ASCII control codes in the range 0 through 31.

Other escapes include

- \^ for ^,

- \\ for \,

- \, for comma,

- \: for :,

- and \0 for null.

\0 will produce \200, which does not terminate a string but behaves as a null character on most terminals, providing CS7 is specified. See stty(1).

The reason for this quirk is to maintain binary compatibility of the compiled terminfo files with other implementations, e.g., the SVr4 systems, which document this. Compiled terminfo files use null-terminated strings, with no lengths. Modifying this would require a new binary format, which would not work with other implementations.

Finally, characters may be given as three octal digits after a \.

A delay in milliseconds may appear anywhere in a string capability, enclosed in $<..> brackets, as in el=\EK$<5>, and padding characters are supplied by tputs(3X) to provide this delay.

- The delay must be a number with at most one decimal place of precision; it may be followed by suffixes “*” or “/” or both.

- A “*” 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. (In the case of insert character, the factor is still the number of lines affected.)

Normally, padding is advisory if the device has the xon capability; it is used for cost computation but does not trigger delays.

•

A “/” suffix indicates that the padding is mandatory and forces a delay of the given number of milliseconds even on devices for which xon is present to indicate flow control.

Sometimes individual capabilities must be commented out. To do this, put a period before the capability name. For example, see the second ind in the example above.

### Fetching Compiled Descriptions
Terminal descriptions in ncurses are stored in terminal databases. These databases, which are found by their pathname, may be configured either as directory trees or hashed databases (see term(5)),

The library uses a compiled-in list of pathnames, which can be overridden by environment variables. Before starting to search, ncurses checks the search list, eliminating duplicates and pathnames where no terminal database is found. The ncurses library reads the first description which passes its consistency checks.

- The environment variable TERMINFO is checked first, for a terminal database containing the terminal description.

- Next, ncurses looks in $HOME/.terminfo for a compiled description.

This is an optional feature which may be omitted entirely from the library, or limited to prevent accidental use by privileged applications.

•

Next, if the environment variable TERMINFO_DIRS is set, ncurses interprets the contents of that variable as a list of colon-separated pathnames of terminal databases to be searched.

An empty pathname (i.e., if the variable begins or ends with a colon, or contains adjacent colons) is interpreted as the system location /usr/share/terminfo.

•

Finally, ncurses searches these compiled-in locations:

- a list of directories (/lib/terminfo:/usr/share/terminfo), and

- the system terminfo directory, /usr/share/terminfo

The TERMINFO variable can contain a terminal description instead of the pathname of a terminal database. If this variable begins with “hex:” or “b64:” then ncurses reads a terminal description from hexadecimal- or base64-encoded data, and if that description matches the name sought, will use that. This encoded data can be set using the “-Q” option of tic or infocmp.

The preceding addresses the usual configuration of ncurses, which uses terminal descriptions prepared in terminfo format. While termcap is less expressive, ncurses can also be configured to read termcap descriptions. In that configuration, it checks the TERMCAP and TERMPATH variables (for content and search path, respectively) after the system terminal database.

### Preparing Descriptions
We now outline 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 terminfo and to build up a description gradually, using partial descriptions with vi or some other screen-oriented program to check that they are correct. Be aware that a very unusual terminal may expose deficiencies in the ability of the terminfo file to describe it or bugs in the screen-handling code of the test program.

To get the padding for insert line right (if the terminal manufacturer did not document it) a severe test is to edit a large file at 9600 baud, delete 16 or so lines from the middle of the screen, then hit the “u” key several times quickly. If the terminal messes up, more padding is usually needed. A similar test can be used for insert character.

### Basic Capabilities
The number of columns on each line for the terminal is given by the cols numeric capability. If the terminal is a CRT, then the number of lines on the screen is given by the lines capability. If the terminal wraps around to the beginning of the next line when it reaches the right margin, then it should have the am capability. If the terminal can clear its screen, leaving the cursor in the home position, then this is given by the clear string capability. If the terminal overstrikes (rather than clearing a position when a character is struck over) then it should have the os capability. If the terminal is a printing terminal, with no soft copy unit, give it both hc and os. (os applies to storage scope terminals, such as TEKTRONIX 4010 series, as well as hard copy and APL terminals.) If there is a code to move the cursor to the left edge of the current line, give this as cr. (Normally this will be carriage return, control/M.) If there is a code to produce an audible signal (bell, beep, etc) give this as bel.

If there is a code to move the cursor one position to the left (such as backspace) that capability should be given as cub1. Similarly, codes to move to the right, up, and down should be given as cuf1, cuu1, and cud1. These local cursor motions should not alter the text they pass over, for example, you would not normally use “cuf1= ” because the space would erase the character moved over.

A very important point here is that the local cursor motions encoded in terminfo are undefined at the left and top edges of a CRT terminal. Programs should never attempt to backspace around the left edge, unless bw is given, and never attempt to go up locally off the top. In order to scroll text up, a program will go to the bottom left corner of the screen and send the ind (index) string.

To scroll text down, a program goes to the top left corner of the screen and sends the ri (reverse index) string. The strings ind and ri are undefined when not on their respective corners of the screen.

Parameterized versions of the scrolling sequences are indn and rin which have the same semantics as ind and ri except that they take one parameter, and scroll that many lines. They are also undefined except at the appropriate edge of the screen.

The am capability tells whether the cursor sticks at the right edge of the screen when text is output, but this does not necessarily apply to a cuf1 from the last column. The only local motion which is defined from the left edge is if bw is given, then a cub1 from the left edge will move to the right edge of the previous line. If bw is not given, the effect is undefined. This is useful for drawing a box around the edge of the screen, for example. If the terminal has switch selectable automatic margins, the terminfo file usually assumes that this is on; i.e., am. If the terminal has a command which moves to the first column of the next line, that command can be given as nel (newline). It does not matter if the command clears the remainder of the current line, so if the terminal has no cr and lf it may still be possible to craft a working nel out of one or both of them.

These capabilities suffice to describe hard-copy and “glass-tty” terminals. Thus the model 33 teletype is described as

```
33|tty33|tty|model 33 teletype,

        bel=^G, cols#72, cr=^M, cud1=^J, hc, ind=^J, os,
```

while the Lear Siegler ADM-3 is described as

```
adm3|3|lsi adm3,

        am, bel=^G, clear=^Z, cols#80, cr=^M, cub1=^H, cud1=^J,

        ind=^J, lines#24,
```

### Parameterized Strings
Cursor addressing and other strings requiring parameters in the terminal are described by a parameterized string capability, with printf-like escapes such as %x in it. For example, to address the cursor, the cup capability is given, using two parameters: the line and column to address to. (Lines and columns are numbered from zero and refer to the physical screen visible to the user, not to any unseen memory.) If the terminal has memory relative cursor addressing, that can be indicated by mrcup.

The parameter mechanism uses a stack and special % codes to manipulate it. Typically a sequence will push one of the parameters onto the stack and then print it in some format. Print (e.g., “%d”) is a special case. Other operations, including “%t” pop their operand from the stack. It is noted that more complex operations are often necessary, e.g., in the sgr string.

The % encodings have the following meanings:

%%

outputs “%”

%[[:]flags][width[.precision]][doxXs]

as in printf(3), flags are [-+#] and space. Use a “:” to allow the next character to be a “-” flag, avoiding interpreting “%-” as an operator.

%c

print pop() like %c in printf

%s

print pop() like %s in printf

%p[1-9]

push i'th parameter

%P[a-z]

set dynamic variable [a-z] to pop()

%g[a-z]

get dynamic variable [a-z] and push it

%P[A-Z]

set static variable [a-z] to pop()

%g[A-Z]

get static variable [a-z] and push it

The terms “static” and “dynamic” are misleading. Historically, these are simply two different sets of variables, whose values are not reset between calls to tparm(3X). However, that fact is not documented in other implementations. Relying on it will adversely impact portability to other implementations:

- SVr2 curses supported dynamic variables. Those are set only by a %P operator. A %g for a given variable without first setting it with %P will give unpredictable results, because dynamic variables are an uninitialized local array on the stack in the tparm function.

- SVr3.2 curses supported static variables. Those are an array in the TERMINAL structure (declared in term.h), and are zeroed automatically when the setupterm function allocates the data.

- SVr4 curses made no further improvements to the dynamic/static variable feature.

- Solaris XPG4 curses does not distinguish between dynamic and static variables. They are the same. Like SVr4 curses, XPG4 curses does not initialize these explicitly.

- Before version 6.3, ncurses stores both dynamic and static variables in persistent storage, initialized to zeros.

- Beginning with version 6.3, ncurses stores static and dynamic variables in the same manner as SVr4.

- Unlike other implementations, ncurses zeros dynamic variables before the first %g or %P operator.

- Like SVr2, the scope of dynamic variables in ncurses is within the current call to tparm. Use static variables if persistent storage is needed.

%'c'

char constant c

%{nn}

integer constant nn

%l

push strlen(pop)

%+, %-, %*, %/, %m

arithmetic (%m is mod): push(pop() op pop())

%&, %|, %^

bit operations (“and”, “or” and exclusive “or”): push(pop() op pop())

%=, %>, %<

logical operations: push(pop() op pop())

%A, %O

logical “and” and “or” operations (for conditionals)

%!, %~

unary operations (logical and bit complement): push(op pop())

%i

add 1 to first two parameters (for ANSI terminals)

%? expr %t thenpart %e elsepart %;

This forms an if-then-else. The %e elsepart is optional. Usually the %? expr part pushes a value onto the stack, and %t pops it from the stack, testing if it is nonzero (true). If it is zero (false), control passes to the %e (else) part.

It is possible to form else-if's a la Algol 68:

%? c1 %t b1 %e c2 %t b2 %e c3 %t b3 %e c4 %t b4 %e %;

where ci are conditions, bi are bodies.

Use the -f option of tic or infocmp to see the structure of if-then-else's. Some strings, e.g., sgr can be very complicated when written on one line. The -f option splits the string into lines with the parts indented.

Binary operations are in postfix form with the operands in the usual order. That is, to get x-5 one would use “%gx%{5}%-”. %P and %g variables are persistent across escape-string evaluations.

Consider the HP2645, which, to get to line 3 and column 12, needs to be sent \E&a12c03Y padded for 6 milliseconds. The order of the lines and columns is inverted here, and the lines and column are printed as two digits. The corresponding terminal description is expressed thus:

cup=\E&a%p2%dc%p1%dY$<6>,

The Microterm ACT-IV needs the current line and column sent preceded by a ^T, with the line and column simply encoded in binary,

cup=^T%p1%c%p2%c

Terminals which use “%c” need to be able to backspace the cursor (cub1), and to move the cursor up one line on the screen (cuu1). This is necessary because it is not always safe to transmit \n ^D and \r, as the system may change or discard them. (The library routines dealing with terminfo set tty modes so that tabs are never expanded, so \t is safe to send. This turns out to be essential for the Ann Arbor 4080.)

A final example is the LSI ADM-3A, which uses line and column offset by a space, thus

```
cup=\E=%p1%' '%+%c%p2%' '%+%c
```

After sending “\E=”, this pushes the first parameter, pushes the ASCII value for a space (32), adds them (pushing the sum on the stack in place of the two previous values) and outputs that value as a character. Then the same is done for the second parameter. More complex arithmetic is possible using the stack.

### Cursor Motions
If the terminal has a fast way to home the cursor (to very upper left corner of screen) then this can be given as home; similarly a fast way of getting to the lower left-hand corner can be given as ll; this may involve going up with cuu1 from the home position, but a program should never do this itself (unless ll does) because it can make no assumption about the effect of moving up from the home position. Note that the home position is the same as addressing to (0,0): to the top left corner of the screen, not of memory. (Thus, the \EH sequence on HP terminals cannot be used for home.)

If the terminal has line or column absolute cursor addressing, these can be given as single parameter capabilities hpa (horizontal position absolute) and vpa (vertical position absolute). Sometimes these are shorter than the more general two parameter sequence (as with the hp2645) and can be used in preference to cup. If there are parameterized local motions (e.g., move n spaces to the right) these can be given as cud, cub, cuf, and cuu with a single parameter indicating how many spaces to move. These are primarily useful if the terminal does not have cup, such as the TEKTRONIX 4025.

If the terminal needs to be in a special mode when running a program that uses these capabilities, the codes to enter and exit this mode can be given as smcup and rmcup. This arises, for example, from terminals like the Concept with more than one page of memory. If the terminal has only memory relative cursor addressing and not screen relative cursor addressing, a one screen-sized window must be fixed into the terminal for cursor addressing to work properly. This is also used for the TEKTRONIX 4025, where smcup sets the command character to be the one used by terminfo. If the smcup sequence will not restore the screen after an rmcup sequence is output (to the state prior to outputting rmcup), specify nrrmc.

### Margins
SVr4 (and X/Open Curses) list several string capabilities for setting margins. Two were intended for use with terminals, and another six were intended for use with printers.

- The two terminal capabilities assume that the terminal may have the capability of setting the left and/or right margin at the current cursor column position.

- The printer capabilities assume that the printer may have two types of capability:

- the ability to set a top and/or bottom margin using the current line position, and

- parameterized capabilities for setting the top, bottom, left, right margins given the number of lines or columns.

In practice, the categorization into “terminal” and “printer” is not suitable:

•

The AT&T SVr4 terminal database uses smgl four times, for AT&T hardware.

Three of the four are printers. They lack the ability to set left/right margins by specifying the column.

•

Other (non-AT&T) terminals may support margins but using different assumptions from AT&T.

For instance, the DEC VT420 supports left/right margins, but only using a column parameter. As an added complication, the VT420 uses two settings to fully enable left/right margins (left/right margin mode, and origin mode). The former enables the margins, which causes printed text to wrap within margins, but the latter is needed to prevent cursor-addressing outside those margins.

•

Both DEC VT420 left/right margins are set with a single control sequence. If either is omitted, the corresponding margin is set to the left or right edge of the display (rather than leaving the margin unmodified).

These are the margin-related capabilities:

Name

Description

smgl

Set left margin at current column

smgr

Set right margin at current column

smgb

Set bottom margin at current line

smgt

Set top margin at current line

smgbp

Set bottom margin at line N

smglp

Set left margin at column N

smgrp

Set right margin at column N

smgtp

Set top margin at line N

smglr

Set both left and right margins to L and R

smgtb

Set both top and bottom margins to T and B

When writing an application that uses these string capabilities, the pairs should be first checked to see if each capability in the pair is set or only one is set:

- If both smglp and smgrp are set, each is used with a single argument, N, that gives the column number of the left and right margin, respectively.

- If both smgtp and smgbp are set, each is used to set the top and bottom margin, respectively:

- smgtp is used with a single argument, N, the line number of the top margin.

- smgbp is used with two arguments, N and M, that give the line number of the bottom margin, the first counting from the top of the page and the second counting from the bottom. This accommodates the two styles of specifying the bottom margin in different manufacturers' printers.

When designing a terminfo entry for a printer that has a settable bottom margin, only the first or second argument should be used, depending on the printer. When developing an application that uses smgbp to set the bottom margin, both arguments must be given.

Conversely, when only one capability in the pair is set:

- If only one of smglp and smgrp is set, then it is used with two arguments, the column number of the left and right margins, in that order.

- Likewise, if only one of smgtp and smgbp is set, then it is used with two arguments that give the top and bottom margins, in that order, counting from the top of the page.

When designing a terminfo entry for a printer that requires setting both left and right or top and bottom margins simultaneously, only one capability in the pairs smglp and smgrp or smgtp and smgbp should be defined, leaving the other unset.

Except for very old terminal descriptions, e.g., those developed for SVr4, the scheme just described should be considered obsolete. An improved set of capabilities was added late in the SVr4 releases (smglr and smgtb), which explicitly use two parameters for setting the left/right or top/bottom margins.

When setting margins, the line- and column-values are zero-based.

The mgc string capability should be defined. Applications such as tabs(1) rely upon this to reset all margins.

### Area Clears
If the terminal can clear from the current position to the end of the line, leaving the cursor where it is, this should be given as el. If the terminal can clear from the beginning of the line to the current position inclusive, leaving the cursor where it is, this should be given as el1. If the terminal can clear from the current position to the end of the display, then this should be given as ed. Ed is only defined from the first column of a line. (Thus, it can be simulated by a request to delete a large number of lines, if a true ed is not available.)

### Insert/Delete Line and Vertical Motions
If the terminal can open a new blank line before the line where the cursor is, this should be given as il1; this is done only from the first position of a line. The cursor must then appear on the newly blank line. If the terminal can delete the line which the cursor is on, then this should be given as dl1; this is done only from the first position on the line to be deleted. Versions of il1 and dl1 which take a single parameter and insert or delete that many lines can be given as il and dl.

If the terminal has a settable scrolling region (like the vt100) the command to set this can be described with the csr capability, which takes two parameters: the top and bottom lines of the scrolling region. The cursor position is, alas, undefined after using this command.

It is possible to get the effect of insert or delete line using csr on a properly chosen region; the sc and rc (save and restore cursor) commands may be useful for ensuring that your synthesized insert/delete string does not move the cursor. (Note that the ncurses(3X) library does this synthesis automatically, so you need not compose insert/delete strings for an entry with csr).

Yet another way to construct insert and delete might be to use a combination of index with the memory-lock feature found on some terminals (like the HP-700/90 series, which however also has insert/delete).

Inserting lines at the top or bottom of the screen can also be done using ri or ind on many terminals without a true insert/delete line, and is often faster even on terminals with those features.

The Boolean non_dest_scroll_region should be set if each scrolling window is effectively a view port on a screen-sized canvas. To test for this capability, create a scrolling region in the middle of the screen, write something to the bottom line, move the cursor to the top of the region, and do ri followed by dl1 or ind. If the data scrolled off the bottom of the region by the ri re-appears, then scrolling is non-destructive. System V and X/Open Curses expect that ind, ri, indn, and rin will simulate destructive scrolling; their documentation cautions you not to define csr unless this is true. This curses implementation is more liberal and will do explicit erases after scrolling if ndsrc is defined.

If the terminal has the ability to define a window as part of memory, which all commands affect, it should be given as the parameterized string wind. The four parameters are the starting and ending lines in memory and the starting and ending columns in memory, in that order.

If the terminal can retain display memory above, then the da capability should be given; if display memory can be retained below, then db should be given. These indicate that deleting a line or scrolling may bring non-blank lines up from below or that scrolling back with ri may bring down non-blank lines.

### Insert/Delete Character
There are two basic kinds of intelligent terminals with respect to insert/delete character which can be described using terminfo. The most common insert/delete character operations affect only the characters on the current line and shift characters off the end of the line rigidly. Other terminals, such as the Concept 100 and the Perkin Elmer Owl, make a distinction between typed and untyped blanks on the screen, shifting upon an insert or delete only to an untyped blank on the screen which is either eliminated, or expanded to two untyped blanks.

You can determine the kind of terminal you have by clearing the screen and then typing text separated by cursor motions. Type “abc def” using local cursor motions (not spaces) between the “abc” and the “def”. Then position the cursor before the “abc” and put the terminal in insert mode. If typing characters causes the rest of the line to shift rigidly and characters to fall off the end, then your terminal does not distinguish between blanks and untyped positions. If the “abc” shifts over to the “def” which then move together around the end of the current line and onto the next as you insert, you have the second type of terminal, and should give the capability in, which stands for “insert null”.

While these are two logically separate attributes (one line versus multi-line insert mode, and special treatment of untyped spaces) we have seen no terminals whose insert mode cannot be described with the single attribute.

Terminfo can describe both terminals which have an insert mode, and terminals which send a simple sequence to open a blank position on the current line. Give as smir the sequence to get into insert mode. Give as rmir the sequence to leave insert mode. Now give as ich1 any sequence needed to be sent just before sending the character to be inserted. Most terminals with a true insert mode will not give ich1; terminals which send a sequence to open a screen position should give it here.

If your terminal has both, insert mode is usually preferable to ich1. Technically, you should not give both unless the terminal actually requires both to be used in combination. Accordingly, some non-curses applications get confused if both are present; the symptom is doubled characters in an update using insert. This requirement is now rare; most ich sequences do not require previous smir, and most smir insert modes do not require ich1 before each character. Therefore, the new curses actually assumes this is the case and uses either rmir/smir or ich/ich1 as appropriate (but not both). If you have to write an entry to be used under new curses for a terminal old enough to need both, include the rmir/smir sequences in ich1.

If post insert padding is needed, give this as a number of milliseconds in ip (a string option). Any other sequence which may need to be sent after an insert of a single character may also be given in ip. If your terminal needs both to be placed into an “insert mode” and a special code to precede each inserted character, then both smir/rmir and ich1 can be given, and both will be used. The ich capability, with one parameter, n, will repeat the effects of ich1 n times.

If padding is necessary between characters typed while not in insert mode, give this as a number of milliseconds padding in rmp.

It is occasionally necessary to move around while in insert mode to delete characters on the same line (e.g., if there is a tab after the insertion position). If your terminal allows motion while in insert mode you can give the capability mir to speed up inserting in this case. Omitting mir will affect only speed. Some terminals (notably Datamedia's) must not have mir because of the way their insert mode works.

Finally, you can specify dch1 to delete a single character, dch with one parameter, n, to delete n characters, and delete mode by giving smdc and rmdc to enter and exit delete mode (any mode the terminal needs to be placed in for dch1 to work).

A command to erase n characters (equivalent to outputting n blanks without moving the cursor) can be given as ech with one parameter.

### Highlighting, Underlining, and Visible Bells
If your terminal has one or more kinds of display attributes, these can be represented in a number of different ways. You should choose one display form as standout mode, representing a good, high contrast, easy-on-the-eyes, format for highlighting error messages and other attention getters. (If you have a choice, reverse video plus half-bright is good, or reverse video alone.) The sequences to enter and exit standout mode are given as smso and rmso, respectively. If the code to change into or out of standout mode leaves one or even two blank spaces on the screen, as the TVI 912 and Teleray 1061 do, then xmc should be given to tell how many spaces are left.

Codes to begin underlining and end underlining can be given as smul and rmul respectively. If the terminal has a code to underline the current character and move the cursor one space to the right, such as the Microterm Mime, this can be given as uc.

Other capabilities to enter various highlighting modes include blink (blinking) bold (bold or extra bright) dim (dim or half-bright) invis (blanking or invisible text) prot (protected) rev (reverse video) sgr0 (turn off all attribute modes) smacs (enter alternate character set mode) and rmacs (exit alternate character set mode). Turning on any of these modes singly may or may not turn off other modes.

If there is a sequence to set arbitrary combinations of modes, this should be given as sgr (set attributes), taking 9 parameters. Each parameter is either zero (0) or nonzero, as the corresponding attribute is on or off. The 9 parameters are, in order: standout, underline, reverse, blink, dim, bold, blank, protect, alternate character set. Not all modes need be supported by sgr, only those for which corresponding separate attribute commands exist.

For example, the DEC vt220 supports most of the modes:

tparm Parameter

Attribute

Escape Sequence

none

none

\E[0m

p1

standout

\E[0;1;7m

p2

underline

\E[0;4m

p3

reverse

\E[0;7m

p4

blink

\E[0;5m

p5

dim

not available

p6

bold

\E[0;1m

p7

invis

\E[0;8m

p8

protect

not used

p9

altcharset

^O (off) ^N (on)

We begin each escape sequence by turning off any existing modes, since there is no quick way to determine whether they are active. Standout is set up to be the combination of reverse and bold. The vt220 terminal has a protect mode, though it is not commonly used in sgr because it protects characters on the screen from the host's erasures. The altcharset mode also is different in that it is either ^O or ^N, depending on whether it is off or on. If all modes are turned on, the resulting sequence is \E[0;1;4;5;7;8m^N.

Some sequences are common to different modes. For example, ;7 is output when either p1 or p3 is true, that is, if either standout or reverse modes are turned on.

Writing out the above sequences, along with their dependencies yields

Sequence

When to Output

terminfo Translation

\E[0

always

\E[0

;1

if p1 or p6

%?%p1%p6%|%t;1%;

;4

if p2

%?%p2%|%t;4%;

;5

if p4

%?%p4%|%t;5%;

;7

if p1 or p3

%?%p1%p3%|%t;7%;

;8

if p7

%?%p7%|%t;8%;

m

always

m

^N or ^O

if p9 ^N, else ^O

%?%p9%t^N%e^O%;

Putting this all together into the sgr sequence gives:

```
    sgr=\E[0%?%p1%p6%|%t;1%;%?%p2%t;4%;%?%p4%t;5%;

        %?%p1%p3%|%t;7%;%?%p7%t;8%;m%?%p9%t\016%e\017%;,
```

Remember that if you specify sgr, you must also specify sgr0. Also, some implementations rely on sgr being given if sgr0 is, Not all terminfo entries necessarily have an sgr string, however. Many terminfo entries are derived from termcap entries which have no sgr string. The only drawback to adding an sgr string is that termcap also assumes that sgr0 does not exit alternate character set mode.

Terminals with the “magic cookie” glitch (xmc) deposit special “cookies” when they receive mode-setting sequences, which affect the display algorithm rather than having extra bits for each character. Some terminals, such as the HP 2621, automatically leave standout mode when they move to a new line or the cursor is addressed. Programs using standout mode should exit standout mode before moving the cursor or sending a newline, unless the msgr capability, asserting that it is safe to move in standout mode, is present.

If the terminal has a way of flashing the screen to indicate an error quietly (a bell replacement) then this can be given as flash; it must not move the cursor.

If the cursor needs to be made more visible than normal when it is not on the bottom line (to make, for example, a non-blinking underline into an easier to find block or blinking underline) give this sequence as cvvis. If there is a way to make the cursor completely invisible, give that as civis. The capability cnorm should be given which undoes the effects of both of these modes.

If your terminal correctly generates underlined characters (with no special codes needed) even though it does not overstrike, then you should give the capability ul. If a character overstriking another leaves both characters on the screen, specify the capability os. If overstrikes are erasable with a blank, then this should be indicated by giving eo.

### Keypad and Function Keys
If the terminal has a keypad that transmits codes when the keys are pressed, this information can be given. Note that it is not possible to handle terminals where the keypad only works in local (this applies, for example, to the unshifted HP 2621 keys). If the keypad can be set to transmit or not transmit, give these codes as smkx and rmkx. Otherwise the keypad is assumed to always transmit.

The codes sent by the left arrow, right arrow, up arrow, down arrow, and home keys can be given as kcub1, kcuf1, kcuu1, kcud1, and khome respectively. If there are function keys such as f0, f1, ..., f10, the codes they send can be given as kf0, kf1, ..., kf10. If these keys have labels other than the default f0 through f10, the labels can be given as lf0, lf1, ..., lf10.

The codes transmitted by certain other special keys can be given:

- kll (home down),

- kbs (backspace),

- ktbc (clear all tabs),

- kctab (clear the tab stop in this column),

- kclr (clear screen or erase key),

- kdch1 (delete character),

- kdl1 (delete line),

- krmir (exit insert mode),

- kel (clear to end of line),

- ked (clear to end of screen),

- kich1 (insert character or enter insert mode),

- kil1 (insert line),

- knp (next page),

- kpp (previous page),

- kind (scroll forward/down),

- kri (scroll backward/up),

- khts (set a tab stop in this column).

In addition, if the keypad has a 3 by 3 array of keys including the four arrow keys, the other five keys can be given as ka1, ka3, kb2, kc1, and kc3. These keys are useful when the effects of a 3 by 3 directional pad are needed.

Strings to program function keys can be given as pfkey, pfloc, and pfx. A string to program screen labels should be specified as pln. Each of these strings takes two parameters: the function key number to program (from 0 to 10) and the string to program it with. Function key numbers out of this range may program undefined keys in a terminal dependent manner. The difference between the capabilities is that pfkey causes pressing the given key to be the same as the user typing the given string; pfloc causes the string to be executed by the terminal in local; and pfx causes the string to be transmitted to the computer.

The capabilities nlab, lw and lh define the number of programmable screen labels and their width and height. If there are commands to turn the labels on and off, give them in smln and rmln. smln is normally output after one or more pln sequences to make sure that the change becomes visible.

### Tabs and Initialization
A few capabilities are used only for tabs:

- If the terminal has hardware tabs, the command to advance to the next tab stop can be given as ht (usually control/I).

- A “back-tab” command which moves leftward to the preceding tab stop can be given as cbt.

By convention, if the teletype modes indicate that tabs are being expanded by the computer rather than being sent to the terminal, programs should not use ht or cbt even if they are present, since the user may not have the tab stops properly set.

•

If the terminal has hardware tabs which are initially set every n spaces when the terminal is powered up, the numeric parameter it is given, showing the number of spaces the tabs are set to.

The it capability is normally used by the tset command to determine whether to set the mode for hardware tab expansion, and whether to set the tab stops. If the terminal has tab stops that can be saved in non-volatile memory, the terminfo description can assume that they are properly set.

Other capabilities include

- is1, is2, and is3, initialization strings for the terminal,

- iprog, the path name of a program to be run to initialize the terminal,

- and if, the name of a file containing long initialization strings.

These strings are expected to set the terminal into modes consistent with the rest of the terminfo description. They are normally sent to the terminal, by the init option of the tput program, each time the user logs in. They will be printed in the following order:

run the program

iprog

output

is1 and

is2

set the margins using

mgc or

smglp and smgrp or

smgl and smgr

set tabs using

tbc and hts

print the file

if

and finally output

is3.

Most initialization is done with is2. Special terminal modes can be set up without duplicating strings by putting the common sequences in is2 and special cases in is1 and is3.

A set of sequences that does a harder reset from a totally unknown state can be given as rs1, rs2, rf and rs3, analogous to is1 , is2 , if and is3 respectively. These strings are output by reset option of tput, or by the reset program (an alias of tset), which is used when the terminal gets into a wedged state. Commands are normally placed in rs1, rs2 rs3 and rf only if they produce annoying effects on the screen and are not necessary when logging in. For example, the command to set the vt100 into 80-column mode would normally be part of is2, but it causes an annoying glitch of the screen and is not normally needed since the terminal is usually already in 80-column mode.

The reset program writes strings including iprog, etc., in the same order as the init program, using rs1, etc., instead of is1, etc. If any of rs1, rs2, rs3, or rf reset capability strings are missing, the reset program falls back upon the corresponding initialization capability string.

If there are commands to set and clear tab stops, they can be given as tbc (clear all tab stops) and hts (set a tab stop in the current column of every line). If a more complex sequence is needed to set the tabs than can be described by this, the sequence can be placed in is2 or if.

The tput reset command uses the same capability strings as the reset command, although the two programs (tput and reset) provide different command-line options.

In practice, these terminfo capabilities are not often used in initialization of tabs (though they are required for the tabs program):

•

Almost all hardware terminals (at least those which supported tabs) initialized those to every eight columns:

The only exception was the AT&T 2300 series, which set tabs to every five columns.

- In particular, developers of the hardware terminals which are commonly used as models for modern terminal emulators provided documentation demonstrating that eight columns were the standard.

- Because of this, the terminal initialization programs tput and tset use the tbc (clear_all_tabs) and hts (set_tab) capabilities directly only when the it (init_tabs) capability is set to a value other than eight.

### Delays and Padding
Many older and slower terminals do not support either XON/XOFF or DTR handshaking, including hard copy terminals and some very archaic CRTs (including, for example, DEC VT100s). These may require padding characters after certain cursor motions and screen changes.

If the terminal uses xon/xoff handshaking for flow control (that is, it automatically emits ^S back to the host when its input buffers are close to full), set xon. This capability suppresses the emission of padding. You can also set it for memory-mapped console devices effectively that do not have a speed limit. Padding information should still be included so that routines can make better decisions about relative costs, but actual pad characters will not be transmitted.

If pb (padding baud rate) is given, padding is suppressed at baud rates below the value of pb. If the entry has no padding baud rate, then whether padding is emitted or not is completely controlled by xon.

If the terminal requires other than a null (zero) character as a pad, then this can be given as pad. Only the first character of the pad string is used.

### Status Lines
Some terminals have an extra “status line” which is not normally used by software (and thus not counted in the terminal's lines capability).

The simplest case is a status line which is cursor-addressable but not part of the main scrolling region on the screen; the Heathkit H19 has a status line of this kind, as would a 24-line VT100 with a 23-line scrolling region set up on initialization. This situation is indicated by the hs capability.

Some terminals with status lines need special sequences to access the status line. These may be expressed as a string with single parameter tsl which takes the cursor to a given zero-origin column on the status line. The capability fsl must return to the main-screen cursor positions before the last tsl. You may need to embed the string values of sc (save cursor) and rc (restore cursor) in tsl and fsl to accomplish this.

The status line is normally assumed to be the same width as the width of the terminal. If this is untrue, you can specify it with the numeric capability wsl.

A command to erase or blank the status line may be specified as dsl.

The Boolean capability eslok specifies that escape sequences, tabs, etc., work ordinarily in the status line.

The ncurses implementation does not yet use any of these capabilities. They are documented here in case they ever become important.

### Line Graphics
Many terminals have alternate character sets useful for forms-drawing. Terminfo and curses have built-in support for most of the drawing characters supported by the VT100, with some characters from the AT&T 4410v1 added. This alternate character set may be specified by the acsc capability.

acsc

ACS Name

Value

Symbol

ASCII Fallback / Glyph Name

ACS_RARROW

0x2b

+

>

arrow pointing right

ACS_LARROW

0x2c

,

<

arrow pointing left

ACS_UARROW

0x2d

-

^

arrow pointing up

ACS_DARROW

0x2e

.

v

arrow pointing down

ACS_BLOCK

0x30

0

\#

solid square block

ACS_DIAMOND

0x60

`

+

diamond

ACS_CKBOARD

0x61

a

:

checker board (stipple)

ACS_DEGREE

0x66

f

\

degree symbol

ACS_PLMINUS

0x67

g

\#

plus/minus

ACS_BOARD

0x68

h

\#

board of squares

ACS_LANTERN

0x69

i

\#

lantern symbol

ACS_LRCORNER

0x6a

j

+

lower right corner

ACS_URCORNER

0x6b

k

+

upper right corner

ACS_ULCORNER

0x6c

l

+

upper left corner

ACS_LLCORNER

0x6d

m

+

lower left corner

ACS_PLUS

0x6e

n

+

large plus or crossover

ACS_S1

0x6f

o

~

scan line 1

ACS_S3

0x70

p

-

scan line 3

ACS_HLINE

0x71

q

-

horizontal line

ACS_S7

0x72

r

-

scan line 7

ACS_S9

0x73

s

_

scan line 9

ACS_LTEE

0x74

t

+

tee pointing right

ACS_RTEE

0x75

u

+

tee pointing left

ACS_BTEE

0x76

v

+

tee pointing up

ACS_TTEE

0x77

w

+

tee pointing down

ACS_VLINE

0x78

x

|

vertical line

ACS_LEQUAL

0x79

y

<

less-than-or-equal-to

ACS_GEQUAL

0x7a

z

>

greater-than-or-equal-to

ACS_PI

0x7b

{

*

greek pi

ACS_NEQUAL

0x7c

|

!

not-equal

ACS_STERLING

0x7d

}

f

UK pound sign

ACS_BULLET

0x7e

~

o

bullet

A few notes apply to the table itself:

- X/Open Curses incorrectly states that the mapping for lantern is uppercase “I” although Unix implementations use the lowercase “i” mapping.

- The DEC VT100 implemented graphics using the alternate character set feature, temporarily switching modes and sending characters in the range 0x60 (96) to 0x7e (126) (the acsc Value column in the table).

- The AT&T terminal added graphics characters outside that range.

Some of the characters within the range do not match the VT100; presumably they were used in the AT&T terminal: board of squares replaces the VT100 newline symbol, while lantern symbol replaces the VT100 vertical tab symbol. The other VT100 symbols for control characters (horizontal tab, carriage return and line-feed) are not (re)used in curses.

The best way to define a new device's graphics set is to add a column to a copy of this table for your terminal, giving the character which (when emitted between smacs/rmacs switches) will be rendered as the corresponding graphic. Then read off the VT100/your terminal character pairs right to left in sequence; these become the ACSC string.

### Color Handling
The curses library functions init_pair and init_color manipulate the color pairs and color values discussed in this section (see curs_color(3X) for details on these and related functions).

Most color terminals are either “Tektronix-like” or “HP-like”:

- Tektronix-like terminals have a predefined set of N colors (where N is usually 8), and can set character-cell foreground and background colors independently, mixing them into N * N color pairs.

- On HP-like terminals, the user must set each color pair up separately (foreground and background are not independently settable). Up to M color pairs may be set up from 2*M different colors. ANSI-compatible terminals are Tektronix-like.

Some basic color capabilities are independent of the color method. The numeric capabilities colors and pairs specify the maximum numbers of colors and color pairs that can be displayed simultaneously. The op (original pair) string resets foreground and background colors to their default values for the terminal. The oc string resets all colors or color pairs to their default values for the terminal. Some terminals (including many PC terminal emulators) erase screen areas with the current background color rather than the power-up default background; these should have the Boolean capability bce.

While the curses library works with color pairs (reflecting the inability of some devices to set foreground and background colors independently), there are separate capabilities for setting these features:

- To change the current foreground or background color on a Tektronix-type terminal, use setaf (set ANSI foreground) and setab (set ANSI background) or setf (set foreground) and setb (set background). These take one parameter, the color number. The SVr4 documentation describes only setaf/setab; the XPG4 draft says that "If the terminal supports ANSI escape sequences to set background and foreground, they should be coded as setaf and setab, respectively.

- If the terminal supports other escape sequences to set background and foreground, they should be coded as setf and setb, respectively. The vidputs and the refresh(3X) functions use the setaf and setab capabilities if they are defined.

The setaf/setab and setf/setb capabilities take a single numeric argument each. Argument values 0-7 of setaf/setab are portably defined as follows (the middle column is the symbolic #define available in the header for the curses or ncurses libraries). The terminal hardware is free to map these as it likes, but the RGB values indicate normal locations in color space.

Color

\#define

Value

RGB

black

COLOR_BLACK

0

0,

0,

0

red

COLOR_RED

1

max,

0,

0

green

COLOR_GREEN

2

0,

max,

0

yellow

COLOR_YELLOW

3

max,

max,

0

blue

COLOR_BLUE

4

0,

0,

max

magenta

COLOR_MAGENTA

5

max,

0,

max

cyan

COLOR_CYAN

6

0,

max,

max

white

COLOR_WHITE

7

max,

max,

max

The argument values of setf/setb historically correspond to a different mapping, i.e.,

Color

\#define

Value

RGB

black

COLOR_BLACK

0

0,

0,

0

blue

COLOR_BLUE

1

0,

0,

max

green

COLOR_GREEN

2

0,

max,

0

cyan

COLOR_CYAN

3

0,

max,

max

red

COLOR_RED

4

max,

0,

0

magenta

COLOR_MAGENTA

5

max,

0,

max

yellow

COLOR_YELLOW

6

max,

max,

0

white

COLOR_WHITE

7

max,

max,

max

It is important to not confuse the two sets of color capabilities; otherwise red/blue will be interchanged on the display.

On an HP-like terminal, use scp with a color pair number parameter to set which color pair is current.

Some terminals allow the color values to be modified:

- On a Tektronix-like terminal, the capability ccc may be present to indicate that colors can be modified. If so, the initc capability will take a color number (0 to colors - 1)and three more parameters which describe the color. These three parameters default to being interpreted as RGB (Red, Green, Blue) values. If the Boolean capability hls is present, they are instead as HLS (Hue, Lightness, Saturation) indices. The ranges are terminal-dependent.

- On an HP-like terminal, initp may give a capability for changing a color pair value. It will take seven parameters; a color pair number (0 to max_pairs - 1), and two triples describing first background and then foreground colors. These parameters must be (Red, Green, Blue) or (Hue, Lightness, Saturation) depending on hls.

On some color terminals, colors collide with highlights. You can register these collisions with the ncv capability. This is a bit mask of attributes not to be used when colors are enabled. The correspondence with the attributes understood by curses is as follows:

Attribute

Bit

Decimal

Set by

A_STANDOUT

0

1

sgr

A_UNDERLINE

1

2

sgr

A_REVERSE

2

4

sgr

A_BLINK

3

8

sgr

A_DIM

4

16

sgr

A_BOLD

5

32

sgr

A_INVIS

6

64

sgr

A_PROTECT

7

128

sgr

A_ALTCHARSET

8

256

sgr

A_HORIZONTAL

9

512

sgr1

A_LEFT

10

1024

sgr1

A_LOW

11

2048

sgr1

A_RIGHT

12

4096

sgr1

A_TOP

13

8192

sgr1

A_VERTICAL

14

16384

sgr1

A_ITALIC

15

32768

sitm

For example, on many IBM PC consoles, the underline attribute collides with the foreground color blue and is not available in color mode. These should have an ncv capability of 2.

SVr4 curses does nothing with ncv, ncurses recognizes it and optimizes the output in favor of colors.

### Miscellaneous
If the terminal requires other than a null (zero) character as a pad, then this can be given as pad. Only the first character of the pad string is used. If the terminal does not have a pad character, specify npc. Note that ncurses implements the termcap-compatible PC variable; though the application may set this value to something other than a null, ncurses will test npc first and use napms if the terminal has no pad character.

If the terminal can move up or down half a line, this can be indicated with hu (half-line up) and hd (half-line down). This is primarily useful for superscripts and subscripts on hard-copy terminals. If a hard-copy terminal can eject to the next page (form feed), give this as ff (usually control/L).

If there is a command to repeat a given character a given number of times (to save time transmitting a large number of identical characters) this can be indicated with the parameterized string rep. The first parameter is the character to be repeated and the second is the number of times to repeat it. Thus, tparm(repeat_char, 'x', 10) is the same as “xxxxxxxxxx”.

If the terminal has a settable command character, such as the TEKTRONIX 4025, this can be indicated with cmdch. A prototype command character is chosen which is used in all capabilities. This character is given in the cmdch capability to identify it. The following convention is supported on some Unix systems: The environment is to be searched for a CC variable, and if found, all occurrences of the prototype character are replaced with the character in the environment variable.

Terminal descriptions that do not represent a specific kind of known terminal, such as switch, dialup, patch, and network, should include the gn (generic) capability so that programs can complain that they do not know how to talk to the terminal. (This capability does not apply to virtual terminal descriptions for which the escape sequences are known.)

If the terminal has a “meta key” which acts as a shift key, setting the 8th bit of any character transmitted, this fact can be indicated with km. Otherwise, software will assume that the 8th bit is parity and it will usually be cleared. If strings exist to turn this “meta mode” on and off, they can be given as smm and rmm.

If the terminal has more lines of memory than will fit on the screen at once, the number of lines of memory can be indicated with lm. A value of lm#0 indicates that the number of lines is not fixed, but that there is still more memory than fits on the screen.

If the terminal is one of those supported by the Unix virtual terminal protocol, the terminal number can be given as vt.

Media copy strings which control an auxiliary printer connected to the terminal can be given as mc0: print the contents of the screen, mc4: turn off the printer, and mc5: turn on the printer. When the printer is on, all text sent to the terminal will be sent to the printer. It is undefined whether the text is also displayed on the terminal screen when the printer is on. A variation mc5p takes one parameter, and leaves the printer on for as many characters as the value of the parameter, then turns the printer off. The parameter should not exceed 255. All text, including mc4, is transparently passed to the printer while an mc5p is in effect.

### Glitches and Brain Damage
Hazeltine terminals, which do not allow “~” characters to be displayed should indicate hz.

Terminals which ignore a line-feed immediately after an am wrap, such as the Concept and vt100, should indicate xenl.

If el is required to get rid of standout (instead of merely writing normal text on top of it), xhp should be given.

Teleray terminals, where tabs turn all characters moved over to blanks, should indicate xt (destructive tabs). Note: the variable indicating this is now “dest_tabs_magic_smso”; in older versions, it was teleray_glitch. This glitch is also taken to mean that it is not possible to position the cursor on top of a “magic cookie”, that to erase standout mode it is instead necessary to use delete and insert line. The ncurses implementation ignores this glitch.

The Beehive Superbee, which is unable to correctly transmit the escape or control/C characters, has xsb, indicating that the f1 key is used for escape and f2 for control/C. (Only certain Superbees have this problem, depending on the ROM.) Note that in older terminfo versions, this capability was called “beehive_glitch”; it is now “no_esc_ctl_c”.

Other specific terminal problems may be corrected by adding more capabilities of the form xx.

### Pitfalls of Long Entries
Long terminfo entries are unlikely to be a problem; to date, no entry has even approached terminfo's 4096-byte string-table maximum. Unfortunately, the termcap translations are much more strictly limited (to 1023 bytes), thus termcap translations of long terminfo entries can cause problems.

The man pages for 4.3BSD and older versions of tgetent instruct the user to allocate a 1024-byte buffer for the termcap entry. The entry gets null-terminated by the termcap library, so that makes the maximum safe length for a termcap entry 1k-1 (1023) bytes. Depending on what the application and the termcap library being used does, and where in the termcap file the terminal type that tgetent is searching for is, several bad things can happen:

- some termcap libraries print a warning message,

- some exit if they find an entry that's longer than 1023 bytes,

- some neither exit nor warn, doing nothing useful, and

- some simply truncate the entries to 1023 bytes.

Some application programs allocate more than the recommended 1K for the termcap entry; others do not.

Each termcap entry has two important sizes associated with it: before “tc” expansion, and after “tc” expansion. “tc” is the capability that tacks on another termcap entry to the end of the current one, to add on its capabilities. If a termcap entry does not use the “tc” capability, then of course the two lengths are the same.

The “before tc expansion” length is the most important one, because it affects more than just users of that particular terminal. This is the length of the entry as it exists in /etc/termcap, minus the backslash-newline pairs, which tgetent strips out while reading it. Some termcap libraries strip off the final newline, too (GNU termcap does not). Now suppose:

- a termcap entry before expansion is more than 1023 bytes long,

- and the application has only allocated a 1k buffer,

- and the termcap library (like the one in BSD/OS 1.1 and GNU) reads the whole entry into the buffer, no matter what its length, to see if it is the entry it wants,

- and tgetent is searching for a terminal type that either is the long entry, appears in the termcap file after the long entry, or does not appear in the file at all (so that tgetent has to search the whole termcap file).

Then tgetent will overwrite memory, perhaps its stack, and probably core dump the program. Programs like telnet are particularly vulnerable; modern telnets pass along values like the terminal type automatically. The results are almost as undesirable with a termcap library, like SunOS 4.1.3 and Ultrix 4.4, that prints warning messages when it reads an overly long termcap entry. If a termcap library truncates long entries, like OSF/1 3.0, it is immune to dying here but will return incorrect data for the terminal.

The “after tc expansion” length will have a similar effect to the above, but only for people who actually set TERM to that terminal type, since tgetent only does “tc” expansion once it is found the terminal type it was looking for, not while searching.

In summary, a termcap entry that is longer than 1023 bytes can cause, on various combinations of termcap libraries and applications, a core dump, warnings, or incorrect operation. If it is too long even before “tc” expansion, it will have this effect even for users of some other terminal types and users whose TERM variable does not have a termcap entry.

When in -C (translate to termcap) mode, the ncurses implementation of tic(1M) issues warning messages when the pre-tc length of a termcap translation is too long. The -c (check) option also checks resolved (after tc expansion) lengths.

## FILES
/usr/share/terminfo

compiled terminal description database directory

## EXTENSIONS
Searching for terminal descriptions in $HOME/.terminfo and TERMINFO_DIRS is not supported by older implementations.

Some SVr4 curses implementations, and all previous to SVr4, do not interpret the %A and %O operators in parameter strings.

SVr4/XPG4 do not specify whether msgr licenses movement while in an alternate-character-set mode (such modes may, among other things, map CR and NL to characters that do not trigger local motions). The ncurses implementation ignores msgr in ALTCHARSET mode. This raises the possibility that an XPG4 implementation making the opposite interpretation may need terminfo entries made for ncurses to have msgr turned off.

The ncurses library handles insert-character and insert-character modes in a slightly non-standard way to get better update efficiency. See the Insert/Delete Character subsection above.

The parameter substitutions for set_clock and display_clock are not documented in SVr4 or X/Open Curses. They are deduced from the documentation for the AT&T 505 terminal.

Be careful assigning the kmous capability. The ncurses library wants to interpret it as KEY_MOUSE, for use by terminals and emulators like xterm that can return mouse-tracking information in the keyboard-input stream.

X/Open Curses does not mention italics. Portable applications must assume that numeric capabilities are signed 16-bit values. This includes the no_color_video (ncv) capability. The 32768 mask value used for italics with ncv can be confused with an absent or canceled ncv. If italics should work with colors, then the ncv value must be specified, even if it is zero.

Different commercial ports of terminfo and curses support different subsets of X/Open Curses and (in some cases) different extensions. Here is a summary, accurate as of October 1995, after which the commercial Unix market contracted and lost diversity.

- SVr4, Solaris, and ncurses support all SVr4 capabilities.

- IRIX supports the SVr4 set and adds one undocumented extended string capability (set_pglen).

- SVr1 and Ultrix support a restricted subset of terminfo capabilities. The Booleans end with xon_xoff; the numerics with width_status_line; and the strings with prtr_non.

- HP/UX supports the SVr1 subset, plus the SVr[234] numerics num_labels, label_height, label_width, plus function keys 11 through 63, plus plab_norm, label_on, and label_off, plus a number of incompatible string table extensions.

- AIX supports the SVr1 subset, plus function keys 11 through 63, plus a number of incompatible string table extensions.

- OSF/1 supports both the SVr4 set and the AIX extensions.

## PORTABILITY
Do not count on compiled (binary) terminfo entries being portable between commercial Unix systems. At least two implementations of terminfo (those of HP-UX and AIX) diverged from those of other System V Unices after SVr1, adding extension capabilities to the string table that (in the binary format) collide with subsequent System V and X/Open Curses extensions.

## AUTHORS
Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey. Based on pcurses by Pavel Curtis.

## SEE ALSO
infocmp(1M), tabs(1), tic(1M), curses(3X), curs_color(3X), curs_terminfo(3X), curs_variables(3X), printf(3), term_variables(3X), term(5), user_caps(5)