.\"***************************************************************************
-.\" Copyright 2018-2021,2022 Thomas E. Dickey *
+.\" Copyright 2018-2022,2023 Thomas E. Dickey *
.\" Copyright 1998-2016,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: terminfo.tail,v 1.113 2022/12/10 19:51:10 tom Exp $
+.\" $Id: terminfo.tail,v 1.131 2023/09/16 17:01:55 Branden.Robinson Exp $
.ps +1
.SS User-Defined Capabilities
.
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.
+.PP
+The ncurses library uses a few of these user-defined capabilities,
+as described in \fBuser_caps\fR(5).
+Other user-defined capabilities (including function keys) are
+described in the terminal database, in the section on
+.I "NCURSES USER-DEFINABLE CAPABILITIES"
.
.SS A Sample Entry
.
of what a \fBterminfo\fP entry for a modern terminal typically looks like.
.PP
.nf
-.ft CW
+.ft \*(CW
\s-2ansi|ansi/pc-term compatible with color,
am, mc5i, mir, msgr,
colors#8, cols#80, it#8, lines#24, ncv#3, pairs#64,
string
capabilities, which give a sequence which can be used to perform particular
terminal operations.
-.PP
.SS Types of Capabilities
-.PP
All capabilities have names.
For instance, the fact that
ANSI-standard terminals have
(i.e., an automatic return and line-feed
when the end of a line is reached) is indicated by the capability \fBam\fP.
Hence the description of ansi includes \fBam\fP.
-Numeric capabilities are followed by the character \*(``#\*('' and then a positive value.
+Numeric capabilities are followed by the character \*(``#\*(''
+and then a positive value.
Thus \fBcols\fP, 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).
-.PP
-Finally, string valued capabilities, such as \fBel\fP (clear to end of line
-sequence) are given by the two-character code, an \*(``=\*('', and then a string
-ending at the next following \*(``,\*(''.
+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).
+.PP
+Finally, string valued capabilities,
+such as \fBel\fP (clear to end of line sequence)
+are given by the two-character code,
+an \*(``=\*('', and then
+a string ending at the next following \*(``,\*(''.
.PP
A number of escape sequences are provided in the string valued capabilities
for easy encoding of characters there:
to provide this delay.
.bP
The delay must be a number with at most one decimal
-place of precision; it may be followed by suffixes \*(``*\*('' or \*(``/\*('' or both.
+place of precision;
+it may be followed by suffixes \*(``*\*('' or \*(``/\*('' or both.
.bP
A \*(``*\*(''
indicates that the padding required is proportional to the number of lines
in the example above.
.br
.ne 5
-.PP
.SS Fetching Compiled Descriptions
+Terminal descriptions in \fBncurses\fP are stored in terminal databases.
+These databases, which are found by their pathname,
+may be configured either as directory trees or hashed databases
+(see \fBterm\fR(\*n)),
.PP
-The \fBncurses\fP library searches for terminal descriptions in several places.
-It uses only the first description found.
-The library has a compiled-in list of places to search
+The library uses a compiled-in list of pathnames,
which can be overridden by environment variables.
Before starting to search,
-\fBncurses\fP eliminates duplicates in its search list.
+\fBncurses\fP checks the search list,
+eliminating duplicates and pathnames where no terminal database is found.
+The \fBncurses\fP library reads the first description
+which passes its consistency checks.
.bP
-If the environment variable TERMINFO is set, it is interpreted as the pathname
-of a directory containing the compiled description you are working on.
-Only that directory is searched.
+The environment variable \fBTERMINFO\fR is checked first, for
+a terminal database containing the terminal description.
.bP
-If TERMINFO is not set,
-\fBncurses\fP will instead look in the directory \fB$HOME/.terminfo\fP
+Next,
+\fBncurses\fP looks in \fB$HOME/.terminfo\fP
for a compiled description.
+.IP
+This is an optional feature which may be omitted entirely from
+the library, or limited to prevent accidental use by privileged applications.
.bP
-Next, if the environment variable TERMINFO_DIRS is set,
-\fBncurses\fP will interpret the contents of that variable
-as a list of colon-separated directories (or database files) to be searched.
+Next, if the environment variable \fBTERMINFO_DIRS\fR is set,
+\fBncurses\fP interprets the contents of that variable
+as a list of colon-separated pathnames of terminal databases to be searched.
.IP
-An empty directory name (i.e., if the variable begins or ends
+An empty pathname (i.e., if the variable begins or ends
with a colon, or contains adjacent colons)
is interpreted as the system location \fI\*d\fP.
.bP
.bP
a list of directories (@TERMINFO_DIRS@), and
.bP
-the system terminfo directory, \fI\*d\fP (the compiled-in default).
+the system terminfo directory, \fI\*d\fP
.RE
-.SS Preparing Descriptions
.PP
+The \fBTERMINFO\fP variable can contain a terminal description instead
+of the pathname of a terminal database.
+If this variable begins with \*(``hex:\*('' or \*(``b64:\*(''
+then \fBncurses\fP 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
+\fB@TIC@\fR or \fB@INFOCMP@\fR.
+.PP
+The preceding addresses the usual configuration of \fBncurses\fP,
+which uses terminal descriptions prepared in \fIterminfo\fP format.
+While \fItermcap\fP is less expressive,
+\fBncurses\fP can also be configured to read \fItermcap\fP descriptions.
+In that configuration, it checks the \fBTERMCAP\fP and \fBTERMPATH\fP
+variables (for content and search path, respectively)
+after the system terminal database.
+.SS 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
key several times quickly.
If the terminal messes up, more padding is usually needed.
A similar test can be used for insert character.
-.PP
.SS Basic Capabilities
-.PP
The number of columns on each line for the terminal is given by the
\fBcols\fP numeric capability.
If the terminal is a \s-1CRT\s0, then the
.B nel
out of one or both of them.
.PP
-These capabilities suffice to describe hard-copy and \*(``glass-tty\*('' terminals.
+These capabilities suffice to describe
+hard-copy and \*(``glass-tty\*('' terminals.
Thus the model 33 teletype is described as
.PP
.DT
.nf
-.ft CW
+.ft \*(CW
.\".in -2
\s-133\||\|tty33\||\|tty\||\|model 33 teletype,
bel=^G, cols#72, cr=^M, cud1=^J, hc, ind=^J, os,\s+1
.PP
.DT
.nf
-.ft CW
+.ft \*(CW
.\".in -2
\s-1adm3\||\|3\||\|lsi adm3,
am, bel=^G, clear=^Z, cols#80, cr=^M, cub1=^H, cud1=^J,
.\".in +2
.ft R
.fi
-.PP
.SS Parameterized Strings
-.PP
Cursor addressing and other strings requiring parameters
in the terminal are described by a
parameterized string capability,
e.g., in the \fBsgr\fP string.
.PP
The \fB%\fP encodings have the following meanings:
-.PP
.TP 5
\fB%%\fP
outputs \*(``%\*(''
.TP
-\fB%\fP\fI[[\fP:\fI]flags][width[.precision]][\fP\fBdoxXs\fP\fI]\fP
+\fB%\fI[[\fR:\fI]flags][width[.precision]][\fBdoxXs\fI]\fR
as in \fBprintf\fP(3), flags are \fI[\-+#]\fP and \fIspace\fP.
Use a \*(``:\*('' to allow the next character to be a \*(``\-\*('' flag,
avoiding interpreting \*(``%\-\*('' as an operator.
.TP
-\f(CW%c\fP
+\f\*(CW%c\fP
print \fIpop()\fP like %c in \fBprintf\fP
.TP
\fB%s\fP
print \fIpop()\fP like %s in \fBprintf\fP
.TP
-\fB%p\fP\fI[1\-9]\fP
+\fB%p\fI[1\-9]\fR
push \fIi\fP'th parameter
.TP
-\fB%P\fP\fI[a\-z]\fP
+\fB%P\fI[a\-z]\fR
set dynamic variable \fI[a\-z]\fP to \fIpop()\fP
.TP
-\fB%g\fP\fI[a\-z]\fP
+\fB%g\fI[a\-z]\fR
get dynamic variable \fI[a\-z]\fP and push it
.TP
-\fB%P\fP\fI[A\-Z]\fP
+\fB%P\fI[A\-Z]\fR
set static variable \fI[a\-z]\fP to \fIpop()\fP
.TP
-\fB%g\fP\fI[A\-Z]\fP
+\fB%g\fI[A\-Z]\fR
get static variable \fI[a\-z]\fP and push it
.IP
The terms \*(``static\*('' and \*(``dynamic\*('' are misleading.
variables in the same manner as SVr4.
.RS
.bP
-Unlike other implementations, ncurses zeros dynamic variables
+Unlike other implementations, ncurses zeros dynamic variables
before the first \fB%g\fP or \fB%P\fP operator.
.bP
Like SVr2,
.RE
.RE
.TP
-\fB%\(aq\fP\fIc\fP\fB\(aq\fP
+\fB%\(aq\fIc\fB\(aq\fR
char constant \fIc\fP
.TP
-\fB%{\fP\fInn\fP\fB}\fP
+\fB%{\fInn\fB}\fR
integer constant \fInn\fP
.TP
\fB%l\fP
.PP
Consider the HP2645, which, to get to row 3 and column 12, needs
to be sent \eE&a12c03Y padded for 6 milliseconds.
-Note that the order
-of the rows and columns is inverted here, and that the row and column
-are printed as two digits.
-Thus its \fBcup\fP capability is \*(``cup=6\eE&%p2%2dc%p1%2dY\*(''.
+The order of the rows and columns is inverted here,
+and the row and column are printed as two digits.
+The corresponding terminal description is expressed thus:
+.RS
+cup=\eE&a%p2%dc%p1%dY$<6>,
+.RE
.PP
The Microterm \s-1ACT-IV\s0 needs the current row and column sent
preceded by a \fB^T\fP, with the row and column simply encoded in binary,
-\*(``cup=^T%p1%c%p2%c\*(''.
+.RS
+cup=^T%p1%c%p2%c
+.RE
+.PP
Terminals which use \*(``%c\*('' need to be able to
backspace the cursor (\fBcub1\fP),
and to move the cursor up one line on the screen (\fBcuu1\fP).
This turns out to be essential for the Ann Arbor 4080.)
.PP
A final example is the \s-1LSI ADM\s0-3a, which uses row and column
-offset by a blank character, thus \*(``cup=\eE=%p1%\(aq \(aq%+%c%p2%\(aq \(aq%+%c\*(''.
+offset by a blank character, thus
+.RS
+cup=\eE=%p1%\(aq \(aq%+%c%p2%\(aq \(aq%+%c
+.RE
+.PP
After sending \*(``\eE=\*('', 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.
-.PP
.SS Cursor Motions
-.PP
If the terminal has a fast way to home the cursor
(to very upper left corner of screen) then this can be given as
\fBhome\fP; similarly a fast way of getting to the lower left-hand corner
.PP
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 \fBsmcup\fP and \fBrmcup\fP.
+the codes to enter and exit this mode can be given
+as \fBsmcup\fP and \fBrmcup\fP.
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
If the \fBsmcup\fP sequence will not restore the screen after an
\fBrmcup\fP sequence is output (to the state prior to outputting
\fBrmcup\fP), specify \fBnrrmc\fP.
-.PP
.SS Margins
SVr4 (and X/Open Curses)
list several string capabilities for setting margins.
parameterized capabilities for setting the top, bottom, left, right margins
given the number of rows or columns.
.RE
-.RE
.PP
In practice, the categorization into \*(``terminal\*('' and \*(``printer\*(''
is not suitable:
right edge of the display (rather than leaving the margin unmodified).
.PP
These are the margin-related capabilities:
+.PP
.TS
center;
-l l
-_ _
-lw8 lw18.
-\fBName Description\fP
+lb lb
+lb l .
+Name Description
+_
smgl Set left margin at current column
smgr Set right margin at current column
smgb Set bottom margin at current line
both arguments must be given.
.PP
Conversely, when only one capability in the pair is set:
-.bP
+.bP
If only one of \fBsmglp\fP and \fBsmgrp\fP is set,
then it is used with two arguments,
the column number of the left and right margins, in that order.
Applications such as \fBtabs\fP(1) rely upon this to reset all margins.
.\"
.SS Area Clears
-.PP
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 \fBel\fP.
If the terminal can clear from the beginning of the line to the current
if a true
.B ed
is not available.)
-.PP
.\"
.SS Insert/delete line and vertical motions
-.PP
If the terminal can open a new blank line before the line where the cursor
is, this should be given as \fBil1\fP; this is done only from the first
position of a line.
These indicate
that deleting a line or scrolling may bring non-blank lines up from below
or that scrolling back with \fBri\fP may bring down non-blank lines.
-.PP
.SS Insert/Delete Character
-.PP
There are two basic kinds of intelligent terminals with respect to
insert/delete character which can be described using
.I terminfo.
can be given as
.B ech
with one parameter.
-.PP
.SS "Highlighting, Underlining, and Visible Bells"
-.PP
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
.B sgr
(set attributes),
taking 9 parameters.
-Each parameter is either 0 or nonzero, as the corresponding attribute is on or off.
+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.
.PP
.TS
center;
-l l l
-l l l
-lw18 lw14 lw18.
-\fBtparm parameter attribute escape sequence\fP
-
-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
+lb lb lb
+l l l .
+tparm Parameter Attribute Escape Sequence
+_
+none none \eE[0m
+p1 standout \eE[0;1;7m
+p2 underline \eE[0;4m
+p3 reverse \eE[0;7m
+p4 blink \eE[0;5m
p5 dim not available
-p6 bold \\E[0;1m
-p7 invis \\E[0;8m
+p6 bold \eE[0;1m
+p7 invis \eE[0;8m
p8 protect not used
p9 altcharset ^O (off) ^N (on)
.TE
.ne 11
.TS
center;
-l l l
-l l l
-lw18 lw14 lw18.
-\fBsequence when to output terminfo translation\fP
-
-.ft CW
+lb lb lb
+l l l .
+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%;
;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%;
-.ft R
+\*^N or \*^O if p9 \*^N, else \*^O %?%p9%t\*^N%e\*^O%;
.TE
.PP
Putting this all together into the sgr sequence gives:
.PP
-.ft CW
+.ft \*(CW
.nf
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%;,
specify the capability \fBos\fP.
If overstrikes are erasable with a blank,
then this should be indicated by giving \fBeo\fP.
-.PP
.SS Keypad and Function Keys
-.PP
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
give them in \fBsmln\fP and \fBrmln\fP.
\fBsmln\fP is normally output after one or more pln
sequences to make sure that the change becomes visible.
-.PP
.SS Tabs and Initialization
-.PP
A few capabilities are used only for tabs:
.bP
If the terminal has hardware tabs, the command to advance to the next
only when the \fBit\fP (\fBinit_tabs\fP) capability
is set to a value other than \fIeight\fP.
.SS Delays and Padding
-.PP
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).
Only the first character of the
.B pad
string is used.
-.PP
.SS Status Lines
Some terminals have an extra \*(``status line\*('' which is not normally used by
software (and thus not counted in the terminal's \fBlines\fP capability).
.PP
The \fBncurses\fP implementation does not yet use any of these capabilities.
They are documented here in case they ever become important.
-.PP
.SS Line Graphics
-.PP
Many terminals have alternate character sets useful for forms-drawing.
Terminfo and \fBcurses\fP 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 \fBacsc\fP capability.
.PP
-.TS H
-center expand;
-l l l l l
-l l l l l
-_ _ _ _ _
-lw25 lw10 lw6 lw6 lw6.
-.\".TH
-\fBGlyph ACS Ascii acsc acsc\fP
-\fBName Name Default Char Value\fP
+.TS
+center;
+lb lb lb lb lb.
+\& \& ASCII acsc acsc
+Glyph Name ACS Name Fallback Symbol Value
+_
+.T&
+l lb l l l .
arrow pointing right ACS_RARROW > + 0x2b
arrow pointing left ACS_LARROW < , 0x2c
-arrow pointing up ACS_UARROW ^ \- 0x2d
+arrow pointing up ACS_UARROW \*^ \- 0x2d
arrow pointing down ACS_DARROW v . 0x2e
solid square block ACS_BLOCK # 0 0x30
diamond ACS_DIAMOND + ` 0x60
upper left corner ACS_ULCORNER + l 0x6c
lower left corner ACS_LLCORNER + m 0x6d
large plus or crossover ACS_PLUS + n 0x6e
-scan line 1 ACS_S1 ~ o 0x6f
+scan line 1 ACS_S1 \*~ o 0x6f
scan line 3 ACS_S3 \- p 0x70
horizontal line ACS_HLINE \- q 0x71
scan line 7 ACS_S7 \- r 0x72
greek pi ACS_PI * { 0x7b
not-equal ACS_NEQUAL ! | 0x7c
UK pound sign ACS_STERLING f } 0x7d
-bullet ACS_BULLET o ~ 0x7e
+bullet ACS_BULLET o \*~ 0x7e
.TE
.PP
A few notes apply to the table itself:
as the corresponding graphic.
Then read off the VT100/your terminal
character pairs right to left in sequence; these become the ACSC string.
-.PP
.SS Color Handling
-.PP
The curses library functions \fBinit_pair\fP and \fBinit_color\fP
manipulate the \fIcolor pairs\fP and \fIcolor values\fP discussed in this
section
map these as it likes, but the RGB values indicate normal locations in color
space.
.PP
-.TS H
+.TS
center;
-l c c c
-l l n l.
-\fBColor #define Value RGB\fP
-black \fBCOLOR_BLACK\fP 0 0, 0, 0
-red \fBCOLOR_RED\ \fP 1 max,0,0
-green \fBCOLOR_GREEN\fP 2 0,max,0
-yellow \fBCOLOR_YELLOW\fP 3 max,max,0
-blue \fBCOLOR_BLUE\fP 4 0,0,max
-magenta \fBCOLOR_MAGENTA\fP 5 max,0,max
-cyan \fBCOLOR_CYAN\fP 6 0,max,max
-white \fBCOLOR_WHITE\fP 7 max,max,max
+cb cb cb cb s s
+l lb c l1 l1 l .
+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
.TE
.PP
The argument values of \fBsetf\fP/\fBsetb\fP historically correspond to
a different mapping, i.e.,
-.TS H
+.PP
+.TS
center;
-l c c c
-l l n l.
-\fBColor #define Value RGB\fP
-black \fBCOLOR_BLACK\fP 0 0, 0, 0
-blue \fBCOLOR_BLUE\fP 1 0,0,max
-green \fBCOLOR_GREEN\fP 2 0,max,0
-cyan \fBCOLOR_CYAN\fP 3 0,max,max
-red \fBCOLOR_RED\ \fP 4 max,0,0
-magenta \fBCOLOR_MAGENTA\fP 5 max,0,max
-yellow \fBCOLOR_YELLOW\fP 6 max,max,0
-white \fBCOLOR_WHITE\fP 7 max,max,max
+cb cb cb cb s s
+l lb c l1 l1 l .
+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
.TE
.PP
It is important to not confuse the two sets of color capabilities;
.PP
.TS
center;
-l l l l
-lw20 lw2 lw10 lw10.
-\fBAttribute Bit Decimal Set by\fP
+cb cb cb cb
+lb n n lb.
+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_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
.PP
SVr4 curses does nothing with \fBncv\fP, ncurses recognizes it and optimizes
the output in favor of colors.
-.PP
.SS Miscellaneous
If the terminal requires other than a null (zero) character as a pad, then this
can be given as pad.
is the number of times to repeat it.
Thus, tparm(repeat_char, \(aqx\(aq, 10) is the same as \*(``xxxxxxxxxx\*(''.
.PP
-If the terminal has a settable command character, such as the \s-1TEKTRONIX\s+1 4025,
+If the terminal has a settable command character,
+such as the \s-1TEKTRONIX\s+1 4025,
this can be indicated with
.BR cmdch .
A prototype command character is chosen which is used in all capabilities.
is transparently passed to the printer while an
.B mc5p
is in effect.
-.PP
.SS Glitches and Braindamage
-.PP
-Hazeltine terminals, which do not allow \*(``~\*('' characters to be displayed should
+Hazeltine terminals,
+which do not allow \*(``~\*('' characters to be displayed should
indicate \fBhz\fP.
.PP
Terminals which ignore a line-feed immediately after an \fBam\fP wrap,
\*(``beehive_glitch\*(''; it is now \*(``no_esc_ctl_c\*(''.
.PP
Other specific terminal problems may be corrected by adding more
-capabilities of the form \fBx\fP\fIx\fP.
-.PP
+capabilities of the form \fBx\fIx\fR.
.SS Pitfalls of Long Entries
-.PP
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.
+translations are much more strictly limited (to 1023 bytes),
+thus termcap translations of long terminfo entries can cause problems.
.PP
-The man pages for 4.3BSD and older versions of \fBtgetent\fP instruct the user to
+The man pages for 4.3BSD
+and older versions of \fBtgetent\fP 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 \fBtgetent\fP
-is searching for is, several bad things can happen.
+Depending on what the application and the termcap library being used does,
+and where in the termcap file the terminal type that \fBtgetent\fP
+is searching for is, several bad things can happen:
+.bP
+some termcap libraries print a warning message,
+.bP
+some exit if they find an entry that's longer than 1023 bytes,
+.bP
+some neither exit nor warn, doing nothing useful, and
+.bP
+some simply truncate the entries to 1023 bytes.
.PP
-Some termcap libraries print a warning message or exit if they find an
-entry that's longer than 1023 bytes; others do not; others truncate the
-entries to 1023 bytes.
Some application programs allocate more than
the recommended 1K for the termcap entry; others do not.
.PP
does not appear in the file at all (so that \fBtgetent\fP has to search
the whole termcap file).
.PP
-Then \fBtgetent\fP will overwrite memory, perhaps its stack, and probably core dump
-the program.
+Then \fBtgetent\fP 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
SVr1, and have added extension capabilities to the string table that (in the
binary format) collide with System V and XSI Curses extensions.
.SH EXTENSIONS
-.PP
Searching for terminal descriptions in
\fB$HOME/.terminfo\fP and TERMINFO_DIRS
is not supported by older implementations.
X/Open Curses does not mention italics.
Portable applications must assume that numeric capabilities are
signed 16-bit values.
-This includes the \fIno_color_video\fP (ncv) capability.
-The 32768 mask value used for italics with ncv can be confused with
-an absent or cancelled ncv.
+This includes the \fIno_color_video\fP (\fBncv\fP) capability.
+The 32768 mask value used for italics with \fBncv\fP can be confused with
+an absent or cancelled \fBncv\fP.
If italics should work with colors,
-then the ncv value must be specified, even if it is zero.
+then the \fBncv\fP value must be specified, even if it is zero.
.PP
Different commercial ports of terminfo and curses support different subsets of
the XSI Curses standard and (in some cases) different extension sets.
.TP 25
\*d/?/*
files containing terminal descriptions
+.SH AUTHORS
+Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey.
+Based on \fIpcurses\fP by Pavel Curtis.
.SH SEE ALSO
+.na
+.hy 0
\fB@INFOCMP@\fP(1M),
\fB@TABS@\fP(1),
\fB@TIC@\fP(1M),
\fBterm_variables\fP(3X).
\fBterm\fP(\*n).
\fBuser_caps\fP(5).
-.SH AUTHORS
-Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey.
-Based on \fIpcurses\fP by Pavel Curtis.