+'\" t
.\"***************************************************************************
.\" Copyright 2018-2021,2023 Thomas E. Dickey *
.\" Copyright 1998-2016,2017 Free Software Foundation, Inc. *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: term.5,v 1.60 2023/10/14 19:18:14 tom Exp $
-.TH term 5 2023-10-14 "ncurses 6.4" "File formats"
+.\" $Id: term.5,v 1.67 2023/12/02 20:49:04 tom Exp $
+.TH term 5 2023-12-02 "ncurses 6.4" "File formats"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
.ds ' '
.ds ^ ^
.\}
+.ie n .ds CW R
+.el \{
+.ie \n(.g .ds CW CR
+.el .ds CW CW
+.\}
.
.de bP
.ie n .IP \(bu 4
.el .IP \(bu 2
..
.
-.ds n 5
.ds d @TERMINFO@
.SH NAME
term \-
.TP 5
.B directory tree
A two-level scheme is used to avoid a linear search
-of a huge \s-1UNIX\s+1 system directory: \fB\*d/c/name\fP where
+of a huge Unix system directory: \fB\*d/c/name\fP where
.I name
is the name of the terminal, and
.I c
but cannot write entries into the directory tree.
It can write (or rewrite) entries in the hashed database.
.IP
-\fBncurses\fP distinguishes the two cases in the TERMINFO and TERMINFO_DIRS
-environment variable by assuming a directory tree for entries that
-correspond to an existing directory,
+\fBncurses\fP distinguishes the two cases in the \fI\%TERMINFO\fP and
+\fI\%TERMINFO_DIRS\fP environment variable by assuming a directory tree
+for entries that correspond to an existing directory,
and hashed database otherwise.
.SS LEGACY STORAGE FORMAT
The format has been chosen so that it will be the same on all hardware.
.SS EXTENDED STORAGE FORMAT
The previous section describes the conventional terminfo binary format.
With some minor variations of the offsets (see PORTABILITY),
-the same binary format is used in all modern UNIX systems.
+the same binary format is used in all modern Unix systems.
Each system uses a predefined set of boolean, number or string capabilities.
.PP
The \fBncurses\fP libraries and applications support
the extended capabilities in order, e.g., booleans, then numbers and
finally strings.
.PP
+By storing terminal descriptions in this way,
+\fBncurses\fP is able to provide a database useful with legacy applications,
+as well as providing data for applications which need more than the
+predefined capabilities.
+See \fBuser_caps\fP(5) for an overview
+of the way \fBncurses\fP uses this extended information.
+.PP
Applications which manipulate terminal data can use the definitions
described in \fBterm_variables\fP(3X) which associate the long capability
names with members of a \fBTERMTYPE\fP structure.
However, that cannot provide callers with the extended numbers.
The library uses a similar but hidden data structure \fBTERMTYPE2\fP
to provide data for the terminfo functions.
+.SH FILES
+.TP
+.I \*d
+compiled terminal description database
.SH PORTABILITY
.SS setupterm
Note that it is possible for
of boolean, number, and string capabilities.
.SS Binary format
X/Open Curses does not specify a format for the terminfo database.
-UNIX System V curses used a directory-tree of binary files,
+System V curses used a directory-tree of binary files,
one per terminal description.
.PP
Despite the consistent use of little-endian for numbers and the otherwise
self-describing format, it is not wise to count on portability of binary
-terminfo entries between commercial UNIX versions.
+terminfo entries between commercial Unix versions.
The problem is that there
are at least three versions of terminfo (under HP\-UX, AIX, and OSF/1) which
diverged from System V terminfo after SVr1, and have added extension
capabilities to the string table that (in the binary format) collide with
System V and XSI Curses extensions.
-See \fBterminfo\fP(\*n) for detailed
+See \fBterminfo\fP(5) for detailed
discussion of terminfo source compatibility issues.
.PP
This implementation is by default compatible with the binary
\fBncurses\fP represents the \*(``first character\*(''
of the terminal name used as
the intermediate level of a directory tree in (two-character) hexadecimal form.
-.SH EXAMPLE
+.SS Limits
+\fBncurses\fP stores compiled terminal descriptions
+in three related formats,
+described in the sections
+.bP
+\fBLEGACY STORAGE FORMAT\fP, and
+.bP
+\fBEXTENDED STORAGE FORMAT\fP, and
+.bP
+\fBEXTENDED NUMBER FORMAT\fP.
+.PP
+The legacy storage format and the extended number format differ by
+the types of numeric capability which they can store
+(i.e., 16-bit versus 32-bit integers).
+The extended storage format introduced by ncurses 5.0 adds data to
+either of these formats.
+.PP
+Some limitations apply:
+.bP
+total compiled entries cannot exceed 4096 bytes in the legacy format.
+.bP
+total compiled entries cannot exceed 32768 bytes in the extended format.
+.bP
+the name field cannot exceed 128 bytes.
+.PP
+Compiled entries are limited to 32768 bytes because offsets into the
+\fIstrings table\fP use two-byte integers.
+The legacy format could have supported 32768-byte entries,
+but was limited to a virtual memory page's 4096 bytes.
+.SH EXAMPLES
As an example, here is a description for the Lear-Siegler
ADM\-3, a popular though rather stupid early terminal:
.PP
0150 00 08 00 0c 00 0b 00 0a 00 ........ .
.TE
.in
-.SH LIMITS
-Some limitations:
-.bP
-total compiled entries cannot exceed 4096 bytes in the legacy format.
-.bP
-total compiled entries cannot exceed 32768 bytes in the extended format.
-.bP
-the name field cannot exceed 128 bytes.
-.PP
-Compiled entries are limited to 32768 bytes because offsets into the
-\fIstrings table\fP use two-byte integers.
-The legacy format could have supported 32768-byte entries,
-but was limited a virtual memory page's 4096 bytes.
-.SH FILES
-.TP
-.I \*d
-compiled terminal description database
.SH AUTHORS
Thomas E. Dickey
.br
.SH SEE ALSO
\fB\%curses\fP(3X),
\fB\%curs_terminfo\fP(3X),
-\fB\%terminfo\fP(\*n)
+\fB\%terminfo\fP(5),
+\fB\%user_caps\fP(5)
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