Compiled terminfo descriptions are placed under the directory
/usr/share/terminfo. Two configurations are supported (when building
- the ncurses libraries):
+ the ncurses libraries):
directorytree
A two-level scheme is used to avoid a linear search of a huge UNIX
@@ -74,12 +75,12 @@
the terminfo's primary name as a key, and records containing only
aliases pointing to the primary name.
- If built to write hashed databases, ncurses can still read ter-
+ If built to write hashed databases, ncurses can still read ter-
minfo databases organized as a directory tree, but cannot write
entries into the directory tree. It can write (or rewrite)
entries in the hashed database.
- ncurses distinguishes the two cases in the TERMINFO and TER-
+ ncurses distinguishes the two cases in the TERMINFO and TER-
MINFO_DIRS environment variable by assuming a directory tree for
entries that correspond to an existing directory, and hashed data-
base otherwise.
@@ -91,80 +92,111 @@
ing or sign extension are made.
The compiled file is created with the tic program, and read by the rou-
- tine setupterm(3x). The file is divided into six parts: the header,
- terminal names, boolean flags, numbers, strings, and string table.
+ tine setupterm(3x). The file is divided into six parts:
- The header section begins the file. This section contains six short
+ a) header,
+
+ b) terminalnames,
+
+ c) booleanflags,
+
+ d) numbers,
+
+ e) strings, and
+
+ f) stringtable.
+
+ The header section begins the file. This section contains six short
integers in the format described below. These integers are
- (1) the magic number (octal 0432);
+ (1) the magicnumber (octal 0432);
+
+ (2) the size, in bytes, of the terminalnames section;
- (2) the size, in bytes, of the names section;
+ (3) the number of bytes in the booleanflags section;
- (3) the number of bytes in the boolean section;
+ (4) the number of short integers in the numbers section;
- (4) the number of short integers in the numbers section;
+ (5) the number of offsets (short integers) in the strings section;
- (5) the number of offsets (short integers) in the strings section;
+ (6) the size, in bytes, of the stringtable.
- (6) the size, in bytes, of the string table.
+ The capabilities in the booleanflags, numbers, and strings sections
+ are in the same order as the file <term.h>.
- Short integers are stored in two 8-bit bytes. The first byte contains
- the least significant 8 bits of the value, and the second byte contains
- the most significant 8 bits. (Thus, the value represented is 256*sec-
- ond+first.) The value -1 is represented by the two bytes 0377, 0377;
- other negative values are illegal. This value generally means that the
- corresponding capability is missing from this terminal. Note that this
+ Short integers are signed, in the range -32768 to 32767. They are
+ stored as two 8-bit bytes. The first byte contains the least signifi-
+ cant 8 bits of the value, and the second byte contains the most signif-
+ icant 8 bits. (Thus, the value represented is 256*second+first.) This
format corresponds to the hardware of the VAX and PDP-11 (that is, lit-
tle-endian machines). Machines where this does not correspond to the
hardware must read the integers as two bytes and compute the little-
endian value.
- The terminal names section comes next. It contains the first line of
- the terminfo description, listing the various names for the terminal,
- separated by the "|" character. The section is terminated with an
- ASCII NUL character.
+ Numbers in a terminal description, whether they are entries in the num-
+ bers or strings table, are positive integers. Boolean flags are
+ treated as positive one-byte integers. In each case, those positive
+ integers represent a terminal capability. The terminal compiler tic
+ uses negative integers to handle the cases where a capability is not
+ available:
+
+ o If a capability is absent from this terminal, tic stores a -1 in
+ the corresponding table.
+
+ The integer value -1 is represented by two bytes 0377, 0377.
+ Absent boolean values are represented by the byte 0 (false).
+
+ o If a capability has been canceled from this terminal, tic stores a
+ -2 in the corresponding table.
+
+ The integer value -2 is represented by two bytes 0377, 0376.
+ The boolean value -2 is represented by the byte 0376.
+
+ o Other negative values are illegal.
+
+ The terminalnames section comes after the header. It contains the
+ first line of the terminfo description, listing the various names for
+ the terminal, separated by the "|" character. The terminalnames sec-
+ tion is terminated with an ASCII NUL character.
- The boolean flags have one byte for each flag. This byte is either 0
- or 1 as the flag is present or absent. The capabilities are in the
- same order as the file <term.h>.
+ The booleanflags section has one byte for each flag. Boolean capabil-
+ ities are either 1 or 0 (true or false) according to whether the termi-
+ nal supports the given capability or not.
- Between the boolean section and the number section, a null byte will be
- inserted, if necessary, to ensure that the number section begins on an
- even byte (this is a relic of the PDP-11's word-addressed architecture,
- originally designed in to avoid IOT traps induced by addressing a word
- on an odd byte boundary). All short integers are aligned on a short
- word boundary.
+ Between the booleanflags section and the number section, a null byte
+ will be inserted, if necessary, to ensure that the number section
+ begins on an even byte This is a relic of the PDP-11's word-addressed
+ architecture, originally designed to avoid traps induced by addressing
+ a word on an odd byte boundary. All short integers are aligned on a
+ short word boundary.
- The numbers section is similar to the flags section. Each capability
- takes up two bytes, and is stored as a little-endian short integer. If
- the value represented is -1, the capability is taken to be missing.
+ The numbers section is similar to the booleanflags section. Each
+ capability takes up two bytes, and is stored as a little-endian short
+ integer.
- The strings section is also similar. Each capability is stored as a
- short integer, in the format above. A value of -1 means the capability
- is missing. Otherwise, the value is taken as an offset from the begin-
- ning of the string table. Special characters in ^X or \c notation are
- stored in their interpreted form, not the printing representation.
- Padding information $<nn> and parameter information %x are stored
- intact in uninterpreted form.
+ The strings section is also similar. Each capability is stored as a
+ short integer. The capability value is an index into the stringtable.
- The final section is the string table. It contains all the values of
- string capabilities referenced in the string section. Each string is
- null terminated.
+ The stringtable is the last section. It contains all of the values of
+ string capabilities referenced in the strings section. Each string is
+ null-terminated. Special characters in ^X or \c notation are stored in
+ their interpreted form, not the printing representation. Padding
+ information $<nn> and parameter information %x are stored intact in
+ uninterpreted form.
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. Each system uses a
+ With some minor variations of the offsets (see PORTABILITY), the same
+ binary format is used in all modern UNIX systems. Each system uses a
predefined set of boolean, number or string capabilities.
- The ncurses libraries and applications support extended terminfo binary
- format, allowing users to define capabilities which are loaded at run-
+ The ncurses libraries and applications support extended terminfo binary
+ format, allowing users to define capabilities which are loaded at run-
time. This extension is made possible by using the fact that the other
- implementations stop reading the terminfo data when they have reached
- the end of the size given in the header. ncurses checks the size, and
- if it exceeds that due to the predefined data, continues to parse
+ implementations stop reading the terminfo data when they have reached
+ the end of the size given in the header. ncurses checks the size, and
+ if it exceeds that due to the predefined data, continues to parse
according to its own scheme.
First, it reads the extended header (5 short integers):
@@ -175,11 +207,14 @@
(3) count of extended string capabilities
- (4) size of the extended string table in bytes.
+ (4) count of the items in extended string table
- (5) last offset of the extended string table in bytes.
+ (5) size of the extended string table in bytes
- Using the counts and sizes, ncurses allocates arrays and reads data for
+ The count- and size-values for the extended string table include the
+ extended capability names as well as extended capability values.
+
+ Using the counts and sizes, ncurses allocates arrays and reads data for
the extended capabilities in the same order as the header information.
The extended string table contains values for string capabilities.
@@ -193,11 +228,11 @@
- On occasion, 16-bit signed integers are not large enough. With ncurses
- 6.1, a new format is introduced by making a few changes to the legacy
+ On occasion, 16-bit signed integers are not large enough. With ncurses
+ 6.1, a new format was introduced by making a few changes to the legacy
format:
- o a different magic number (0542)
+ o a different magic number (octal 01036)
o changing the type for the number array from signed 16-bit integers
to signed 32-bit integers.
@@ -210,6 +245,8 @@
Note that it is possible for setupterm to expect a different set of
capabilities than are actually present in the file. Either the data-
base may have been updated since setupterm has been recompiled (result-
@@ -220,6 +257,12 @@
new capabilities must always be added at the end of the lists of bool-
ean, number, and string capabilities.
+
+
+ X/Open Curses does not specify a format for the terminfo database.
+ UNIX System V curses used a directory-tree of binary files, one per
+ terminal description.
+
Despite the consistent use of little-endian for numbers and the other-
wise self-describing format, it is not wise to count on portability of
binary terminfo entries between commercial UNIX versions. The problem
@@ -230,14 +273,34 @@
terminfo(5) for detailed discussion of terminfo source compatibility
issues.
+ This implementation is by default compatible with the binary terminfo
+ format used by Solaris curses, except in a few less-used details where
+ it was found that the latter did not match X/Open Curses. The format
+ used by the other Unix versions can be matched by building ncurses with
+ different configuration options.
+
+
+
+ The magic number in a binary terminfo file is the first 16-bits (two
+ bytes). Besides making it more reliable for the library to check that
+ a file is terminfo, utilities such as file also use that to tell what
+ the file-format is. System V defined more than one magic number, with
+ 0433, 0435 as screen-dumps (see scr_dump(5)). This implementation uses
+ 01036 as a continuation of that sequence, but with a different high-
+ order byte to avoid confusion.
+
+
+
Direct access to the TERMTYPE structure is provided for legacy applica-
tions. Portable applications should use the tigetflag and related
functions described in curs_terminfo(3x) for reading terminal capabili-
ties.
+
+
A small number of terminal descriptions use uppercase characters in
their names. If the underlying filesystem ignores the difference
- between uppercase and lowercase, ncurses represents the "first charac-
+ between uppercase and lowercase, ncurses represents the "first charac-
ter" of the terminal name used as the intermediate level of a directory
tree in (two-character) hexadecimal form.
@@ -292,6 +355,11 @@
o the name field cannot exceed 128 bytes.
+ Compiled entries are limited to 32768 bytes because offsets into the
+ stringstable use two-byte integers. The legacy format could have sup-
+ ported 32768-byte entries, but was limited a virtual memory page's 4096
+ bytes.
+