Compiled terminfo descriptions are placed under the directory
- /usr/local/ncurses/lib/terminfo. Two configurations are supported
- (when building the ncurses libraries):
+ /usr/share/terminfo. Two configurations are supported (when building
+ the ncurses libraries):
directorytree
A two-level scheme is used to avoid a linear search of a huge UNIX
- system directory: /usr/local/ncurses/lib/terminfo/c/name where
- name is the name of the terminal, and c is the first character of
- name. Thus, act4 can be found in the file
- /usr/local/ncurses/lib/terminfo/a/act4. Synonyms for the same
- terminal are implemented by multiple links to the same compiled
- file.
+ system directory: /usr/share/terminfo/c/name where name is the
+ name of the terminal, and c is the first character of name. Thus,
+ act4 can be found in the file /usr/share/terminfo/a/act4.
+ Synonyms for the same terminal are implemented by multiple links
+ to the same compiled file.
hasheddatabase
- Using Berkeley database, two types of records are stored: the ter-
- minfo data in the same format as stored in a directory tree with
- 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-
- minfo databases organized as a directory tree, but cannot write
- entries into the directory tree. It can write (or rewrite)
+ Using Berkeley database, two types of records are stored: the
+ terminfo data in the same format as stored in a directory tree
+ with 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
+ terminfo 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-
- MINFO_DIRS environment variable by assuming a directory tree for
- entries that correspond to an existing directory, and hashed data-
- base otherwise.
+ ncurses 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, and hashed
+ database otherwise.
The format has been chosen so that it will be the same on all hardware.
- An 8 or more bit byte is assumed, but no assumptions about byte order-
- ing or sign extension are made.
+ An 8 or more bit byte is assumed, but no assumptions about byte
+ ordering 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.
+ The compiled file is created with the tic program, and read by the
+ routine 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;
+
+ (3) the number of bytes in the booleanflags section;
+
+ (4) the number of short integers in the numbers section;
+
+ (5) the number of offsets (short integers) in the strings section;
- (2) the size, in bytes, of the names section;
+ (6) the size, in bytes, of the stringtable.
- (3) the number of bytes in the boolean section;
+ The capabilities in the booleanflags, numbers, and strings sections
+ are in the same order as the file <term.h>.
- (4) the number of short integers in the numbers section;
+ Short integers are signed, in the range -32768 to 32767. They are
+ stored as 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*second+first.)
+ This format corresponds to the hardware of the VAX and PDP-11 (that is,
+ little-endian machines). Machines where this does not correspond to
+ the hardware must read the integers as two bytes and compute the
+ little-endian value.
- (5) the number of offsets (short integers) in the strings section;
+ Numbers in a terminal description, whether they are entries in the
+ numbers 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:
- (6) the size, in bytes, of the string table.
+ o If a capability is absent from this terminal, tic stores a -1 in
+ the corresponding table.
- 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
- 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 integer value -1 is represented by two bytes 0377, 0377.
+ Absent boolean values are represented by the byte 0 (false).
- 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.
+ o If a capability has been canceled from this terminal, tic stores a
+ -2 in the corresponding table.
- 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 integer value -2 is represented by two bytes 0377, 0376.
+ The boolean value -2 is represented by the byte 0376.
- 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.
+ o Other negative values are illegal.
- 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 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
+ section is terminated with an ASCII NUL character.
- 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 booleanflags section has one byte for each flag. Boolean
+ capabilities are either 1 or 0 (true or false) according to whether the
+ terminal supports the given capability or not.
- 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.
+ 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 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. The capability value is an index into the stringtable.
+
+ 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.
@@ -160,13 +191,13 @@
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-
- 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
- according to its own scheme.
+ The ncurses libraries and applications support extended terminfo binary
+ format, allowing users to define capabilities which are loaded at
+ runtime. 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 according to its own scheme.
First, it reads the extended header (5 short integers):
@@ -176,121 +207,162 @@
(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.
- After the end of these values, it contains the names for each of the
- extended capabilities in order, e.g., booleans, then numbers and
+ The extended string table contains values for string capabilities.
+ After the end of these values, it contains the names for each of the
+ extended capabilities in order, e.g., booleans, then numbers and
finally strings.
- Applications which manipulate terminal data can use the definitions
- described in term_variables(3x) which associate the long capability
+ Applications which manipulate terminal data can use the definitions
+ described in term_variables(3x) which associate the long capability
names with members of a TERMTYPE structure.
- 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
+ o changing the type for the number array from signed 16-bit integers
to signed 32-bit integers.
- To maintain compatibility, the library presents the same data struc-
- tures to direct users of the TERMTYPE structure as in previous formats.
- However, that cannot provide callers with the extended numbers. The
- library uses a similar but hidden data structure TERMTYPE2 to provide
- data for the terminfo functions.
+ To maintain compatibility, the library presents the same data
+ structures to direct users of the TERMTYPE structure as in previous
+ formats. However, that cannot provide callers with the extended
+ numbers. The library uses a similar but hidden data structure
+ TERMTYPE2 to provide data for the terminfo functions.
- 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-
- ing in extra unrecognized entries in the file) or the program may have
- been recompiled more recently than the database was updated (resulting
- in missing entries). The routine setupterm must be prepared for both
- possibilities - this is why the numbers and sizes are included. Also,
- new capabilities must always be added at the end of the lists of bool-
- ean, number, and string capabilities.
-
- 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
- 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
- terminfo(5) for detailed discussion of terminfo source compatibility
- issues.
-
- 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.
+
+
+ Note that it is possible for setupterm to expect a different set of
+ capabilities than are actually present in the file. Either the
+ database may have been updated since setupterm has been recompiled
+ (resulting in extra unrecognized entries in the file) or the program
+ may have been recompiled more recently than the database was updated
+ (resulting in missing entries). The routine setupterm must be prepared
+ for both possibilities - this is why the numbers and sizes are
+ included. Also, new capabilities must always be added at the end of
+ the lists of boolean, 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
+ otherwise self-describing format, it is not wise to count on
+ portability of binary 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 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
+ applications. Portable applications should use the tigetflag and
+ related functions described in curs_terminfo(3x) for reading terminal
+ capabilities.
+
+
+
+ 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
+ character" of the terminal name used as the intermediate level of a
+ directory tree in (two-character) hexadecimal form.
Some limitations:
- o total compiled entries cannot exceed 4096 bytes in the legacy for-
- mat.
+ o total compiled entries cannot exceed 4096 bytes in the legacy
+ format.
- o total compiled entries cannot exceed 32768 bytes in the extended
+ o total compiled entries cannot exceed 32768 bytes in the extended
format.
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
+ supported 32768-byte entries, but was limited a virtual memory page's
+ 4096 bytes.
+
@@ -304,7 +376,7 @@
extended number support for ncurses 6.1
Eric S. Raymond
- documented legacy terminfo format, e.g., from pdcurses.
+ documented legacy terminfo format, e.g., from pcurses.
@@ -322,7 +394,15 @@