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+ * Copyright 2018-2019,2020 Thomas E. Dickey *
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</PRE><H3><a name="h3-STORAGE-LOCATION">STORAGE LOCATION</a></H3><PRE>
Compiled terminfo descriptions are placed under the directory
<STRONG>/usr/share/terminfo</STRONG>. Two configurations are supported (when building
- the ncurses libraries):
+ the <STRONG>ncurses</STRONG> libraries):
<STRONG>directory</STRONG> <STRONG>tree</STRONG>
A two-level scheme is used to avoid a linear search of a huge UNIX
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, <STRONG>ncurses</STRONG> 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-
+ <STRONG>ncurses</STRONG> 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.
ing or sign extension are made.
The compiled file is created with the <STRONG>tic</STRONG> program, and read by the rou-
- tine <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>. The file is divided into six parts: the header,
- terminal names, boolean flags, numbers, strings, and string table.
+ tine <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>. The file is divided into six parts:
- The header section begins the file. This section contains six short
+ a) <EM>header</EM>,
+
+ b) <EM>terminal</EM> <EM>names</EM>,
+
+ c) <EM>boolean</EM> <EM>flags</EM>,
+
+ d) <EM>numbers</EM>,
+
+ e) <EM>strings</EM>, and
+
+ f) <EM>string</EM> <EM>table</EM>.
+
+ The <EM>header</EM> 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 <EM>magic</EM> <EM>number</EM> (octal 0432);
+
+ (2) the size, in bytes, of the <EM>terminal</EM> <EM>names</EM> section;
- (2) the size, in bytes, of the names section;
+ (3) the number of bytes in the <EM>boolean</EM> <EM>flags</EM> section;
- (3) the number of bytes in the boolean section;
+ (4) the number of short integers in the <EM>numbers</EM> section;
- (4) the number of short integers in the numbers section;
+ (5) the number of offsets (short integers) in the <EM>strings</EM> section;
- (5) the number of offsets (short integers) in the strings section;
+ (6) the size, in bytes, of the <EM>string</EM> <EM>table</EM>.
- (6) the size, in bytes, of the string table.
+ The capabilities in the <EM>boolean</EM> <EM>flags</EM>, <EM>numbers</EM>, and <EM>strings</EM> 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 <EM>num-</EM>
+ <EM>bers</EM> or <EM>strings</EM> 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:
+
+ <STRONG>o</STRONG> 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).
+
+ <STRONG>o</STRONG> 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.
+
+ <STRONG>o</STRONG> Other negative values are illegal.
+
+ The <EM>terminal</EM> <EM>names</EM> section comes after the <EM>header</EM>. It contains the
+ first line of the terminfo description, listing the various names for
+ the terminal, separated by the "|" character. The <EM>terminal</EM> <EM>names</EM> 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 <EM>boolean</EM> <EM>flags</EM> 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 <EM>boolean</EM> <EM>flags</EM> section and the <EM>number</EM> section, a null byte
+ will be inserted, if necessary, to ensure that the <EM>number</EM> 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 <EM>numbers</EM> section is similar to the <EM>boolean</EM> <EM>flags</EM> 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 <EM>strings</EM> section is also similar. Each capability is stored as a
+ short integer. The capability value is an index into the <EM>string</EM> <EM>table</EM>.
- 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 <EM>string</EM> <EM>table</EM> is the last section. It contains all of the values of
+ string capabilities referenced in the <EM>strings</EM> 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.
</PRE><H3><a name="h3-EXTENDED-STORAGE-FORMAT">EXTENDED STORAGE FORMAT</a></H3><PRE>
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 <STRONG>ncurses</STRONG> 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. <STRONG>ncurses</STRONG> 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):
(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 <EM>names</EM> as well as extended capability <EM>values</EM>.
+
+ Using the counts and sizes, <STRONG>ncurses</STRONG> 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.
</PRE><H3><a name="h3-EXTENDED-NUMBER-FORMAT">EXTENDED NUMBER FORMAT</a></H3><PRE>
- 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 <STRONG>ncurses</STRONG>
+ 6.1, a new format was introduced by making a few changes to the legacy
format:
- <STRONG>o</STRONG> a different magic number (0542)
+ <STRONG>o</STRONG> a different magic number (octal 01036)
<STRONG>o</STRONG> changing the type for the <EM>number</EM> array from signed 16-bit integers
to signed 32-bit integers.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+
+</PRE><H3><a name="h3-setupterm">setupterm</a></H3><PRE>
Note that it is possible for <STRONG>setupterm</STRONG> to expect a different set of
capabilities than are actually present in the file. Either the data-
base may have been updated since <STRONG>setupterm</STRONG> has been recompiled (result-
new capabilities must always be added at the end of the lists of bool-
ean, number, and string capabilities.
+
+</PRE><H3><a name="h3-Binary-format">Binary format</a></H3><PRE>
+ 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
<STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG> 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.
+
+
+</PRE><H3><a name="h3-Magic-codes">Magic codes</a></H3><PRE>
+ 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 <STRONG>file</STRONG> 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 <STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>). This implementation uses
+ 01036 as a continuation of that sequence, but with a different high-
+ order byte to avoid confusion.
+
+
+</PRE><H3><a name="h3-The-TERMTYPE-structure">The TERMTYPE structure</a></H3><PRE>
Direct access to the <STRONG>TERMTYPE</STRONG> structure is provided for legacy applica-
tions. Portable applications should use the <STRONG>tigetflag</STRONG> and related
functions described in <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG> for reading terminal capabili-
ties.
+
+</PRE><H3><a name="h3-Mixed-case-terminal-names">Mixed-case terminal names</a></H3><PRE>
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, <STRONG>ncurses</STRONG> represents the "first charac-
ter" of the terminal name used as the intermediate level of a directory
tree in (two-character) hexadecimal form.
<STRONG>o</STRONG> the name field cannot exceed 128 bytes.
+ Compiled entries are limited to 32768 bytes because offsets into the
+ <EM>strings</EM> <EM>table</EM> use two-byte integers. The legacy format could have sup-
+ ported 32768-byte entries, but was limited a virtual memory page's 4096
+ bytes.
+
</PRE><H2><a name="h2-FILES">FILES</a></H2><PRE>
/usr/share/terminfo/*/* compiled terminal capability data base
<li><a href="#h3-EXTENDED-NUMBER-FORMAT">EXTENDED NUMBER FORMAT</a></li>
</ul>
</li>
-<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a>
+<ul>
+<li><a href="#h3-setupterm">setupterm</a></li>
+<li><a href="#h3-Binary-format">Binary format</a></li>
+<li><a href="#h3-Magic-codes">Magic codes</a></li>
+<li><a href="#h3-The-TERMTYPE-structure">The TERMTYPE structure</a></li>
+<li><a href="#h3-Mixed-case-terminal-names">Mixed-case terminal names</a></li>
+</ul>
+</li>
<li><a href="#h2-EXAMPLE">EXAMPLE</a></li>
<li><a href="#h2-LIMITS">LIMITS</a></li>
<li><a href="#h2-FILES">FILES</a></li>
projects / ncurses.git / blobdiff