ctlseqs
1 Overview of ctlseqs
2 Helper Macros
3 Control Sequence Matching
4 Control Sequence Reading
5 Tips & Hints
6 Example Programs
Appendix A API Reference
Appendix B General Index
Appendix C GNU Free Documentation License
ctlseqs
1 Overview of ctlseqs
1.1 Contributing
1.2 Use Scenarios of ctlseqs
2 Helper Macros
3 Control Sequence Matching
3.1 Matcher Configuration
3.1.1 Patterns
3.2 Matching String
4 Control Sequence Reading
5 Tips & Hints
6 Example Programs
Appendix A API Reference
Appendix B General Index
Appendix C GNU Free Documentation License
ctlseqs
*******
This manual is for ctlseqs, a helper library for control sequences.
Permission is granted to copy, distribute and/or modify this document
under the terms of the *note GNU Free Documentation License::, Version
1.3 or any later version published by the Free Software Foundation; with
no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts.
ctlseqs is free software. You can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
1 Overview of ctlseqs
*********************
The name "ctlseqs" is an abbreviation of "control sequences", as defined
in section 5.4 of ECMA-48.
As the name suggests, this library focuses on handling control
sequences. However, it only cares about the bit combinations, while the
actual meaning and implementation of a control sequence is up to the
user.
The C API provided by ctlseqs is composed of three major parts: The
helper macros, the control sequence matcher, and the control sequence
reader. Any of them can be used separatedly or combined, after
including the header file 'ctlseqs.h' in a source file.
1.1 Contributing
================
We welcome any form of contribution to ctlseqs (as well as this manual),
including bug reports, patches, etc.
Source code of ctlseqs is hosted on Savannah
(https://savannah.nongnu.org/projects/ctlseqs). You can contribute to
ctlseqs using the bug tracker and patch manager, or discuss with the
community using the mailing lists.
1.2 Use Scenarios of ctlseqs
============================
Control sequences, as well as other control functions, were once
commonly used in computer terminals. Terminals exchange control
information with the host regarding colors, font styles, cursor
position, etc., using control functions embedded in normal text. Such
physical terminals are no longer used today, however, popular ones like
DEC VT100 are widely emulated by modern terminal emulators.
The primary purpose of the ctlseqs library is to provide developers
with simple and easy-to-use API for handling control functions, when
working on terminal emulators and text-based programs.
However, since there is no de facto standard, control functions used
in terminals are largely vendor-specific, and terminal emulators like to
add their own private controls. That makes ctlseqs not suitable for
writing text-based programs which intend to be portable. Instead of raw
control codes, developers should stick to ncurses or terminfo.
There are still cases when dealing with raw escape sequences is
inevitable, and ctlseqs may come in handy:
* Development of text-based programs which rely heavily on special
control sequences, which is not supported by libraries like
ncurses.
* Implementing a terminal emulator.
* Experimenting or debugging the features of text-based programs or
terminal emulators.
2 Helper Macros
***************
ctlseqs provides C preprocessor macros representing control functions,
which expand to C string literals.
The control function can be one of the following three types:
* Elements from the C0 or C1 set.
* Control Sequences.
* Other control functions (such as device control functions).
The name of a helper macro is the control function name with
'CTLSEQS_' as prefix. For a control function other than elements from
the C0 or C1 set, the corresponding helper macro is a function-like
macro which may or may not take arguments.
Control sequences listed in the helper macros are primarily excerpted
from XTerm's manual
(https://invisible-island.net/xterm/ctlseqs/ctlseqs.html), which may
differ across implementations.
As ctlseqs does not currently support 8-bit controls, 2-character
7-bit codes from the C1 set are used instead of their 1-character 8-bit
representation. For example, 'CTLSEQS_CSI' expands to '"\x1b["'.
The following code snippet is an example usage of helper macros:
printf(CTLSEQS_BEL);
printf(CTLSEQS_XTVERSION());
printf(CTLSEQS_CUP("%d", "%d"), 3, 4);
Keep in mind that the standard output stream is line buffered in a
terminal. Either 'fflush(stdout)' after printing, or disable output
buffering with 'setvbuf(stdout, NULL, _IONBF, 0)'.
3 Control Sequence Matching
***************************
Given a character string, checking whether it matches a control sequence
is quite trivial, with only the standard C library:
char const *str /* = ... */;
int row, col;
if (0 == strcmp(str, CTLSEQS_XTVERSION())) {
// ...
} else if (2 == sscanf(str, CTLSEQS_CUP("%d", "%d"), &row, &col)) {
// ...
} else {
// ...
}
However, as the number of possible matches grows, this naive
implementation becomes less efficient and harder to maintain.
Such problems can be easily solved by using the control sequence
matcher provided by ctlseqs.
The 'struct ctlseqs_matcher *' is a pointer to an opaque type which
represents an instance of control sequence matcher. Before using, the
matcher should be initialized with 'ctlseqs_matcher_init'. After used,
it should be deallocated with 'ctlseqs_matcher_free'.
struct ctlseqs_matcher *matcher = ctlseqs_matcher_init();
// ...
ctlseqs_matcher_free(matcher);
On rare occurences when ctlseqs fail to allocate enough memory,
function 'ctlseqs_matcher_init' may return 'NULL'. However, it is safe
to pass null pointers to 'ctlseqs_matcher_free'.
3.1 Matcher Configuration
=========================
Matcher configuration consists of two parts: the number of matching
patterns, and the pattern values. Invoke function
'ctlseqs_matcher_config' to configure a matcher.
struct ctlseqs_matcher *matcher /* = ... */;
char const *patterns[] = {
// ...
};
struct ctlseqs_matcher_options options = {
.patterns = patterns,
.npatterns = sizeof(patterns) / sizeof(char const *),
};
int result = ctlseqs_matcher_config(matcher, &options);
// ...
Each invocation of 'ctlseqs_matcher_config' on the same matcher
overwrites the data generated from the last invocation. Upon success,
the function returns 'CTLSEQS_OK'. If the function fails to allocate
enough memory, returns 'CTLSEQS_NOMEM'.
Caution: If the 'patterns' field in 'struct
ctlseqs_matcher_options' is invalid, function behaviour is
undefined. See *note Patterns:: for details.
3.1.1 Patterns
--------------
The 'patterns' field in 'struct ctlseqs_matcher_options' is an array of
NUL-terminated strings which indicates the desired patterns of control
functions for the current matcher.
The following types of control functions are recognizable by the
matcher:
* Control sequences: 'CSI [param...] [intmd...] final'
* C1 functions with command string: '(APC|DCS|OSC|PM) [cmdstr] ST'
* Single shifts: '(SS2|SS3) ch'
* SOS function: 'SOS [chrstr] ST'
According to ECMA-48, CSI parameter bytes are of range '0x30' to
'0x3f', intermediate bytes '0x20' to '0x2f', and final byte '0x40' to
'0x7e'. Command string consists of printable characters and characters
of range '0x08' and '0x0e'. Character string can be any bit combination
which does not represent 'SOS' or 'ST'.
A supported control function, either verbatim or combined with
placeholders, can be specified as a valid pattern. The terminating
'NUL' character does not count into the pattern.
A placeholder indicates that when matching a string against the
pattern, the value at the placeholder's location should conform to its
rules. A placeholder can only take place in the 'param', 'intmd',
'cmdstr' or 'chrstr' fields, and can be one of the following values:
* 'CTLSEQS_PH_NUM': An unsigned integer.
* 'CTLSEQS_PH_NUMS': Multiple unsigned integers separated with the
semicolon ASCII character (value '0x3b').
* 'CTLSEQS_PH_STR': A string of printable characters.
* 'CTLSEQS_PH_CMDSTR': A string containing only printable characters
and characters of range '0x08' to '0x0d'.
* 'CTLSEQS_PH_CSI_PARAM': A string of CSI parameter bytes.
* 'CTLSEQS_PH_CSI_INTMD': A string of CSI intermediate bytes.
* 'CTLSEQS_PH_HEXNUM': A string representing a hexadecimal number.
* 'CTLSEQS_PH_CHRSTR': A string of any bit combination which does not
represent 'SOS' or 'ST'.
The following code is a valid example of patterns:
const char *patterns[] = {
CTLSEQS_CUP(CTLSEQS_PH_NUM, CTLSEQS_PH_NUM),
CTLSEQS_XTVERSION(),
CTLSEQS_DECRQM("1000"),
// ...
};
3.2 Matching String
===================
Function 'ctlseqs_match' matches a given character string to a matcher.
The function accepts four arguments: the matcher, the string to match,
length of the string to match, and a buffer which stores the match
result.
Before matching, a buffer which is large enough to store the match
result should be allocated. The buffer is an array of 'union
ctlseqs_value', whose definition is shown below:
union ctlseqs_value {
char const *str;
size_t len;
unsigned long num;
};
If the string contains a recognizable control function, or part of a
control function which is not yet terminated by the end of the string,
the length of control function will be stored at 'len' field of match
result buffer at offset 0, and the pointer to the first character of the
control funtion at the 'str' field at offset 1.
If 'ctlseqs_match' fails to find any control functions, returns
'CTLSEQS_NOSEQ'. For a partial control function, returns
'CTLSEQS_PARTIAL'. If the matcher is not configured with a matching
pattern of the control function, the function returns 'CTLSEQS_NOMATCH'.
If the control function matches a pattern configured in the matcher,
returns the offset of the matched pattern, and stores the extracted
values to the result buffer according to each of the placeholders,
starting from offset 2:
* 'CTLSEQS_PH_NUM', 'CTLSEQS_PH_HEXNUM': The integer is stored in
field 'num'.
* 'CTLSEQS_PH_NUMS': The number of integers is stored in field 'len',
followed by that many integers stored in field 'num'.
* 'CTLSEQS_PH_CSI_PARAM', 'CTLSEQS_PH_CSI_INTMD', 'CTLSEQS_PH_STR',
'CTLSEQS_PH_CMDSTR', 'CTLSEQS_PH_CHRSTR': The length of the string
is stored in field 'len', followed by a pointer to the first
character of the string stored in field 'str'.
The following code is an example of invoking 'ctlseqs_match':
union ctlseqs_value buffer[4];
struct ctlseqs_matcher *matcher /* = ... */;
// ...
char const *str = "foo" CTLSEQS_CUP("2", "4");
size_t str_len = sizeof("foo" CTLSEQS_CUP("2", "4")) - 1;
ssize_t result = ctlseqs_match(matcher, str, str_len, buffer);
assert(result == 0);
assert(buffer[0].len == 6 && buffer[1].str == str + 3);
assert(buffer[2].num == 2 && buffer[3].num == 4);
Function 'ctlseqs_match' allows 'NULL' value for argument 'matcher',
in which case it behaves like a matcher configured with zero patterns is
provided.
Caution: If the given string can match multiple patterns in the
matcher, it is unspecified which one of them will be the final
match result.
4 Control Sequence Reading
**************************
5 Tips & Hints
**************
6 Example Programs
******************
In the source code repository of ctlseqs, there are a few programs that
demonstrates the basic usage of ctlseqs.
See "example/sixdraw.c" for a simple TUI program in which you can
draw lines on the terminal window using a mouse.
See "tests/tcsgrep.c" for a program which parses control functions
into human-readable text. It was originally written as a tool to run
tests for ctlseqs, but can also be considered as a crude alternative of
GNU Teseq (https://www.gnu.org/software/teseq/).
Appendix A API Reference
************************
This section contains a complete list of functions exposed by ctlseqs.
See the corresponding man pages for details.
Initialize matcher
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_matcher_init.3.html):
struct ctlseqs_matcher *ctlseqs_matcher_init(void);
Configure matcher
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_matcher_config.3.html):
int ctlseqs_matcher_config(
struct ctlseqs_matcher *matcher,
struct ctlseqs_matcher_options const *options
);
Match string
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_match.3.html):
ssize_t ctlseqs_match(
struct ctlseqs_reader const *matcher,
char const *str,
size_t str_len,
union ctlseqs_value *result
);
Destroy matcher
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_matcher_free.3.html):
void ctlseqs_matcher_free(
struct ctlseqs_matcher *matcher
);
Initialize reader
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_reader_init.3.html):
struct ctlseqs_reader *ctlseqs_reader_init(void);
Configure reader
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_reader_config.3.html):
int ctlseqs_reader_config(
struct ctlseqs_reader *reader,
struct ctlseqs_reader_options const *options
);
Read and match
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_read.3.html):
ssize_t ctlseqs_read(
struct ctlseqs_reader *reader,
struct ctlseqs_matcher const *matcher,
int timeout
);
Purge reader
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_purge.3.html):
void ctlseqs_purge(
struct ctlseqs_reader *reader,
size_t nbytes
);
Destroy reader
(https://nongnu.org/ctlseqs/man-pages/man3/ctlseqs_reader_free.3.html):
void ctlseqs_reader_free(
struct ctlseqs_reader *reader
);
Appendix B General Index
************************
* Menu:
* Control functions supported by the matcher: Patterns. (line 203)
* Control sequence matcher configuration example: Matcher Configuration.
(line 176)
* Control sequence matcher initialization example: Control Sequence Matching.
(line 161)
* Control sequence matcher pattern example: Patterns. (line 238)
* Helper macro usage example: Helper Macros. (line 124)
* List of common use cases of ctlseqs: Use Scenarios. (line 88)
* List of control function types in ctlseqs helper macros: Helper Macros.
(line 104)
* List of supported placeholders: Patterns. (line 221)
Appendix C GNU Free Documentation License
*****************************************
Version 1.3, 3 November 2008
Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book. We
recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it can
be distributed under the terms of this License. Such a notice
grants a world-wide, royalty-free license, unlimited in duration,
to use that work under the conditions stated herein. The
"Document", below, refers to any such manual or work. Any member
of the public is a licensee, and is addressed as "you". You accept
the license if you copy, modify or distribute the work in a way
requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could
fall directly within that overall subject. (Thus, if the Document
is in part a textbook of mathematics, a Secondary Section may not
explain any mathematics.) The relationship could be a matter of
historical connection with the subject or with related matters, or
of legal, commercial, philosophical, ethical or political position
regarding them.
The "Invariant Sections" are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License.
If a section does not fit the above definition of Secondary then it
is not allowed to be designated as Invariant. The Document may
contain zero Invariant Sections. If the Document does not identify
any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice
that says that the Document is released under this License. A
Front-Cover Text may be at most 5 words, and a Back-Cover Text may
be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed
of pixels) generic paint programs or (for drawings) some widely
available drawing editor, and that is suitable for input to text
formatters or for automatic translation to a variety of formats
suitable for input to text formatters. A copy made in an otherwise
Transparent file format whose markup, or absence of markup, has
been arranged to thwart or discourage subsequent modification by
readers is not Transparent. An image format is not Transparent if
used for any substantial amount of text. A copy that is not
"Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format,
SGML or XML using a publicly available DTD, and standard-conforming
simple HTML, PostScript or PDF designed for human modification.
Examples of transparent image formats include PNG, XCF and JPG.
Opaque formats include proprietary formats that can be read and
edited only by proprietary word processors, SGML or XML for which
the DTD and/or processing tools are not generally available, and
the machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For
works in formats which do not have any title page as such, "Title
Page" means the text near the most prominent appearance of the
work's title, preceding the beginning of the body of the text.
The "publisher" means any person or entity that distributes copies
of the Document to the public.
A section "Entitled XYZ" means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
stands for a specific section name mentioned below, such as
"Acknowledgements", "Dedications", "Endorsements", or "History".)
To "Preserve the Title" of such a section when you modify the
Document means that it remains a section "Entitled XYZ" according
to this definition.
The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow the
conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the title
equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as
long as they preserve the title of the Document and satisfy these
conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with
each Opaque copy a computer-network location from which the general
network-using public has access to download using public-standard
network protocols a complete Transparent copy of the Document, free
of added material. If you use the latter option, you must take
reasonably prudent steps, when you begin distribution of Opaque
copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or
through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies,
to give them a chance to provide you with an updated version of the
Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with the
Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever
possesses a copy of it. In addition, you must do these things in
the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of previous
versions (which should, if there were any, be listed in the
History section of the Document). You may use the same title
as a previous version if the original publisher of that
version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the
Title Page. If there is no section Entitled "History" in the
Document, create one stating the title, year, authors, and
publisher of the Document as given on its Title Page, then add
an item describing the Modified Version as stated in the
previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in the
"History" section. You may omit a network location for a work
that was published at least four years before the Document
itself, or if the original publisher of the version it refers
to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the section
all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered
in their text and in their titles. Section numbers or the
equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option designate
some or all of these sections as invariant. To do this, add their
titles to the list of Invariant Sections in the Modified Version's
license notice. These titles must be distinct from any other
section titles.
You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of
the list of Cover Texts in the Modified Version. Only one passage
of Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document
already includes a cover text for the same cover, previously added
by you or by arrangement made by the same entity you are acting on
behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added
the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination all
of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the documents
in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense, or distribute it is void,
and will automatically terminate your rights under this License.
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from you
under this License. If your rights have been terminated and not
permanently reinstated, receipt of a copy of some or all of the
same material does not give you any rights to use it.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may
choose any version ever published (not as a draft) by the Free
Software Foundation. If the Document specifies that a proxy can
decide which future versions of this License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Document.
11. RELICENSING
"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A
public wiki that anybody can edit is an example of such a server.
A "Massive Multiauthor Collaboration" (or "MMC") contained in the
site means any set of copyrightable works thus published on the MMC
site.
"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
"Incorporate" means to publish or republish a Document, in whole or
in part, as part of another Document.
An MMC is "eligible for relicensing" if it is licensed under this
License, and if all works that were first published under this
License somewhere other than this MMC, and subsequently
incorporated in whole or in part into the MMC, (1) had no cover
texts or invariant sections, and (2) were thus incorporated prior
to November 1, 2008.
The operator of an MMC Site may republish an MMC contained in the
site under CC-BY-SA on the same site at any time before August 1,
2009, provided the MMC is eligible for relicensing.
ADDENDUM: How to use this License for your documents
====================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.