path: root/doc/using-git.texi

\input texinfo   @c -*-texinfo-*-
@c %**start of header (This is for running Texinfo on a region.)
@setfilename using-git.info
@settitle Workflow in the @command{gawk} project
@c %**end of header (This is for running Texinfo on a region.)

@dircategory Network applications
@direntry
* Gawkworkflow: (using-git).         Workflow in the `gawk' project.
@end direntry

@iftex
@set DOCUMENT book
@set CHAPTER chapter
@set SECTION section
@set DARKCORNER @inmargin{@image{lflashlight,1cm}, @image{rflashlight,1cm}}
@end iftex
@ifinfo
@set DOCUMENT Info file
@set CHAPTER major node
@set SECTION node
@set DARKCORNER (d.c.)
@end ifinfo
@ifhtml
@set DOCUMENT web page
@set CHAPTER chapter
@set SECTION section
@set DARKCORNER (d.c.)
@end ifhtml

@set FN file name
@set FFN File Name

@c merge the function and variable indexes into the concept index
@ifinfo
@synindex fn cp
@synindex vr cp
@end ifinfo
@iftex
@syncodeindex fn cp
@syncodeindex vr cp
@end iftex

@c If "finalout" is commented out, the printed output will show
@c black boxes that mark lines that are too long.  Thus, it is
@c unwise to comment it out when running a master in case there are
@c overfulls which are deemed okay.

@iftex
@finalout
@end iftex

@smallbook

@set TITLE Workflow in the @command{gawk} project 
@set EDITION 0.0
@set UPDATE-MONTH August, 2014
@c gawk versions:
@set VERSION 4.1
@set PATCHLEVEL 0

@copying
This is Edition @value{EDITION} of @cite{@value{TITLE}},
for the @value{VERSION}.@value{PATCHLEVEL} (or later) version of the GNU
implementation of AWK.
@sp 2
Copyright (C) 2014, 2015 Free Software Foundation, Inc.
@sp 2
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 the
Invariant Sections being ``GNU General Public License'', the Front-Cover
texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below).  A copy of the license is included in the section entitled
``GNU Free Documentation License''.

@enumerate a
@item
The FSF's Back-Cover Text is: ``You have the freedom to
copy and modify this GNU manual.''
@end enumerate
@end copying

@ifinfo
This file documents the workflow of the developers in the  GNU
@command{awk} project.

@insertcopying
@end ifinfo

@setchapternewpage odd

@titlepage
@title @value{TITLE}
@subtitle Edition @value{EDITION}
@subtitle @value{UPDATE-MONTH}
@author J@"urgen Kahrs
@author with Arnold D. Robbins

@c Include the Distribution inside the titlepage environment so
@c that headings are turned off.  Headings on and off do not work.

@page
@vskip 0pt plus 1filll
@sp 2
Published by:
@sp 1

Free Software Foundation @*
51 Franklin Street, Fifth Floor @*
Boston, MA 02110-1301 USA @*
Phone: +1-617-542-5942 @*
Fax: +1-617-542-2652 @*
Email: @email{gnu@@gnu.org} @*
URL: @uref{http://www.gnu.org/} @*

ISBN 1-882114-93-0 @*

@insertcopying

@c @sp 2
@c Cover art by ?????.
@end titlepage

@iftex
@headings off
@evenheading @thispage@ @ @ @strong{@value{TITLE}} @| @|
@oddheading  @| @| @strong{@thischapter}@ @ @ @thispage
@end iftex

@ifnottex
@node Top
@top Introduction
@comment node-name, next,          previous, up

This file documents the workflow of the developers in the GNU Awk (@command{gawk})
version 4.1 and later.

@insertcopying
@end ifnottex

@menu
* Introduction::                               About networking.
* Basics of GIT repositories::                 The fundamental environment of
                                               the developer.
* Conventions used in the repository::         How to behave.
* Tutorial for a first-time-gawk-contributor:: How to get started with least
                                               pain.
* FAQs and HOWTOs::                            General recipes for daily work.
* Links::                                      Where to find the stuff
                                               mentioned in this document.
* GNU Free Documentation License::             The license for this document.
* Index::                                      The index.

@detailmenu
* Quick Start::         
* Setting up a proper @command{git} repository::               
* Pulling the latest changes from the remote repository::      
* Checking out a feature branch from the remote repository::   
* Semantics of Cloning::                                        What to
                                                                consider
                                                                before you
                                                                clone.
* Local versus Remote::                                         Where my
                                                                source code
                                                                really is.
* Tracking and Merging::                                        What the
                                                                others are
                                                                doing.
* master::                                                     
* stable::                                                     
* feature::                                                    
* who does what::                                               
* step-by-step instructions for a first-time-gawk-contributor::
* step-by-step instructions for a first-time-gawk-administrator::
* general recipes for daily work::                             
* references and URLs to books and other texts::               
@end detailmenu
@end menu

@contents

@node Introduction
@chapter Introduction

This @value{DOCUMENT} is meant to be a description of the working habits
that were established for collaboration in the GNU Awk project.
Such stuff tends to become rather dry, and to prevent you from getting
bored at this early stage, we will begin this @value{CHAPTER} with a
brief introduction that shows you how to get the
source code of the GNU Awk project compiled on your machine.

We do this in order to get you motivated to follow us through the later
steps that consist mainly of conceptual considerations.
We hope that (in later, more abstract steps) you will always remember
this down-to-earth introduction, should you ever wonder what all the
later bizarre trickery is good for.

@menu
* Quick Start::   
* Setting up a proper @command{git} repository::         
* Pulling the latest changes from the remote repository::
* Checking out a feature branch from the remote repository::
@end menu

@node Quick Start
@section Quick Start: Compiling @command{gawk} in 5 Minutes

The following steps will look familiar to you; they are not that much
different from the steps you used in the old days when you downloaded
a tar ball, extracted it and compiled the source code. It is mainly
the very first step that looks different; instead of downloading the
tar ball you need the tool @command{git}.@footnote{If the command
@command{git} does not exist on your machine,
you need adminstrator privileges to install it. By convention, the
command is usually part of an installation package by the same name.}

@example
git clone git://git.savannah.gnu.org/gawk.git
cd gawk
git checkout gawk-4.1-stable
./bootstrap.sh
./configure
make
./gawk --version
@end example

There are two differences to your working habits. In the third step,,
you have to extract (or @dfn{check out}) the @code{gawk-4.1-stable} branch of the current source
code (there are other branches available, that's the point where
things get interesting).

In the fourth step, you must run the @command{bootstrap.sh} script in
order to set correctly timestamps on various files. Doing this is essential;
it allows you to avoid having to install the correct versions of the
various autotools as used by the @command{gawk} maintainer.

Isn't this simple? No, it's not that simple.
If you plan to go any further (for example compile the source
code again next week, including next week's latest update), you will
need to know what's going on when you use this seemingly simple
@command{git} command (and that's the point where things get bizarre).

In the next @value{CHAPTER} you will find a more thorough conceptual
explanation, here we are satisfied with getting to know the practical
steps necessary to get a working environment going that you can use
in your daily work in a reliable way.

@node Setting up a proper @command{git} repository
@section Setting up a proper @command{git} repository

After the initial @emph{checkout} you have access to all the source code
files that the maintainers have pushed through the official release procedure.

You may not have noticed, but each change is well documented and traceable.
This process of tracing the change history is so precise, reproducable and
fine-grained that any dubious change may be kicked out later and the author
of dubious stuff identified by name and change date.

Some bookkeeping is
necessary for this and that's why you need @command{git}. @command{git}
does all this for you. Developers who have used @command{svn} or
@command{cvs} in the past will not be surprised to hear that each change
is traceable precisely (they know that @command{svn} and @command{cvs}
can do this, too).

But the first-time user of @command{git} (as well as the @command{svn} user)
may still have failed to notice what he actually did earlier in this @value{CHAPTER}.
It is not just a mere copy of the source code that you created,
it is a full copy of the entire @dfn{upstream} repository server that you created
(or @dfn{cloned}). This means that others could make their own copy of
@emph{your} repository and treat it as @emph{their upstream} repository.

This is the essential difference between working with @command{svn} and
working with @command{git}: by @emph{cloning} you become a repository
administrator, whether you like it or not. As such you have some duties that
go beyond the duties of an @command{svn} user. For example, you have to
identify yourself properly as the owner of the repository by setting
some global variables identifying you. The global settings will be used
every time you connect again to the upstream repository.

@smallexample
git config --global user.name "@var{First-Name Last-Name}"
git config --global user.email @var{email@@address.site}
git config --global color.ui auto
@end smallexample

You may leave these variables unset, but then you are reduced to an
anonymous consumer-only behaviour whenever you connect to the upstream
repository. Later you will learn that there are many other variables
to be set, most of them serving as defaults that can be overridden if
you like. Choosing to work with defaults makes work quick and easy for the most frequent
use cases, but that comes at a cost: With so many helpful defaults
you may be overwhelmed by the detail and complexity of the real inner working.
Here is an example of one of the author's configuration variables:

@smallexample
$ @kbd{git config --list}
@print{}  user.name=First-Name Last-Name
@print{}  user.email=email@@address.site
@print{}  color.diff=auto
@print{}  color.status=auto
@print{}  color.branch=auto
@print{}  gui.spellingdictionary=en_US
@print{}  core.repositoryformatversion=0
@print{}  core.filemode=true
@print{}  core.logallrefupdaIsn't this simple? No, it's not that simple. tes=true
@print{}  remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
@print{}  remote.origin.url=ssh://jkahrs@@git.sv.gnu.org/srv/git/gawk.git
@print{}  branch.master.remote=origin
@print{}  branch.master.merge=refs/heads/master
@print{}  branch.xgawk_load.remote=origin
@print{}  branch.xgawk_load.merge=refs/heads/xgawk_load
@end smallexample

Changing these variables with specialized variants of the @command{git} command
may seem awkward to you and perhaps you prefer to use your favourite text editor
to overview and change the variables. That's easy: edit the file @file{.git/config}.

@smallexample
$ @kbd{cat .git/config}
@print{} [core]
@print{}         repositoryformatversion = 0
@print{}         filemode = true
@print{}         bare = false
@print{}         logallrefupdates = true
@print{} [remote "origin"]
@print{}         fetch = +refs/heads/*:refs/remotes/origin/*
@print{}         url = ssh://jkahrs@@git.sv.gnu.org/srv/git/gawk.git
@print{} [branch "master"]
@print{}         remote = origin
@print{}         merge = refs/heads/master
@print{} [branch "cmake"]
@print{}         remote = origin
@print{}         merge = refs/heads/cmake
@end smallexample

Now you can see how variables are structured group-wise.
But wait, where is the e-mail address in this list of variables?
It is missing in the file @file{.git/config} because that file
contains only the local settings of this one repository
(while there may be others on your machine).
The e-mail address is a variable of a more general kind that
should be stored above all the repositories.
These are referred to as the @dfn{global} variables:

@smallexample
$ @kbd{git config --list --global}
@print{} user.name=First-Name Last-Name
@print{} user.email=email@@address.site
@print{} color.diff=auto
@print{} color.status=auto
@print{} color.branch=auto
@print{} gui.spellingdictionary=en_US
@end smallexample

If you wonder whether there is a parameter @command{--local} to list
the local variables, then you should look into the well-structured
man pages of @command{git}. The level of detail may overwhelm you,
but one day you might appreciate it.

@smallexample
git help config
@end smallexample

@node Pulling the latest changes from the remote repository
@section Pulling the latest changes from the remote repository

Whether you set any of these variables or not, sooner or later you will want
to catch up with the changes that happened in the upstream repository.
So, how can you update your copy of the repository and re-build the source code?
The easiest way is to rely on defaults and use the @emph{pull} command to request
updates from the upstream repository:

@smallexample
git pull
./bootstrap.sh
./configure
make
@end smallexample

When using the @emph{pull} command, all the changes available in all branches of
the upstream repository will be copied (and merged) into your local repository.
We assume here that we still have the @emph{gawk-4.1-stable} branch checked out (as described earlier)
and we are not interested in changes to other existing branches.
The merging of changes will be done inside the branches only, so that changes in one
branch are kept inside this branch and don't mix up other branches.

@c ========================================

But @emph{what is a branch?} you may wonder. It is the name given to a sequence of changes
that were made to the master branch outside the master branch.
It is easy to look up all the available branches
(the names of the change sequences) in the remote upstream repository.

@smallexample
$ @kbd{git branch -a}
@print{} * master
@print{}   remotes/origin/cmake
@end smallexample

The asterisk in front of the branch name assures you of the fact that you see
the source files as they are in the @emph{master} branch.

@node Checking out a feature branch from the remote repository
@section Checking out a feature branch from the remote repository

It is also easy to
have a look at other branches, for example when you are interested in what is
going on in a certain @emph{feature branch} that the maintainer set up recently
for a new feature to be developed separately (so that others can go on undisturbed).

@smallexample
$ @kbd{git checkout origin/cmake}
$ @kbd{git branch -a}
@print{}   master
@print{} * remotes/origin/cmake
$ @kbd{./bootstrap.sh}
$ @kbd{./configure}
$ @kbd{make}
@end smallexample

When you try this, take care that you have not changed anything in any source file.
@command{git} would notice changes and refuse to checkout the other branch.
This is meant to protect you from losing any local changes that you forgot to save.
Any source file that is part of the repository and gets generated during the build
in a slightly different way than the original would cause such a problem.

@smallexample
$ @kbd{git status}
@print{} # On branch master
@print{} # Changes not staged for commit:
@print{} #       awkgram.c
@end smallexample

Here we have @file{awkgram.c} that was generated from @file{awkgram.y}.
But what was generated differently in the file?

@smallexample
git diff awkgram.c
@end smallexample

Ok, you are not interested in textual changes to the copyright notice
that are only due to a new calendar year. You are also not interested
in the internals of the generated parser and only wonder
@emph{How do we get back the original file from the repository?}

@smallexample
$ @kbd{git checkout awkgram.c}
$ @kbd{git diff awkgram.c | wc -l}
@print{} 0
@end smallexample

After checking the file out once more, there is obviously no difference
to the copy saved in the repository. But let's not get distracted, we
wanted to find out what was going on in this feature branch. We can
find out by asking @command{git} what has changed in the file @file{ChangeLog}
of this feature branch relative to the master branch.

@smallexample
git diff origin/master ChangeLog
@end smallexample

@noindent
This produces:

@smallexample
diff --git a/ChangeLog b/ChangeLog
index eab657c..a499ec5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,81 +1,3 @@
-2014-09-07         Arnold D. Robbins     <arnold@@skeeve.com>
-
-       * awk.h: Move libsigsegv stuff to ...
-       * main.c: here. Thanks to Yehezkel Bernat for motivating
-       the cleanup.
-       * symbol.c (make_symbol, install, install_symbol): Add const to
-       first parameter. Adjust decls and fix up uses.
@end smallexample

Looks like a minor cleanup operation in the master branch that has not
yet been merged into the feature branch. We still don't know what is new
in this feature branch, how can we know? By looking at all changes that exist.

@smallexample
$ @kbd{git diff origin/master --numstat}
@print{} 0       78      ChangeLog
@print{} 8       3       README_d/README.cmake
@end smallexample

On your screen you see a list of all differences between the currently
checked-out branch and the master branch. It tells you the names of the
files that have changed, along with the number of added and deleted lines.
Now we can have a closer look at who changed what.
Let's single out one particular file that looks interesting.
As usual there is a @command{diff} sub-command to list all the changed
lines, but there is also a @command{blame} sub-command that tells you
who made the last change to any of the lines.

@smallexample
git blame README_d/README.cmake
@end smallexample

@noindent
This produces (in part):

@smallexample
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   1) CMake is a build automation system
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   2)   http://en.wikipedia.org/wiki/Cmake
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   3) 
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   4) We try to use it as a replacement for the established GNU build system.
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   5) This attempt is currently only experimental. If you wonder why anyone
2092a35f (Juergen Kahrs     2014-08-12 17:11:20 +0200   6) should do this, read
@end smallexample

The strange number on the left margin is the short form of a numerical
identifier of the change set. At the moment you can safely ignore it,
but this number is the key you need in case you should ever want to
cherry-pick some change sets. But cherry-picking is still far away,
before you can do this, you have to learn how to make changes to your
local repository and @command{push} them to the upstream repository.
Some conceptual basics are needed for understanding this essential part
of the workflow.

@node Basics of GIT repositories
@chapter Basics of GIT repositories

@menu
* Semantics of Cloning::        What to consider before you clone.
* Local versus Remote::         Where my source code really is.
* Tracking and Merging::        What the others are doing.
@end menu

@c http://iverilog.wikia.com/wiki/Installation_Guide
@c http://www.linuxjournal.com/article/2840
@c http://git-scm.com/book/en/Git-Branching-Branching-Workflows
@c https://www.atlassian.com/en/git/workflows
@c https://help.github.com/articles/what-is-a-good-git-workflow
@c https://guides.github.com/introduction/flow/index.html
@c http://supercollider.sourceforge.net/wiki/index.php/Developer_cheatsheet_for_git
@c http://savannah.gnu.org/maintenance/UsingGit/
@c http://www.emacswiki.org/emacs/GitForEmacsDevs

What is tracking ?

@display
- How can I use git to contribute source code ?
You need an account at Savannah. Read this to understand the first steps:
  http://savannah.gnu.org/maintenance/UsingGit
  README.git
Use your account there to register your public ssh key at Savannah.
Then you are ready to checkout. Remember that (when cloning) you are
setting up your own local repository and make sure you configure it
properly.
  git clone ssh://my_account_name@@git.sv.gnu.org/srv/git/gawk.git
@end display

@node Semantics of Cloning
@section Semantics of Cloning

@node Local versus Remote
@section Local versus Remote

@node Tracking and Merging
@section Tracking and Merging

@node Conventions used in the repository
@chapter Conventions used in the repository

@menu
* master::                     
* stable::                     
* feature::                    
* who does what::               
@end menu

@node master
@section master

@node stable
@section stable

@node feature
@section feature

@node who does what
@section who does what

@node Tutorial for a first-time-gawk-contributor
@chapter Tutorial for a first-time-gawk-contributor

@menu
* step-by-step instructions for a first-time-gawk-contributor::
* step-by-step instructions for a first-time-gawk-administrator::
@end menu

@node step-by-step instructions for a first-time-gawk-contributor
@section step-by-step instructions for a first-time-gawk-contributor

@node step-by-step instructions for a first-time-gawk-administrator
@section step-by-step instructions for a first-time-gawk-administrator

@c e-mail from Arnold 2014-08.24
@c Thanks to Michal for pointing us in the right direction!
@c I see this:
@c 
@c bash-4.2$ git config --get push.default
@c simple
@c 
@c What does yours say?
@c 
@c It appears that "simple" will be the default in version 2.0:
@c 
@c From:
@c http://blog.nicoschuele.com/posts/git-2-0-changes-push-default-to-simple
@c 
@c Matching
@c 
@c The 'matching' option is the default behavior in Git 1.x. It means that if you do a git push without specifying a branch, it will push all your local branches to their matching ones on your remote repository.
@c 
@c Simple
@c 
@c The new default in Git 2.x is 'simple'. It means that when doing a git push without specifying a branch, only your current branch will be pushed to the one git pull would normally get your code from."
@c 
@c So this must explain it.  I'll bet yours is set to "matching".  I have no
@c idea how mine got set to "simple", since I don't recall doing that.
@c 
@c In the future, I will simply make sure to push before switching branches.
@c I think I actually prefer that behavior, since it's more intuitive to me.


@node FAQs and HOWTOs
@chapter FAQs and HOWTOs

@menu
* general recipes for daily work::
@end menu

@node general recipes for daily work
@section general recipes for daily work

@node Links
@chapter Links

@menu
* references and URLs to books and other texts::
@end menu

@node references and URLs to books and other texts
@section references and URLs to books and other texts

@c The GNU Free Documentation License.
@node GNU Free Documentation License
@unnumbered GNU Free Documentation License
@cindex FDL (Free Documentation License)
@cindex Free Documentation License (FDL)
@cindex GNU Free Documentation License
@center Version 1.3, 3 November 2008

@c This file is intended to be included within another document,
@c hence no sectioning command or @node.

@display
Copyright @copyright{} 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
@uref{http://fsf.org/}

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
@end display

@enumerate 0
@item
PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document @dfn{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.

@item
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
@sc{ascii} without markup, Texinfo input format, La@TeX{} input
format, @acronym{SGML} or @acronym{XML} using a publicly available
@acronym{DTD}, and standard-conforming simple @acronym{HTML},
PostScript or @acronym{PDF} designed for human modification.  Examples
of transparent image formats include @acronym{PNG}, @acronym{XCF} and
@acronym{JPG}.  Opaque formats include proprietary formats that can be
read and edited only by proprietary word processors, @acronym{SGML} or
@acronym{XML} for which the @acronym{DTD} and/or processing tools are
not generally available, and the machine-generated @acronym{HTML},
PostScript or @acronym{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.

@item
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.

@item
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.

@item
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:

@enumerate A
@item
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.

@item
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.

@item
State on the Title page the name of the publisher of the
Modified Version, as the publisher.

@item
Preserve all the copyright notices of the Document.

@item
Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.

@item
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.

@item
Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document's license notice.

@item
Include an unaltered copy of this License.

@item
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.

@item
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.

@item
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.

@item
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.

@item
Delete any section Entitled ``Endorsements''.  Such a section
may not be included in the Modified Version.

@item
Do not retitle any existing section to be Entitled ``Endorsements'' or
to conflict in title with any Invariant Section.

@item
Preserve any Warranty Disclaimers.
@end enumerate

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.

@item
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.''

@item
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.

@item
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.

@item
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.

@item
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.

@item
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
@uref{http://www.gnu.org/copyleft/}.

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.

@item
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.

@end enumerate

@c fakenode --- for prepinfo
@unnumberedsec 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:

@smallexample
@group
  Copyright (C)  @var{year}  @var{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''.
@end group
@end smallexample

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the ``with@dots{}Texts.'' line with this:

@smallexample
@group
    with the Invariant Sections being @var{list their titles}, with
    the Front-Cover Texts being @var{list}, and with the Back-Cover Texts
    being @var{list}.
@end group
@end smallexample

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.

@c Local Variables:
@c ispell-local-pdict: "ispell-dict"
@c End:


@node Index
@comment node-name,    next,  previous,      up

@unnumbered Index
@printindex cp
@bye

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