Simplify, do not install examples or info manual, and change license3.1.7

Signed-off-by: Mattias Andrée <maandree@kth.se>

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-\input texinfo   @c -*-texinfo-*-
-
-@c %**start of header
-@setfilename bus.info
-@settitle bus
-@afourpaper
-@documentencoding UTF-8
-@documentlanguage en
-@finalout
-@c %**end of header
-
-
-@dircategory Interprorcess Communication
-@direntry
-* bus: (bus).                        A simple daemonless system for broadcasting messages locally
-@end direntry
-
-
-@copying
-Copyright @copyright{} 2015 Mattias Andrée
-
-@quotation
-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, with no Front-Cover Texts, and with no Back-Cover
-Texts. A copy of the license is included in the section entitled
-``GNU Free Documentation License''.
-@end quotation
-@end copying
-
-@ifnottex
-@node Top
-@top bus -- A simple daemonless system for broadcasting messages locally
-@insertcopying
-@end ifnottex
-
-@titlepage
-@title bus
-@subtitle A simple daemonless system for broadcasting messages locally
-@author by Mattias Andrée (maandree)
-
-@page
-@vskip 0pt plus 1filll
-@insertcopying
-@page
-@end titlepage
-
-@contents
-
-
-@iftex
-@macro xrm{}
-@rm{}
-@end macro
-@macro xtt{}
-@tt{}
-@end macro
-@end iftex
-
-@ifnottex
-@macro xrm{}
-@end macro
-@macro xtt{}
-@end macro
-@end ifnottex
-
-@menu
-* Overview::                        Brief overview of @command{bus}.
-* Standard::                        How to use @command{bus} properly.
-* Invoking::                        Executing @command{bus}.
-* Interface::                       Using @command{libbus}.
-* Protocol::                        How communication over @command{bus} works internally.
-* Rationale::                       Why @command{bus}?
-* Examples::                        Usecase examples and API-demonstration.
-* GNU Free Documentation License::  Copying and sharing this manual.
-
-@detailmenu
- --- The Detailed Node Listing ---
-
-Invoking
-
-* bus create::                      Create a bus.
-* bus remove::                      Remove a bus.
-* bus listen::                      Listen for new message on a bus.
-* bus wait::                        Listen for one new message only on a bus.
-* bus broadcast::                   Broadcast a message on a bus.
-* bus chmod::                       Change permissions on a bus.
-* bus chown::                       Change ownership of a bus.
-* bus chgrp::                       Change group ownership of a bus.
-
-Examples
-
-* Audio-volume control::
-* Telephony and music::
-* Timed::
-* Nonblocking::
-* Daemon-dependencies::
-
-@end detailmenu
-@end menu
-
-
-
-@node Overview
-@chapter Overview
-
-@command{bus} is a stupid-simple, thrilless, daemonless interprocess
-communication system for broadcasting messages. It is a lightweight
-alternative to a two-phase interprocess flexible barrier.
-
-@command{bus} uses a System V semaphore array and System V shared
-memory. Buses are named; the key of the semaphore array and the
-shared memory is stored in a regular file.
-
-The shared memory used by @command{bus} is always 2048 bytes.
-Additionally all messages should be encoded in UTF-8 and not contain
-any NULL characters, except they @emph{must} always end with a NULL
-byte. Furthermore messages should be prefixed with the process
-identifer of the process whence the message originated, followed
-by a space. If the process is ephemeral@footnote{The process exits
-after the broadcast, or shortly thereafter.}, 0 should be used
-instead of the process identifier.
-
-Communication over @command{bus} is synchronous. The broadcast call
-does not return until all listeners have received (and copied) the
-message. A malfunctioning program can lock the bus.
-
-This software package contains a C library and a command line
-utility. The package python-bus provides a Python 3 module.
-
-
-
-@node Standard
-@chapter Standard
-
-The command @command{bus create} can be used to create new buses. By
-convention, buses should be stored in @file{$XDG_RUNTIME_DIR/bus},
-this is what @command{bus create} does if no pathname is given. The
-pathname of the bus should be tracked using @env{BUS_X}, where @env{X}
-is replaced with either:
-
-@table @env
-@item GENERIC
-For the bus used in generic cases. That is all but the cases
-of the buses listed below.
-@item AUDIO
-For the bus used in with the audio subsystem is involved.
-@item VIDEO
-For the bus used in with the video subsystem is involved.
-@item INPUT
-For the bus used in with the input subsystem is involved.
-@item FILES
-For the bus used in with the storage subsystem is involved.
-@end table
-
-This list may be extended in the future. Therefore, and for
-other conventions, project-private buses should be tracked
-using @env{X_BUS}, where @env{X} is the project name.
-
-Messages broadcasted on a bus cannot be longer than 2047 bytes,
-excluding NUL termination. Message should be encoded in UTF-8,
-and most not contain the NUL character.
-
-Broadcasted message should start with the process ID whence
-the message originated, followed by a single regular space.
-If the process is ephemeral@footnote{The process exits after
-the broadcast, or shortly thereafter.}, 0 should be used instead
-of the process identifier.
-
-
-
-@node Invoking
-@chapter Invoking
-
-@command{bus} includes the following commands:
-
-@table @command
-@item create
-Create a bus.
-See @ref{bus create} for more information.
-@item remove
-Remove a bus.
-See @ref{bus remove} for more information.
-@item listen
-Listen for new message on a bus.
-See @ref{bus listen} for more information.
-@item wait
-Listen for one new message only on a bus.
-See @ref{bus wait} for more information.
-@item broadcast
-Broadcast a message on a bus.
-See @ref{bus broadcast} for more information.
-@item chmod
-Change permissions on a bus.
-See @ref{bus chmod} for more information.
-@item chown
-Change ownership of a bus.
-See @ref{bus chown} for more information.
-@item chgrp
-Change group ownership of a bus.
-See @ref{bus chgrp} for more information.
-@end table
-
-Upon successful completion, these commands exit with the value
-0. On failure, they exit with the value 1. If the command is
-not recognised the exit value is 2.
-
-@menu
-* bus create::                      Create a bus.
-* bus remove::                      Remove a bus.
-* bus listen::                      Listen for new message on a bus.
-* bus wait::                        Listen for one new message only on a bus.
-* bus broadcast::                   Broadcast a message on a bus.
-* bus chmod::                       Change permissions on a bus.
-* bus chown::                       Change ownership of a bus.
-* bus chgrp::                       Change group ownership of a bus.
-@end menu
-
-
-
-@node bus create
-@section @command{bus create}
-
-The syntax for invocation of @command{bus create} is
-@example
-bus create [-x] [--] [@var{PATHNAME}]
-@end example
-
-The command creates a bus and stores the key to it in the
-file @var{PATHNAME}. If @var{PATHNAME} is omitted, a
-random pathname in @file{$XDG_RUNTIME_DIR/bus} will be
-used and printed to stdout.
-
-If @option{-x} is used, the command will fail if
-the file @var{PATHNAME} already exists.
-
-
-
-
-@node bus remove
-@section @command{bus remove}
-
-The syntax for invocation of @command{bus remove} is
-@example
-bus remove [--] @var{PATHNAME}
-@end example
-
-The command removes the bus whose key is stored in
-the file @var{PATHNAME}.  The file holding the
-key is also unlinked.
-
-
-
-@node bus listen
-@section @command{bus listen}
-
-The syntax for invocation of @command{bus command} is
-@example
-bus listen [--] @var{PATHNAME} @var{COMMAND}
-@end example
-
-The command listens for new messages on the bus whose
-key is stored in the file @var{PATHNAME}. Once a message
-is received, @var{COMMAND} will be spawned with the
-environment variable @env{msg} (lowercased) set to the
-received message. @sc{POSIX} shell syntax applies to
-@var{COMMAND}.
-
-
-@node bus wait
-@section @command{bus wait}
-
-The syntax for invocation of @command{bus wait} is
-@example
-bus wait [--] @var{PATHNAME} @var{COMMAND}
-@end example
-
-The command listens for a new message on the bus whose
-key is stored in the file @var{PATHNAME}. Once a message
-is received, the process will stop listening for more
-messages and @var{COMMAND} will be spawned with the
-environment variable @env{msg} (lowercased) set to the
-received message. @sc{POSIX} shell syntax applies to
-@var{COMMAND}.
-
-
-
-@node bus broadcast
-@section @command{bus broadcast}
-
-The syntax for invocation of @command{bus broadcast} is
-@example
-bus broadcast [-n] [--] @var{PATHNAME} @var{MESSAGE}
-@end example
-
-The command broadcasts the message @var{MESSAGE} on the
-bus whose key is stored in the file @var{PATHNAME}.
-
-
-
-@node bus chmod
-@section @command{bus chmod}
-
-The syntax for invocation of @command{bus chmod} is
-@example
-bus chmod [--] @var{PERMISSIONS} @var{PATHNAME}
-@end example
-
-This command changes who have access to the bus whose key
-is stored in the file @var{PATHNAME}. In the permissions,
-the owner, the group, and others (not in tgroup) are
-represented by the symbols @code{u}@footnote{@code{u}
-stands for `user'.}, @code{g}, and @code{o}, respectively.
-The permissions string is imagined to have always be
-prefixed with an @code{=}. This symbols means that all user
-classes list after it, and only those classes, as permission
-to use the bus. Similarly the symbols @code{+} and @code{-}
-can be used to grant and revoke access, respectively. The
-symbols @code{=}, @code{+}, and @code{-} can be mixed, and
-are interpreted from left to right. Alternatively the
-permissions string can be a octal number, where the  owner
-is represented by any bit in 700 (100, 200, or 400, or any
-combination thereof), the group is represented by any bit
-in 70, and others (not in the group) is represented by any
-bit in 7.
-
-The current permission of the bus can be retrieved by
-running @command{stat} over the file @var{PATHNAME}.
-
-
-
-@node bus chown
-@section @command{bus chown}
-
-The syntax for invocation of @command{bus chown} is
-@example
-bus chown [--] @var{OWNER}[:@var{GROUP}] @var{PATHNAME}
-@end example
-
-This command changes the owner, that owns the bus whose
-key is stored in the file @var{PATHNAME}, to the specified
-owner. The owner can be specified either with a numerical
-user identifier or with a user name. If a group is
-specified, the bus's owner-group will be set to that group,
-otherwise the group will remain unchanged (not changed
-to the group of the new owner.) The group can be specified
-either with a numerical group identifier or with a group
-name.
-
-The current ownership of the bus can be retrieved by
-running @command{stat} over the file @var{PATHNAME}.
-
-
-
-@node bus chgrp
-@section @command{bus chgrp}
-
-The syntax for invocation of @command{bus chgrp} is
-@example
-bus chgrp [--] @var{GROUP} @var{PATHNAME}
-@end example
-
-This command changes the group, that owns the bus whose
-key is stored in the file @var{PATHNAME}, to the specified
-group. The group can be specified either with a numerical
-group identifier or with a group name.
-
-The current ownership of the bus can be retrieved by
-running @command{stat} over the file @var{PATHNAME}.
-
-
-
-@node Interface
-@chapter Interface
-
-To use @command{libbus} in your C program, include the
-header file @file{<bus.h>} and link with the flag
-@option{-lbus}.
-
-With exception to @code{bus_poll} and @code{bus_poll_timed},
-all functions return @code{0} upon successful completion,
-and @code{-1} in case of failure. @code{bus_poll} and
-@code{bus_poll_timed} return @code{NULL} on failure.
-On failure on all functions set @code{errno} to indicate
-what went wrong.
-
-@file{<bus.h>} defines the following functions:
-
-@table @code
-@item int bus_create(const char *file, int flags, char **out_file)
-This function creates a bus with the asscoiated pathname
-specifed by the value of the parameter @code{file}. If
-@code{file} is @code{NULL} a random pathname is selected.
-This pathname adheres to the convention set forth by
-in @ref{Standard}.
-
-If @code{file} is not @code{NULL} the function fails if the
-file already exists if @code{flags} contains @code{BUS_EXCL}.
-Otherwise if @code{file} is not @code{NULL}, the function
-does nothing if the file already exists.
-
-If @code{flags} contains @code{BUS_INTR}, the function fails
-if it is interrupted.
-
-Unless @code{out_file} is NULL, the pathname of the bus
-should be stored in a new char array stored in @code{*out_file}.
-The caller must free the allocated stored in @code{*out_file}.
-
-If the processes cannot allocate enough memory to perform
-the action, the function sets @code{errno} to @code{ENOMEM}
-and fails. It may also fail and set @code{errno} to any of
-the errors specified for the system calls @code{open} and
-@code{write}.
-
-@item int bus_unlink(const char *file)
-This function removes the bus assoicated with the pathname
-stored in the parameter @code{file}. The function also
-unlinks the file.
-
-The function may set @code{errno} to any of the following
-values and fail for the specified reasons:
-@table @code
-@item EINVAL
-The bus does not exist.
-@item EACCES
-Operation permission is denied to the calling process.
-@item EPERM
-The user does not have permission to remove the bus.
-@end table
-@noindent
-It may also fail and set @code{errno} to any of the errors
-specified for the system calls @code{unlink} and @code{open},
-and the functions @code{semget} and @code{shmget}.
-
-@item int bus_open(bus_t *bus, const char *file, int flags)
-This function acquires resources required for the process
-to use the bus associated with the filename stored in the
-parameter @code{file}. The function also stores the resources
-in @code{bus} for use by other @command{bus} functions.
-
-Values for @code{flags} are constructed by a bitwise
-inclusive @sc{or} of flags from the following list.
-@table @code
-@item BUS_RDONLY
-The process will only be using the bus for receiving messages.
-@item BUS_WRONLY
-The process will only be using the bus for sending messages.
-@item BUS_RDWR
-The process will use the bus for both receiving and sending
-messages.
-@end table
-
-The function may set @code{errno} to any of the following
-values and fail for the specified reasons:
-@table @code
-@item ENOMEM
-The process cannot allocate enough memory to perform the
-action.
-@item EACCES
-Operation permission is denied to the calling process.
-@item EINVAL
-The described bus does not exist.
-@end table
-@noindent
-It may also fail and set @code{errno} to any of the errors
-specified for the system call @code{open}.
-
-@item int bus_close(bus_t *bus)
-This function disposes of resources allocated to the
-process, as referenced in the parameter @code{bus}.
-
-The function fails and sets @code{errno} to @code{EINVAL}
-if the bus does not exist.
-
-@item int bus_write(const bus_t *bus, const char *message, int flags)
-This function broadcasts a message on the bus whose
-information is stored in the parameter @code{bus}. The
-message read by the function is stored in the parameter
-@code{message}. It may not exceeed 2048 bytes, including
-NUL termination.
-
-The function shall fail, and set @code{errno} to
-@code{EAGAIN}, if the call would suspend the process and
-@code{flags} contains @code{BUS_NOWAIT}.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the function @code{semop}.
-
-@item int bus_write_timed(const bus_t *bus, const char *message, const struct timespec *timeout, clockid_t clockid)
-This function behaves like @code{bus_write}, except if it
-is not able to write the message within the specified time,
-it will fail and set @code{errno} to @code{EAGAIN}. The
-time is specified as an absolute time using the parameter
-@code{timeout}. The behaviour is unspecified if @code{timeout}
-is @code{NULL}. @code{timeout} is measured with the clock whose
-identifier is specified by the parameter @code{clockid}. This
-clock must be a predicitable clock@footnote{There are probably
-other, undocumented, seemingly arbitrary restrictions too.}.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the functions @code{semop} and
-@code{clock_gettime}.
-
-@item int bus_read(const bus_t *bus, int (*callback)(const char *message, void *user_data), void *user_data)
-This function waits for new message to be sent on the bus
-specified in the @code{bus} parameter, as provieded by a
-previous call to the function @code{bus_open}. Once a
-message is received, the parameter-function @code{callback}
-is invoked. The parameter @code{message} in @code{callback}
-is the received message, and @code{user_data} in
-@code{callback} should be @code{user_data} from @code{bus_read}.
-However, once the function [@code{bus_read}] has ensured
-that it will receive any message sent on the bus, it shall
-invoke the parameter-function @code{callback} with
-@code{message} set to @code{NULL}, to notify the process that
-it can perform any action that requires that it is listening
-on the bus.
-
-After @code{callback} returns, @code{message} may be override.
-Therefore @code{callback} should copy message and start a new
-thread that uses the copy of @code{message}. @code{callback}
-shall return @code{-1} on failure, @code{0} if the function
-[@code{bus_read}] should stop listening, or @code{1} if
-the function should continue listening.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the function @code{semop}.
-
-@item int bus_read_timed(const bus_t *bus, int (*callback)(const char *message, void *user_data), void *user_data, const struct timespec *timeout, clockid_t clockid)
-This function behaves like @code{bus_read}, except it will
-automatically fail and set @code{errno} to @code{EAGAIN} when
-the specified time has passed. The time is specified as an
-absolute time using the parameter @code{timeout}. The
-behaviour is unspecified if @code{timeout} is @code{NULL}.
-@code{timeout} is measured with the clock whose identifier
-is specified by the parameter @code{clockid}. This clock
-must be a predicitable clock@footnote{There are probably
-other, undocumented, seemingly arbitrary restrictions too.}.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the functions @code{semop} and
-@code{clock_gettime}.
-
-@item int bus_poll_start(bus_t *bus)
-@itemx int bus_poll_stop(const bus_t *bus)
-@itemx const char *bus_poll(bus_t *bus, int flags)
-@itemx const char *bus_poll_timed(bus_t *bus, const struct timespec *timeout, clockid_t clockid)
-The function @code{bus_poll} waits for a message to be
-broadcasted on the bus, and return the message it receives.
-The function fails if @code{flags} contains @code{BUS_NOWAIT}
-and there is not already a message waiting on the bus.
-Received messages shall be copied and parsed, and acted
-upon, in a separate thread, and the function @code{bus_poll}
-or the function @code{bus_poll_stop} called again as soon
-as possible.
-
-The funcion @code{bus_poll_start} must be called before
-@code{bus_poll} is called for the first time. When the
-process is done listening on the bus, it must call the
-function @code{bus_poll_stop}.
-
-The function @code{bus_poll_timed} behaves like the function
-@code{bus_poll}, except if it is not able to read a message
-within the specified time, it will fail and set @code{errno}
-to @code{EAGAIN}. The time is specified as an absolute time
-using the parameter @code{timeout}. The behaviour is
-unspecified if @code{timeout} is @code{NULL}. @code{timeout}
-is measured with the clock whose identifier is specified by
-the parameter @code{clockid}. This clock must be a predicitable
-clock@footnote{There are probably other, undocumented,
-seemingly arbitrary restrictions too.}.
-
-Upon successful completion, the functions @code{bus_poll} and
-@code{bus_poll_timed} returns the received message.
-
-These functions may fail and set @code{errno} to any of the
-errors specified for the function @code{semop}. The function
-@code{bus_poll_timed} may also set @code{errno} to any of
-the errors specified for @code{clock_gettime}.
-
-@item int bus_chown(const char *file, uid_t owner, gid_t group)
-This function changes the owner and the group of the bus,
-associated with the file whose pathname is stored in the
-parameter @code{file}, to the owner and group specified by
-the parameters @code{owner} and @code{group}, respectively.
-
-The current ownership of a bus can be retrieved by calling
-@code{stat} over the pathname of the bus.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the functions @code{bus_open},
-@code{chown}, @code{semget}, @code{shmget}, and @code{shmctl}
-as well as any errors specified for the commands
-@code{IPC_STAT} and @code{IPC_SET} for the function
-@code{semctl}.
-
-@item int bus_chmod(const char *file, mode_t mode)
-This function gives access to the bus associated with the
-file whose pathname is stored in the parameter @code{file}
-according to the following rules:
-
-@itemize @bullet{}
-@item
-If @code{mode} contains any of the bits @code{S_IRWXU}
-contains, the owner should be given full access to the
-bus. Otherwise the owner should have no access.
-@item
-If @code{mode} contains any of the bits @code{S_IRWXG}
-contains, the group should be given read and write
-access to the bus. Otherwise the group should have no
-access.
-@item
-If @code{mode} contains any of the bits @code{S_IRWXO}
-contains, users that are neither the owner nor member
-of the group should be given read and write access to
-the bus. Otherwise they should have no access.
-@end itemize
-
-The current permissions of a bus can be retrieved by calling
-@code{stat} over the pathname of the bus.
-
-The function may fail and set @code{errno} to any of the
-errors specified for the functions @code{bus_open},
-@code{chmode}, @code{semget}, @code{shmget}, and @code{shmctl}
-as well as any errors specified for the commands
-@code{IPC_STAT} and @code{IPC_SET} for the function
-@code{semctl}.
-@end table
-
-There is not reason for poking around in @code{bus_t}
-(@code{struct bus}). It should be considered opaque.
-You can read the documentation in @file{<bus.h>} if
-you want to know what is in it.
-
-
-
-
-@node Protocol
-@chapter Protocol
-
-@command{bus} is built upon following three procedures.
-
-@noindent
-@code{create}
-@example
-@w{@xrm{}Select a filename.@xtt{}}
-
-@w{@xrm{}Create XSI semaphore array @{@code{S} = 0, @code{W} = 0, @code{X} = 1, @code{Q} = 0, @code{N} = 0@}@xtt{}}
-@w{@xrm{}with random key. Store the semaphore array's key in decimal form@xtt{}}
-@w{@xrm{}on the first line in the selected file.@xtt{}}
-
-@w{@xrm{}Create XSI shared memory, with an allocation of 2048 bytes, with@xtt{}}
-@w{@xrm{}a random key. Store the shared memory's key in decimal form on@xtt{}}
-@w{@xrm{}the second line in the selected file.@xtt{}}
-@end example
-
-@noindent
-@code{broadcast}
-@example
-with P(X):
-  Z(W)
-  @w{@xrm{}Write NUL-terminate message to shared memory@xtt{}}
-  with V(N): -- (1)
-    Q := 0
-    Z(S)
-
--- (1) @w{@xrm{}may be omitted if semaphores are known that@xtt{}}
-   @w{P()@xrm{}, @xtt{}Z()@xrm{}, @xtt{}V()@xrm{} cannot create a race condition@xtt{}}
-   @w{@xrm{}with a processes running @xtt{}Z()@xrm{}.@xtt{}}
-@end example
-
-@noindent
-@code{listen}
-@example
-with V(S):
-  forever:
-    V(Q)
-    Z(Q)
-    @w{@xrm{}Read NUL-terminated message from shared memory@xtt{}}
-    if breaking:
-      break
-    with V(W):
-      with P(S):
-        Z(S)
-        Z(N)
-@end example
-
-@noindent
-@code{V(a)} means that semaphore a is released.@*
-@code{P(a)} means that semaphore a is acquired.@*
-@code{Z(a)} means that the process waits for semaphore a to become 0.@*
-@code{with P(a)} that @code{P(a)} is done before the entering the scope,
-and @code{V(a)} is done when exiting the scope. It also means that
-these actions [@code{P(a)} and @code{V(a)}] are undone when the process
-exits, or if the call fails.@*
-@code{with V(a)} is to @code{V(a)} as @code{with P(a)} is to @code{P(a)}.
-
-
-
-@node Rationale
-@chapter Rationale
-
-We need an interprocess communication system similar
-to message queues. But we need broadcasting rather than
-anycasting, so we have a fast, simple and daemonless
-system for announcing events to any processes that
-might be interested.
-
-
-
-@node Examples
-@chapter Examples
-
-This chapter contains usecase examples and
-API-demonstrations. You will find that they are (on
-a standard installation) installed on your system.
-
-@menu
-* Audio-volume control::
-* Telephony and music::
-* Timed::
-* Nonblocking::
-* Daemon-dependencies::
-@end menu
-
-
-
-
-@node Audio-volume control
-@section Audio-volume control
-
-Assume you have program that display the audio volume.
-This program checks every second third if the volume
-have changed.
-
-Also assume that you use @command{amixer} to change the
-volume, most often by using keybindings via @command{xbindkeys}.
-
-To reduce the delay, you want to send a signal to the
-monitor program that the volume have changed. For this
-more primitive IPC is sufficient, but lets assume there
-are other programs interested in this information too.
-
-To accomplish this, you create a wrapper for @command{amixer}
-that broadcasts updates on a bus. This wrapper is
-installed as @command{~/.local/bin/amixer}, and
-@command{~/.local/bin/} is included in @env{$PATH}
-before @command{/usr/bin}.
-@*
-
-@noindent
-Before starting run @command{./init}, this code is
-should be run from your profile file if you want to
-implement this on your system. After running
-@command{./init}, you can start one or more listeners
-by running @command{./alsa-monitor}.
-
-To change the volume run
-@code{./amixer -c 0 -- set Master 5%+} or similar.
-
-When you are done run @command{./cleanup}.
-
-
-@subsubheading @file{./amixer}
-@example
-#!/bin/sh
-/usr/bin/amixer "$@@"
-for arg in "$@@"; do
-  if [ "$@{arg@}" = "set" ]  || \
-     [ "$@{arg@}" = "sset" ] || \
-     [ "$@{arg@}" = "cset" ]; then
-    exec bus broadcast "/tmp/example-bus" '0 volume-changed *'
-  fi
-done
-@end example
-
-
-@subsubheading @file{./cleanup}
-@example
-#!/bin/sh
-exec bus remove "/tmp/example-bus"
-@end example
-
-
-@subsubheading @file{./init}
-@example
-#!/bin/sh
-bus create "/tmp/example-bus"
-
-# @w{@xrm{}The following code is more suitable in the real world,@xtt{}}
-# @w{@xrm{}if used, the other files should use @xtt{}"$@{BUS_AUDIO@}"}
-# @w{@xrm{}instead of @xtt{}"/tmp/example-bus"@xrm{}.@xtt{}}
-# 
-# export BUS_AUDIO="$@{XDG_RUNTIME_DIR@}/bus/audio"
-# if [ ! -f "$@{BUS_AUDIO@}" ]; then
-#   bus create "$@{BUS_AUDIO@}"
-# fi
-@end example
-
-
-@subsubheading @file{./monitor}
-@example
-#!/bin/sh
-if [ $# = 1 ]; then
-  if [ "$(echo "$@{1@}" | cut -d ' ' -f 2)" = "volume-changed" ]; then
-    printf '\e[H\e[2J'
-    amixer get Master
-  fi
-  exit 0
-fi
-
-exec 2>/dev/null
-
-printf '\e[?1049h\e[H\e[2J'
-trap -- "printf '\e[?1049l'" SIGINT
-bus listen "/tmp/example-bus" \'"$@{0/\'/\'\\\'\'@}"\'' "$@{msg@}"'
-@end example
-
-
-
-@node Telephony and music
-@section Telephony and music
-
-Assume you have a music player and a telephony program.
-You might like it if the music player pauses whenever
-you make or receive a call. You may also like it, if
-the music resumed when the call ended.
-
-In this example we will assume you the have @command{mocp}
-(@command{moc} package) running. And we will use the shell to
-simulate a telephony program.
-@*
-
-@noindent
-First of, run make to build this example. Before
-starting run @command{./init}. And when you are
-done run @command{./cleanup}.
-
-In one terminal run @command{./monitor}. This program
-will pause @command{mocp} when you make or receive a call,
-it will also resume @command{mocp} when all calls have
-ended if it did pause @command{mocp}.
-
-Then start any positive number of terminals.
-We will pretend that each of them are telephony
-programs. To make or receive a call, run
-@command{./receive-or-make-call}, when you want to
-end the pretend call, run @command{./end-call} from
-the terminal (or more accurately, from the same
-process.)
-
-
-@subsubheading @file{./Makefile}
-@example
-COMMANDS = init cleanup monitor end-call receive-or-make-call
-
-all: $@{COMMANDS@}
-%: %.c
-        $@{CC@} -Wall -Wextra -pedantic -std=c99 -lbus -o $@@ $<
-clean:
-        -rm $@{COMMANDS@}
-
-.PHONY: all clean
-@end example
-
-
-@subsubheading @file{./cleanup.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_unlink("/tmp/example-bus") && (perror("cleanup"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./end-call.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <stdint.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char message[BUS_MEMORY_SIZE];
-
-int main()
-@{
-  bus_t bus;
-  sprintf(message, "%ji unforce-pause", (intmax_t)getppid());
-  /* @w{@xrm{}Yes, PPID; in this example we pretend the shell is the telephony process.@xtt{}} */
-  t (bus_open(&bus, "/tmp/example-bus", BUS_WRONLY));
-  t (bus_write(&bus, message, 0));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("end-call");
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./init.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_create("/tmp/example-bus", 0, NULL) && (perror("init"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./monitor.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-static size_t pauser_count = 0;
-static size_t pausers_size = 0;
-static char* pausers = NULL;
-
-static int is_moc_playing(void)
-@{
-  return !WEXITSTATUS(system("env LANG=C mocp -i 2>/dev/null |"
-                             "grep 'State: PLAY' >/dev/null"));
-@}
-
-/* @w{@xrm{}In a proper implementation, message whould be copyied, and then@xtt{}}
- * @w{@xrm{}a new thread would be created that parsed the copy. But that is@xtt{}}
- * @w{@xrm{}too much for an example, especially since it would also require@xtt{}}
- * @w{@xrm{}a mutex to make sure two threads do not modify data at the same@xtt{}}
- * @w{@xrm{}time, causing chaos.@xtt{}} */
-static int callback(const char *message, void *user_data)
-@{
-  char *msg = NULL;
-  size_t len = 0;
-  if (message == 0)
-    return 1;
-  while ((len < 2047) && message[len])
-    len++;
-  msg = malloc((len + 1) * sizeof(char));
-  t (msg == NULL);
-  memcpy(msg, message, len * sizeof(char));
-  msg[len] = 0;
-  /* @w{@xrm{}BEGIN run as in a separate thread@xtt{}} */
-  if (pauser_count || is_moc_playing()) @{
-    char *begin = strchr(msg, ' ');
-    ssize_t pid;
-    int requests_pause;
-    if (begin == NULL)
-      goto done;
-    *begin++ = 0;
-    pid = (ssize_t)atoll(msg);
-    if (pid < 1) /* @w{@xrm{}We need a real PID, too bad there is@xtt{}}
-                  * @w{@xrm{}no convient way to detect if it dies.@xtt{}} */
-      goto done;
-    if ((strstr(begin, "force-pause ") == begin) ||
-        !strcmp(begin, "force-pause"))
-      requests_pause = 1;
-    else if ((strstr(begin, "unforce-pause ") == begin) ||
-             !strcmp(begin, "unforce-pause"))
-      requests_pause = 0;
-    else
-      goto done;
-    if ((size_t)pid >= pausers_size) @{
-      pausers = realloc(pausers, (size_t)(pid + 1) * sizeof(char));
-      t (pausers == NULL); /* @w{@xrm{}Let's ignore the memory leak.@xtt{}} */
-      memset(pausers + pausers_size, 0,
-             ((size_t)(pid + 1) - pausers_size) * sizeof(char));
-      pausers_size = (size_t)(pid + 1);
-    @}
-    if (pausers[pid] ^ requests_pause) @{
-      pauser_count += requests_pause ? 1 : -1;
-      pausers[pid] = requests_pause;
-      if (pauser_count == (size_t)requests_pause)
-        system(requests_pause ? "mocp -P" : "mocp -U");
-    @}
-  @}
-  /* @w{@xrm{}END run as in a separate thread@xtt{}} */
-  goto done;
-  (void) user_data;
-
-fail:
-  perror("monitor");
-  return -1;
-
-done:
-  free(msg);
-  return 1;
-@}
-
-int main()
-@{
-  bus_t bus;
-  t (bus_open(&bus, "/tmp/example-bus", BUS_RDONLY));
-  t (bus_read(&bus, callback, NULL));
-  bus_close(&bus);
-  free(pausers);
-  return 0;
-
-fail:
-  perror("monitor");
-  bus_close(&bus);
-  free(pausers);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./receive-or-make-call.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <stdint.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char message[BUS_MEMORY_SIZE];
-
-int main()
-@{
-  bus_t bus;
-  sprintf(message, "%ji force-pause", (intmax_t)getppid());
-  /* @w{@xrm{}Yes, PPID; in this example we pretend the shell is the telephony process.@xtt{}} */
-  t (bus_open(&bus, "/tmp/example-bus", BUS_WRONLY));
-  t (bus_write(&bus, message, 0));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("receive-or-make-call");
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-
-@node Timed
-@section Timed
-
-This example shows how to use timed operations.
-
-First of, run make to build this example.
-
-To start the example run @command{./init}. When you are
-done run @command{./cleanup}.
-
-Running instances of @command{./poll} will wait for new
-messages continuously, but with one second timeouts.
-
-@command{./slow-poll} works like @command{./poll}, except
-it will sleep for one second every time it receives
-a message.
-
-Running instances of @command{./read} will read for ten
-seconds and then time out.
-
-@command{./poll}, @command{./read}, and @command{./slow-poll}
-will stop if the message "stop" is broadcasted.
-
-@command{./write} will wait for atmost a tenth of a
-seconds before failing. This means that if two instances
-of @command{./write} is started at the same time one of
-them will fail if @command{./slow-poll} is running.
-
-@command{./poll}, @command{./read}, @command{./init} and
-@command{./cleanup} are run without any additional
-arguments. @command{./write} is run with the message
-as the second argument.
-
-
-@subsubheading @file{./Makefile}
-@example
-COMMANDS = init cleanup write poll read slow-poll
-
-all: $@{COMMANDS@}
-%: %.c
-        $@{CC@} -Wall -Wextra -pedantic -std=c99 -lbus -o $@@ $<
-clean:
-        -rm $@{COMMANDS@}
-
-.PHONY: all clean
-@end example
-
-
-@subsubheading @file{./cleanup.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_unlink("/tmp/example-bus") && (perror("cleanup"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./init.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_create("/tmp/example-bus", 0, NULL) && (perror("init"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./poll.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-int main()
-@{
-  bus_t bus;
-  const char *message;
-  long long tick = 0;
-  struct timespec timeout;
-  t (bus_open(&bus, "/tmp/example-bus", BUS_RDONLY));
-  t (bus_poll_start(&bus));
-  for (;;) @{
-    t (clock_gettime(CLOCK_MONOTONIC, &timeout));
-    timeout.tv_sec += 1;
-    message = bus_poll_timed(&bus, &timeout, CLOCK_MONOTONIC);
-    if (message == NULL) @{
-      t (errno != EAGAIN);
-      printf("waiting... %lli\n", ++tick);
-      continue;
-    @}
-    tick = 0;
-    message = strchr(message, ' ') + 1;
-    if (!strcmp(message, "stop"))
-      break;
-    printf("\033[01m%s\033[21m\n", message);
-  @}
-  t (bus_poll_stop(&bus));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("poll");
-  bus_poll_stop(&bus);
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./read.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static int callback(const char *message, void *user_data)
-@{
-  (void) user_data;
-
-  if (message == NULL)
-    return 1;
-
-  message = strchr(message, ' ') + 1;
-  if (!strcmp(message, "stop"))
-    return 0;
-  printf("%s\n", message);
-  return 1;
-@}
-
-int main()
-@{
-  bus_t bus;
-  struct timespec timeout;
-  t (bus_open(&bus, "/tmp/example-bus", BUS_RDONLY));
-  t (clock_gettime(CLOCK_MONOTONIC, &timeout));
-  timeout.tv_sec += 10;
-  t (bus_read_timed(&bus, callback, NULL, &timeout, CLOCK_MONOTONIC));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("poll");
-  bus_poll_stop(&bus);
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./slow-poll.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-int main()
-@{
-  bus_t bus;
-  const char *message;
-  long long tick = 0;
-  struct timespec timeout;
-  t (bus_open(&bus, "/tmp/example-bus", BUS_RDONLY));
-  t (bus_poll_start(&bus));
-  for (;;) @{
-    t (clock_gettime(CLOCK_MONOTONIC, &timeout));
-    timeout.tv_sec += 1;
-    message = bus_poll_timed(&bus, &timeout, CLOCK_MONOTONIC);
-    if (message == NULL) @{
-      t (errno != EAGAIN);
-      printf("waiting... %lli\n", ++tick);
-      continue;
-    @}
-    tick = 0;
-    message = strchr(message, ' ') + 1;
-    if (!strcmp(message, "stop"))
-      break;
-    printf("\033[01m%s\033[21m\n", message);
-    sleep(1);
-  @}
-  t (bus_poll_stop(&bus));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("poll");
-  bus_poll_stop(&bus);
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./write.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <stdint.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char message[BUS_MEMORY_SIZE];
-
-int main(int argc, char *argv[])
-@{
-  bus_t bus;
-  struct timespec timeout;
-  if (argc < 2) @{
-    fprintf(stderr, "%s: USAGE: %s message\n", argv[0], argv[0]);
-    return 2;
-  @}
-  sprintf(message, "0 %s", argv[1]);
-  t (bus_open(&bus, "/tmp/example-bus", BUS_WRONLY));
-  t (clock_gettime(CLOCK_MONOTONIC, &timeout));
-  timeout.tv_nsec += 100000000L;
-  t (bus_write_timed(&bus, message, &timeout, CLOCK_MONOTONIC));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("write");
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-
-@node Nonblocking
-@section Nonblocking
-
-This example shows how to use bus_poll instead of bus_read,
-and how to do non-blocking polling and non-blocking writing.
-
-First of, run make to build this example.
-
-To start the example run @command{./init}. When you are done
-run @command{./cleanup}.
-
-Running instances of @command{./poll} will check every second
-if there is a new inbound message. Between these checks
-@command{./write} will wait for all @command{./poll}:s to
-receive the message. This means that @command{./write} blocks
-while @command{./poll} sleeps. If two or more instances of
-@command{./write} is started at approximately the same time,
-only one will continue to write a message on the bus, the
-others will fail.
-
-@command{./poll} will stop if the message ``stop'' is
-broadcasted.
-
-@command{./poll}, @command{./init} and @command{./cleanup}
-are run without any additional arguments. @command{./write}
-is run with the message as the second argument.
-
-
-@subsubheading @file{./Makefile}
-@example
-COMMANDS = init cleanup write poll
-
-all: $@{COMMANDS@}
-%: %.c
-        $@{CC@} -Wall -Wextra -pedantic -std=c99 -lbus -o $@@ $<
-clean:
-        -rm $@{COMMANDS@}
-
-.PHONY: all clean
-@end example
-
-
-@subsubheading @file{./cleanup.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_unlink("/tmp/example-bus") && (perror("cleanup"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./init.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-
-int main()
-@{
-  return bus_create("/tmp/example-bus", 0, NULL) && (perror("init"), 1);
-@}
-@end example
-
-
-@subsubheading @file{./poll.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-int main()
-@{
-  bus_t bus;
-  const char *message;
-  long long tick = 0;
-  t (bus_open(&bus, "/tmp/example-bus", BUS_RDONLY));
-  t (bus_poll_start(&bus));
-  for (;;) @{
-    message = bus_poll(&bus, BUS_NOWAIT);
-    if (message == NULL) @{
-      t (errno != EAGAIN);
-      printf("waiting... %lli\n", ++tick);
-      sleep(1);
-      continue;
-    @}
-    tick = 0;
-    message = strchr(message, ' ') + 1;
-    if (!strcmp(message, "stop"))
-      break;
-    printf("\033[01m%s\033[21m\n", message);
-  @}
-  t (bus_poll_stop(&bus));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("poll");
-  bus_poll_stop(&bus);
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./write.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <stdint.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char message[BUS_MEMORY_SIZE];
-
-int main(int argc, char *argv[])
-@{
-  bus_t bus;
-  if (argc < 2) @{
-    fprintf(stderr, "%s: USAGE: %s message\n", argv[0], argv[0]);
-    return 2;
-  @}
-  sprintf(message, "0 %s", argv[1]);
-  t (bus_open(&bus, "/tmp/example-bus", BUS_WRONLY));
-  t (bus_write(&bus, message, BUS_NOWAIT));
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("write");
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-
-@node Daemon-dependencies
-@section Daemon-dependencies
-
-This example shows how bus can be used in an init system
-to provide ``aggressivly'' parallel startup of daemons.
-
-First of, run make to build this example.
-
-To start the example run @command{./init}. It will print in
-red export-statement you may want to run i other terminals.
-You will need to select at least one daemon, for example
-you can run @code{./init d-ntp}. The available pretend
-daemons are: @command{d-network}, @command{d-ntp}, and
-@command{d-ssh}.
-
-When you are done run @command{./cleanup} with @env{BUS_INIT}
-exported with the value printed by @command{./init}.
-
-
-@subsubheading @file{./Makefile}
-@example
-COMMANDS = announce await-ready await-started cleanup  \
-           init require start-daemon test-daemon
-
-all: $@{COMMANDS@}
-%: %.c
-        $@{CC@} -Wall -Wextra -pedantic -std=c99 -lbus -o $@@ $<
-clean:
-        -rm $@{COMMANDS@}
-        -rm -r run
-
-.PHONY: all clean
-@end example
-
-
-@subsubheading @file{./announce.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char arg[4098];
-
-int main(int argc, char *argv[])
-@{
-  bus_t bus;
-  if (argc < 3)
-    return fprintf(stderr, "USAGE: %s state daemon", *argv), 2;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
-  sprintf(arg, "%ji %s %s", (intmax_t)getppid(), argv[1], argv[2]);
-  t (bus_write(&bus, arg, 0));
-  t (bus_close(&bus));
-  return 0;
-
-fail:
-  perror("announce");
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./await-ready.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <string.h>
-#include <sys/wait.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char arg[4098];
-static int argc;
-static char **argv;
-static int remaining = 0;
-static char *started = NULL;
-static char msg[BUS_MEMORY_SIZE];
-
-static void announce_wait(pid_t pid)
-@{
-  bus_t bus;
-  int i;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
-  for (i = 1; i < argc; i++) @{
-    if (!started[i]) @{
-      sprintf(arg, "%ji awaiting-ready %s", (intmax_t)pid, argv[i]);
-      t (bus_write(&bus, arg, 0));
-    @}
-  @}
-  t (bus_close(&bus));
-  return;
-
-fail:
-  perror("await-ready");
-@}
-
-static int callback(const char *message, void *user_data)
-@{
-  int i;
-  char *arg2;
-  char *arg3;
-  pid_t pid;
-  pid_t ppid;
-
-  if (!message) @{
-    ppid = getppid();
-    pid = fork();
-    if (pid == 0) @{
-      if (fork() == 0)
-        announce_wait(ppid);
-      exit(0);
-    @} else @{
-      (void) waitpid(pid, NULL, 0);
-      /* @w{@xrm{}Let's pretend everything will go swimmingly.@xtt{}} */
-    @}
-    return 1;
-  @}
-
-  strncpy(msg, message, BUS_MEMORY_SIZE - 1);
-  msg[BUS_MEMORY_SIZE - 1] = 0;
-
-  arg2 = strchr(msg, ' ');
-  if (!arg2)
-    return 1;
-  arg3 = strchr(++arg2, ' ');
-  if (!arg3)
-    return 1;
-  *arg3++ = 0;
-
-  if (strcmp(arg2, "ready"))
-    return 1;
-
-  for (i = 1; i < argc; i++)
-    if (!started[i] && !strcmp(argv[i], arg3))
-      started[i] = 1, remaining--;
-
-  return !!remaining;
-  (void) user_data;
-@}
-
-int main(int argc_, char *argv_[])
-@{
-  bus_t bus;
-  int i;
-
-  argc = argc_;
-  argv = argv_;
-
-  if (argc < 2)
-    return fprintf(stderr, "USAGE: %s daemon...", *argv), 2;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_RDONLY));
-  started = calloc(argc, sizeof(char));
-  t (started == NULL);
-
-  started[0] = 1;
-  for (i = 1; i < argc; i++) @{
-    sprintf(arg, "grep '^%s$'"
-                 " <\"$@{XDG_RUNTIME_DIR@}/ready-daemons\""
-                 " >/dev/null",
-            argv[i]);
-    if (!WEXITSTATUS(system(arg)))
-      started[i] = 1;
-    else
-      remaining++;
-  @}
-
-  if (remaining)
-    bus_read(&bus, callback, NULL);
-
-  bus_close(&bus);
-  free(started);
-  return 0;
-
-fail:
-  perror("await-ready");
-  bus_close(&bus);
-  free(started);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./await-started.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <string.h>
-#include <sys/wait.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char arg[4098];
-static int argc;
-static char **argv;
-static int remaining = 0;
-static char *started = NULL;
-static char msg[BUS_MEMORY_SIZE];
-
-static void announce_wait(pid_t pid)
-@{
-  bus_t bus;
-  int i;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
-  for (i = 1; i < argc; i++) @{
-    if (!started[i]) @{
-      sprintf(arg, "%ji awaiting-started %s", (intmax_t)pid, argv[i]);
-      t (bus_write(&bus, arg, 0));
-    @}
-  @}
-  t (bus_close(&bus));
-  return;
-
-fail:
-  perror("await-started");
-@}
-
-static int callback(const char *message, void *user_data)
-@{
-  int i;
-  char *arg2;
-  char *arg3;
-  pid_t pid;
-  pid_t ppid;
-
-  if (!message) @{
-    ppid = getppid();
-    pid = fork();
-    if (pid == 0) @{
-      if (fork() == 0)
-        announce_wait(ppid);
-      exit(0);
-    @} else @{
-      (void) waitpid(pid, NULL, 0);
-      /* @w{@xrm{}Let's pretend everything will go swimmingly.@xtt{}} */
-    @}
-    return 1;
-  @}
-
-  strncpy(msg, message, BUS_MEMORY_SIZE - 1);
-  msg[BUS_MEMORY_SIZE - 1] = 0;
-
-  arg2 = strchr(msg, ' ');
-  if (!arg2)
-    return 1;
-  arg3 = strchr(++arg2, ' ');
-  if (!arg3)
-    return 1;
-  *arg3++ = 0;
-
-  if (strcmp(arg2, "started") && strcmp(arg2, "ready"))
-    return 1;
-
-  for (i = 1; i < argc; i++)
-    if (!started[i] && !strcmp(argv[i], arg3))
-      started[i] = 1, remaining--;
-
-  return !!remaining;
-  (void) user_data;
-@}
-
-int main(int argc_, char *argv_[])
-@{
-  bus_t bus;
-  int i;
-
-  argc = argc_;
-  argv = argv_;
-
-  if (argc < 2)
-    return fprintf(stderr, "USAGE: %s daemon...", *argv), 2;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_RDONLY));
-  started = calloc(argc, sizeof(char));
-  t (started == NULL);
-
-  started[0] = 1;
-  for (i = 1; i < argc; i++) @{
-    sprintf(arg, "grep '^%s$'"
-                 " <\"$@{XDG_RUNTIME_DIR@}/started-daemons\""
-                 " >/dev/null",
-            argv[i]);
-    if (!WEXITSTATUS(system(arg))) @{
-      started[i] = 1;
-    @} else @{
-      sprintf(arg, "grep '^%s$'"
-                   " <\"$@{XDG_RUNTIME_DIR@}/ready-daemons\""
-                   " >/dev/null",
-              argv[i]);
-      if (!WEXITSTATUS(system(arg)))
-        started[i] = 1;
-      else
-        remaining++;
-    @}
-  @}
-
-  if (remaining)
-    bus_read(&bus, callback, NULL);
-
-  bus_close(&bus);
-  free(started);
-  return 0;
-
-fail:
-  perror("await-started");
-  bus_close(&bus);
-  free(started);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./cleanup.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-int main()
-@{
-  char *bus_address = getenv("BUS_INIT");
-  if (!bus_address || !*bus_address) @{
-    fprintf(stderr, "$BUS_INIT has not been set, its export statement "
-                    "should have been printed in bold red by ./init\n");
-    return 1;
-  @}
-  t (bus_unlink(bus_address));
-  return 0;
-
-fail:
-  perror("cleanup");
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./d-network}
-@example
-#!/bin/sh
-PATH=.:$PATH
-d=d-network
-
-echo $d: starting
-sleep 2
-echo $d: ready
-announce ready $d
-@end example
-
-
-@subsubheading @file{./d-ntp}
-@example
-#!/bin/sh
-PATH=.:$PATH
-d=d-ntp
-
-require d-network
-echo $d: started
-announce started $d
-await-ready d-network
-echo $d: ready
-announce ready $d
-@end example
-
-
-@subsubheading @file{./d-ssh}
-@example
-#!/bin/sh
-PATH=.:$PATH
-d=d-ssh
-
-require d-network
-echo $d: starting
-sleep 1
-echo $d: started
-announce started $d
-sleep 1
-echo $d: ready
-announce ready $d
-@end example
-
-
-@subsubheading @file{./init.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/wait.h>
-
-#define t(stmt)  if (stmt) goto fail
-#define _2(...)  __VA_ARGS__, __VA_ARGS__
-
-static char msg[BUS_MEMORY_SIZE];
-static int argc;
-static char **argv;
-static char arg[4098];
-
-static void start_daemons()
-@{
-  int i;
-  for (i = 1; i < argc; i++)
-    if (fork() == 0)
-      execl("./start-daemon", "./start-daemon", argv[i], NULL); 
-@}
-
-static int callback(const char *message, void *user_data)
-@{
-  pid_t pid;
-  char *arg2;
-  char *arg3;
-  if (!message) @{
-    pid = fork();
-    t (pid == -1);
-    if (pid == 0) @{
-      if (fork() == 0) @{
-        start_daemons();
-      @}
-      exit(0);
-    @} else @{
-      (void) waitpid(pid, NULL, 0);
-      /* @w{@xrm{}Let's pretend everything will go swimmingly.@xtt{}} */
-    @}
-    return 1;
-  @}
-
-  strncpy(msg, message, BUS_MEMORY_SIZE - 1);
-  msg[BUS_MEMORY_SIZE - 1] = 0;
-
-  pid = fork();
-  t (pid == -1);
-
-  if (pid == 0) @{
-    if (fork() == 0) @{
-      arg2 = strchr(msg, ' ');
-      if (arg2 == NULL)
-        exit(0);
-      arg3 = strchr(++arg2, ' ');
-      if (arg3 == NULL)
-        exit(0);
-      *arg3++ = 0;
-      if (!strcmp(arg2, "require")) @{
-        execl(_2("./start-daemon"), arg3, NULL);
-      @} else if (!strcmp(arg2, "awaiting-started")) @{
-        execl(_2("./test-daemon"), arg3, "started", NULL);
-      @} else if (!strcmp(arg2, "awaiting-ready") ||
-                  !strcmp(arg2, "awaiting")) @{
-        execl(_2("./test-daemon"), arg3, "ready", NULL);
-      @} else if (!strcmp(arg2, "started")) @{
-        sprintf(arg,
-          "grep '^%s\\$' < \"%s\" >/dev/null || echo %s >> \"%s\"",
-          _2(arg3, "$@{XDG_RUNTIME_DIR@}/started-daemons"));
-        execlp(_2("sh"), "-c", arg, NULL);
-      @} else if (!strcmp(arg2, "ready")) @{
-        sprintf(arg,
-          "grep '^%s\\$' < \"%s\" >/dev/null || echo %s >> \"%s\"",
-          _2(arg3, "$@{XDG_RUNTIME_DIR@}/ready-daemons"));
-        execlp(_2("sh"), "-c", arg, NULL);
-      @}
-    @}
-    exit(0);
-  @} else @{
-    (void) waitpid(pid, NULL, 0);
-    /* @w{@xrm{}Let's pretend everything will go swimmingly.@xtt{}} */
-  @}
-
-  return 1;
-  (void) user_data;
-
-fail:
-  perror("init");
-  return -1;
-@}
-
-int main(int argc_, char *argv_[])
-@{
-  char *bus_address = NULL;
-  bus_t bus;
-  argv = argv_;
-  argc = argc_;
-  if (argc < 2) @{
-    fprintf(stderr, "USAGE: %s daemon...\n", *argv);
-    return 1;
-  @}
-  t (setenv("XDG_RUNTIME_DIR", "./run", 1));
-  /* @w{@xrm{}Real init systems with not have the period.@xtt{}} */
-  system("mkdir -p -- \"$@{XDG_RUNTIME_DIR@}\"");
-  system("truncate -s 0 -- \"$@{XDG_RUNTIME_DIR@}/started-daemons\"");
-  system("truncate -s 0 -- \"$@{XDG_RUNTIME_DIR@}/ready-daemons\"");
-  t (bus_create(NULL, 1, &bus_address));
-  fprintf(stderr, "\033[00;01;31mexport BUS_INIT=%s\033[00m\n",
-          bus_address);
-  fprintf(stderr, "\033[00;31mexport XDG_RUNTIME_DIR=./run\033[00m\n");
-  t (setenv("BUS_INIT", bus_address, 1));
-  t (bus_open(&bus, bus_address, BUS_RDONLY));
-  t (bus_read(&bus, callback, NULL));
-  bus_close(&bus);
-  free(bus_address);
-  return 0;
-
-fail:
-  perror("init");
-  bus_close(&bus);
-  free(bus_address);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./require.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char arg[4098];
-
-int main(int argc, char *argv[])
-@{
-  bus_t bus;
-  int i;
-  if (argc < 2)
-    return fprintf(stderr, "USAGE: %s daemon...", *argv), 2;
-  t (bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
-
-  for (i = 1; i < argc; i++) @{
-    sprintf(arg, "grep '^%s$' <\"%s\" >/dev/null",
-            argv[i], "$@{XDG_RUNTIME_DIR@}/started-daemons");
-    if (WEXITSTATUS(system(arg))) @{
-      sprintf(arg, "%ji require %s", (intmax_t)getppid(), argv[i]);
-      t (bus_write(&bus, arg, 0));
-    @}
-  @}
-
-  bus_close(&bus);
-  return 0;
-
-fail:
-  perror("require");
-  bus_close(&bus);
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./start-daemon.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-static char arg[4098];
-
-int main(int argc, char *argv[])
-@{
-  if (argc != 2) @{
-    fprintf(stderr, "This program should be called from ./init\n");
-    return 2;
-  @}
-
-  sprintf(arg, "grep '^%s$' <\"%s\" >/dev/null",
-          argv[1], "$@{XDG_RUNTIME_DIR@}/started-daemons");
-  if (!WEXITSTATUS(system(arg)))
-    return 0;
-  sprintf(arg, "grep '^%s$' <\"%s\" >/dev/null",
-          argv[1], "$@{XDG_RUNTIME_DIR@}/ready-daemons");
-  if (!WEXITSTATUS(system(arg)))
-    return 0;
-
-  sprintf(arg, "./%s", argv[1]);
-  execlp(arg, arg, NULL);
-  perror("start-daemon");
-  return 1;
-@}
-@end example
-
-
-@subsubheading @file{./test-daemon.c}
-@example
-#include <bus.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#define t(stmt)  if (stmt) goto fail
-
-static char arg[4098];
-
-int main(int argc, char *argv[])
-@{
-  bus_t bus;
-  if (argc != 3) @{
-    fprintf(stderr, "This program should be called from ./init\n");
-    return 2;
-  @}
-
-retry:
-  sprintf(arg, "grep '^%s$'"
-               " <\"$@{XDG_RUNTIME_DIR@}/%s-daemons\""
-               " >/dev/null",
-          argv[1], argv[2]);
-  if (!WEXITSTATUS(system(arg))) @{
-    t (bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
-    sprintf(arg, "0 %s %s", argv[2], argv[1]);
-    t (bus_write(&bus, arg, 0));
-    bus_close(&bus);
-  @} else if (!strcmp(argv[2], "started")) @{
-    argv[2] = "ready";
-    goto retry;
-  @}
-  return 0;
-
-fail:
-  perror("test-daemon");
-  return 1;
-@}
-@end example
-
-
-
-@node GNU Free Documentation License
-@appendix GNU Free Documentation License
-@include fdl.texinfo
-
-@bye
-
diff --git a/doc/info/fdl.texinfo b/doc/info/fdl.texinfo
deleted file mode 100644
index cb71f05..0000000
--- a/doc/info/fdl.texinfo
+++ /dev/null
@@ -1,505 +0,0 @@
-@c The 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
-ASCII without markup, Texinfo input format, La@TeX{} 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.
-
-@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
-
-@page
-@heading 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: