This is texinfo.info, produced by texi2any version 7.2 from
texinfo.texi.

This manual is for GNU Texinfo (version 7.2, 20 December 2024), a
documentation system that can produce both online information and a
printed manual from a single source using semantic markup.

   Copyright © 1988-2024 Free Software Foundation, Inc.

     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".
INFO-DIR-SECTION Texinfo documentation system
START-INFO-DIR-ENTRY
* Texinfo: (texinfo).           The GNU documentation format.
* install-info: (texinfo)Invoking install-info. Update info/dir entries.
* texi2any: (texinfo)Invoking texi2any.         Translate Texinfo source.
* makeinfo: (texinfo)Invoking texi2any.         Translate Texinfo source.
* pod2texi: (pod2texi)Invoking pod2texi.        Translate Perl Pod to Texinfo.
* texi2dvi: (texinfo)Format with texi2dvi.      Print Texinfo documents.
* texi2pdf: (texinfo)PDF Output.                PDF output for Texinfo.
* pdftexi2dvi: (texinfo)PDF Output.             PDF output for Texinfo.
* texindex: (texinfo)Format with tex/texindex.  Sort Texinfo index files.
END-INFO-DIR-ENTRY


File: texinfo.info,  Node: Top,  Next: Copying Conditions,  Up: (dir)

Texinfo
*******

This manual is for GNU Texinfo (version 7.2, 20 December 2024), a
documentation system that can produce both online information and a
printed manual from a single source using semantic markup.

   The first part of this master menu lists the major nodes in this Info
document, including the @-command and concept indices.  The rest of the
menu lists all the lower-level nodes in the document.

* Menu:

* Copying Conditions::         Your rights.
* Overview::                   Texinfo in brief.
* Writing a Texinfo File::     Format of a Texinfo source file.
* Nodes::                      Writing nodes, the basic unit of Texinfo.
* Chapter Structuring::        Creating chapters, sections, appendices, etc.
* Cross References::           Writing cross-references.
* Marking Text::               Marking words and phrases as code, keyboard
                               input, meta-syntactic variables, and the like.
* Quotations and Examples::    Block quotations, examples, etc.
* Lists and Tables::           Itemized or numbered lists, and tables.
* Special Displays::           Floating figures and footnotes.
* Indices::                    Creating indices.
* Insertions::                 Inserting @-signs, braces, etc.
* Breaks::                     Forcing or preventing line and page breaks.
* Definition Commands::        Describing functions and the like uniformly.
* Internationalization::       Supporting languages other than English.
* Conditionals::               Specifying text for only some output cases.
* Defining New Texinfo Commands::  User-defined macros and aliases.
* Include Files::              How to incorporate other Texinfo files.
* Hardcopy with TeX::          Output for paper, with TeX.
* Generic Translator texi2any::  ‘texi2any’, an all-purpose converter.
* Creating and Installing Info Files::  Details on Info output.
* Generating HTML::            Details on HTML output.

Appendices

* @-Command Details::          Details of the Texinfo @-commands.
* Tips::                       Hints on how to write a Texinfo document.
* Sample Texinfo Files::       Complete examples, including full texts.
* Texinfo Mode::               Using the GNU Emacs Texinfo mode.
* Global Document Commands::   Affecting formatting throughout.
* Info Format Specification::  Technical details of the Info file format.
* GNU Free Documentation License::  Copying this manual.
* Command Index::
* Variables Index::
* General Index::              A menu covering many topics.

 -- The Detailed Node Listing --

Overview of Texinfo

* Reporting Bugs::             Submitting effective bug reports.
* Output Formats::             Overview of the supported output formats.
* Info Files::                 What is an Info file?
* Printed Books::              Characteristics of a printed book or manual.
* Adding Output Formats::      Man pages and implementing new formats.
* History::                    Acknowledgements, contributors and genesis.

Writing a Texinfo File

* Conventions::                General rules for writing a Texinfo file.
* Comments::                   Writing comments and ignored text in general.
* Minimum::                    What a Texinfo file must have.
* Short Sample Texinfo File::  A short sample Texinfo file.
* Texinfo File Header::        The first lines.
* Directory Category::         A category for a manual.
* Document Permissions::       Ensuring your manual is free.
* Titlepage & Copyright Page:: Creating the title and copyright pages.
* Contents::                   How to create a table of contents.
* The Top Node::               Creating the 'Top' node and master menu.
* The Body of the Document::   The rest of the nodes.
* Ending a File::              What is at the end of a Texinfo file?

Texinfo File Header

* First Line::                 The first line of a Texinfo file.
* @setfilename::               Give the name of the output file.
* @settitle::                  Create a title for the printed work.
* Preamble::                   Start of the Texinfo file up to first content.
* Start and End of Header::    Formatting a region in Emacs requires this.

Document Permissions

* @copying::                   Declare the document's copying permissions.
* @insertcopying::             Where to insert the permissions.

Title and Copyright Pages

* @titlepage::                 Create a title for the printed document.
* @title @subtitle @author::   The ‘@title’, ‘@subtitle’, and ‘@author’
                               commands.
* @titlefont @center @sp::     The ‘@titlefont’, ‘@center’, and ‘@sp’ commands.
* Copyright::                  How to write the copyright notice and include
                               copying permissions.
* Heading Generation::         Turn on page headings after the title and
                               copyright pages.

The 'Top' Node and Master Menu

* Master Menu Parts::

Nodes

* Writing a Node::             How to write a ‘@node’ line.
* Node Names::                 How to choose node names.
* Node Line Requirements::     Keep names unique.
* First Node::                 How to write a 'Top' node.
* @top Command::               How to use the ‘@top’ command.
* Texinfo Document Structure:: Double structure of documents.
* Node Menu Illustration::     A diagram, and sample nodes and menus.
* Node Descriptions::          ‘@nodedescription’ and ‘@nodedescriptionblock’.
* Menus::                      Listing subordinate nodes.

Menus

* Writing a Menu::             What is a menu?
* Menu Example::               Two and three part menu entries.
* Menu Location::              Menus go at the ends of nodes.
* Menu Parts::                 A menu entry has three parts.
* Less Cluttered Menu Entry::  Two part menu entry.
* Other Info Files::           How to refer to a different Info file.

Chapter Structuring

* Tree Structuring::           A manual is like an upside down tree ...
* Structuring Command Types::
* @chapter::
* @unnumbered @appendix::
* @majorheading @chapheading::
* @section::
* @unnumberedsec @appendixsec @heading::
* @subsection::
* @unnumberedsubsec @appendixsubsec @subheading::
* @subsubsection::
* @part::                      Collections of chapters.
* Raise/lower sections::       How to change commands' hierarchical level.

Cross-references

* Cross Reference Commands::   A summary of the different commands.
* Cross Reference Parts::      A cross-reference has several parts.
* One Argument::               ‘@xref’ with one argument.
* Two Arguments::              ‘@xref’ with two arguments.
* Three Arguments::            ‘@xref’ with three arguments.
* Four and Five Arguments::    ‘@xref’ with four and five arguments.
* Referring to a Manual as a Whole::  Refer to an entire manual.
* @xref::                      Begin a reference with 'See' ...
* @ref::                       A reference for the last part of a sentence.
* @pxref::                     How to write a parenthetical cross-reference.
* @anchor::                    Defining arbitrary cross-reference targets
* @link::                      How to make a plain link.
* @inforef::                   How to refer to an Info-only file.
* @url::                       How to refer to a uniform resource locator.
* @cite::                      How to refer to books not in the Info system.
* PDF Colors::                 Colorizing URLs and other links in PDF output.

‘@url’, ‘@uref{URL[, TEXT][, REPLACEMENT]}’

* @url Examples::              Examples of using all the forms of ‘@url’.
* URL Line Breaking::          How lines are broken within ‘@url’ text.
* @url PDF Output Format::     A special option to hide links in PDF output.

Marking Text, Words and Phrases

* Indicating::                 How to indicate definitions, files, etc.
* Emphasis::                   How to emphasize text.

Indicating Definitions, Commands, etc.

* Useful Highlighting::        Highlighting provides useful information.
* @code::                      Indicating program code.
* @kbd::                       Showing keyboard input.
* @key::                       Specifying keys.
* @samp::                      Indicating a literal sequence of characters.
* @verb::                      Indicating a verbatim sequence of characters.
* @var::                       Indicating metasyntactic variables.
* @env::                       Indicating environment variables.
* @file::                      Indicating file names.
* @command::                   Indicating command names.
* @option::                    Indicating option names.
* @dfn::                       Specifying definitions.
* @abbr::                      Indicating abbreviations.
* @acronym::                   Indicating acronyms.
* @indicateurl::               Indicating an example URL.
* @email::                     Indicating an electronic mail address.

Emphasizing Text

* @emph @strong::              How to emphasize text in Texinfo.
* Smallcaps::                  How to use the small caps font.
* Fonts::                      Various font commands for printed output.

Quotations and Examples

* Block Enclosing Commands::   Different constructs for different purposes.
* @quotation::                 Writing a quotation.
* @indentedblock::             Block of text indented on left.
* @example::                   Writing an example in a fixed-width font.
* @verbatim::                  Writing a verbatim example.
* @lisp::                      Illustrating Lisp code.
* @display::                   Writing an example in the current font.
* @format::                    Writing an example without narrowed margins.
* @exdent::                    Undo indentation on a line.
* @flushleft @flushright::     Pushing text flush left or flush right.
* @raggedright::               Avoiding justification on the right.
* @noindent::                  Preventing paragraph indentation.
* @indent::                    Forcing paragraph indentation.
* @cartouche::                 Drawing rounded rectangles around text.
* small::                      Examples in a smaller font.

Lists and Tables

* Introducing Lists::          Texinfo formats lists for you.
* @itemize::                   How to construct a simple list.
* @enumerate::                 How to construct a numbered list.
* Two-column Tables::          How to construct a two-column table.
* Multi-column Tables::        How to construct generalized tables.

Making a Two-column Table

* @table::                     How to construct a two-column table.
* @ftable @vtable::            Automatic indexing for two-column tables.
* @itemx::                     How to put more entries in the first column.

‘@multitable’: Multi-column Tables

* Multitable Column Widths::   Defining multitable column widths.
* Multitable Rows::            Defining multitable rows, with examples.

Special Displays

* Floats::                     Figures, tables, and the like.
* Images::                     Including graphics and images.
* Footnotes::                  Writing footnotes.

Floats

* @float::                     Producing floating material.
* @caption @shortcaption::     Specifying descriptions for floats.
* @listoffloats::              A table of contents for floats.

Inserting Images

* Image Syntax::
* Image Scaling::

Footnotes

* Footnote Commands::          How to write a footnote in Texinfo.
* Footnote Styles::            Controlling how footnotes appear.

Indices

* Predefined Indices::         Use different indices for different kinds of
                               entries.
* Indexing Commands::          How to make an index entry.
* Advanced Indexing::          Advanced indexing commands.
* Index Entries::              Choose different words for index entries.
* Printing Indices & Menus::   How to print an index in hardcopy and generate
                               index menus in Info.
* Combining Indices::          How to combine indices.
* New Indices::                How to define your own indices.

Combining Indices

* @syncodeindex::              How to merge two indices, using ‘@code’ font for
                               the merged-from index.
* @synindex::                  How to merge two indices, using the roman font
                               for the merged-from index.

Special Insertions

* Special Characters::         Inserting @ {} , \ # &
* Inserting Quote Characters:: Inserting left and right quotes, in code.
* Inserting Space::            Inserting the right amount of whitespace.
* Inserting Accents::          Inserting accents and special characters.
* Inserting Quotation Marks::  Inserting quotation marks.
* Inserting Subscripts and Superscripts::  Inserting sub/superscripts.
* Inserting Math::             Formatting mathematical expressions.
* Glyphs for Text::            Inserting dots, bullets, currencies, etc.
* Glyphs for Programming::     Indicating results of evaluation, expansion of
                               macros, errors, etc.
* Inserting Unicode::          Inserting a Unicode character by code point.

Special Characters: Inserting @ {} , \ # &

* Inserting an Atsign::        ‘@@’, ‘@atchar{}’.
* Inserting Braces::           ‘@{ @}’, ‘@l rbracechar{}’.
* Inserting a Comma::          , and ‘@comma{}’.
* Inserting a Backslash::      \ and ‘@backslashchar{}’.
* Inserting a Hashsign::       # and ‘@hashchar{}’.
* Inserting an Ampersand::     & and ‘@ampchar{}’.

Inserting Space

* Multiple Spaces::            Inserting multiple spaces.
* Not Ending a Sentence::      Sometimes a . doesn't end a sentence.
* Ending a Sentence::          Sometimes it does.
* @frenchspacing::             Specifying end-of-sentence spacing.
* @dmn::                       Formatting a dimension.

Glyphs for Text

* @TeX @LaTeX::                The TeX logos.
* @copyright::                 The copyright symbol (c in a circle).
* @registeredsymbol::          The registered symbol (R in a circle).
* @dots::                      How to insert ellipses: ... and ...
* @bullet::                    How to insert a bullet: •
* @euro::                      How to insert the euro currency symbol.
* @pounds::                    How to insert the pounds currency symbol.
* @textdegree::                How to insert the degrees symbol.
* @minus::                     How to insert a minus sign.
* @geq @leq::                  How to insert greater/less-than-or-equal signs.

Glyphs for Programming

* Glyphs Summary::             List of the glyph commands.
* @result::                    How to show the result of expression.
* @expansion::                 How to indicate an expansion.
* @print::                     How to indicate generated output.
* @error::                     How to indicate an error message.
* @equiv::                     How to indicate equivalence.
* @point::                     How to indicate the location of point.
* Click Sequences::            Inserting GUI usage sequences.

Forcing and Preventing Breaks

* Break Commands::             Summary of break-related commands.
* Line Breaks::                Forcing line breaks.
* @- @hyphenation::            Helping TeX with hyphenation points.
* @allowcodebreaks::           Controlling line breaks within @code text.
* @w::                         Preventing unwanted line breaks in text.
* @tie::                       Inserting an unbreakable but varying space.
* @sp::                        Inserting blank lines.
* @page::                      Forcing the start of a new page.
* @group::                     Preventing unwanted page breaks.
* @need::                      Another way to prevent unwanted page breaks.

Definition Commands

* Def Cmd Template::           Writing descriptions using definition commands.
* Def Cmd Continuation Lines:: Continuing the heading over source lines.
* Optional Arguments::         Handling optional and repeated arguments.
* No Space After Definition Name::  How to omit space after name.
* @deffnx::                    Group two or more 'first' lines.
* Def Cmds in Detail::         Reference for all the definition commands.
* Generic Definition Commands::  Without automatic index entries.
* Def Cmd Conventions::        Conventions for writing definitions.
* Sample Function Definition:: An example.

The Definition Commands

* Functions Commands::         Commands for functions and similar entities.
* Typed Functions::            Commands for functions in typed languages.
* Variables Commands::         Commands for variables and similar entities.
* Typed Variables::            Commands for variables in typed languages.
* Data Types::                 The definition command for data types.
* Abstract Objects::           Commands for object-oriented programming.

Object-Oriented Programming

* Variables: Object-Oriented Variables.
* Methods:   Object-Oriented Methods.

Internationalization

* @documentlanguage::          Declaring the current language.
* @documentencoding::          Declaring the input encoding.

Conditionally Visible Text

* Conditional Commands::       Text for a given format.
* Conditional Not Commands::   Text for any format other than a given one.
* Raw Formatter Commands::     Using raw formatter commands.
* Inline Conditionals::        Brace-delimited conditional text.
* @set @clear @value::         Variable tests and substitutions.
* Testing for Texinfo Commands::  Testing if a Texinfo command is available.
* Conditional Nesting::        Using conditionals inside conditionals.

Flags: ‘@set’, ‘@clear’, conditionals, and ‘@value’

* @set @value::                Expand a flag variable to a string.
* @ifset @ifclear::            Format a region if a flag is set.
* @inlineifset @inlineifclear::  Brace-delimited flag conditionals.
* @value Example::             An easy way to update edition information.

Defining New Texinfo Commands

* Defining Macros::            Defining and undefining new commands.
* Invoking Macros::            Using a macro, once you've defined it.
* Macro Details::              Limitations of Texinfo macros.
* @alias::                     Command aliases.
* Line Macros::                Macros using whole line for arguments.
* @definfoenclose::            Customized highlighting.
* External Macro Processors::  ‘#line’ directives.

External Macro Processors: Line Directives

* #line Directive::
* #line and TeX::
* #line Syntax Details::

Include Files

* Using Include Files::        How to use the ‘@include’ command.
* Sample Include File::        A sample outer file with included files within
                               it; and a sample included file.
* @verbatiminclude::           Including a file verbatim.

Formatting and Printing with TeX

* Use TeX::                    Use TeX to format for hardcopy.
* Format with texi2dvi or texi2pdf::  The simplest way to format.
* Format with tex/texindex::   Formatting with explicit shell commands.
* Preparing for TeX::          What to do before you use TeX.
* Overfull hboxes::            What are and what to do with overfull hboxes.
* Printing Japanese and Chinese::  XeTeX or LuaTeX required.

Format with ‘tex’/‘texindex’

* Formatting Partial Documents::
* Details of texindex::

‘texi2any’: The Translator for Texinfo

* Invoking texi2any::          Running the translator from a shell.
* texi2any Environment Variables::  Control over output format and XS use.
* texi2any Printed Output::    Calling ‘texi2dvi’.
* Customization Variables::    Configuring ‘texi2any’.
* Internationalization of Document Strings::  Translating program-inserted
                               text.
* Invoking pod2texi::          Translating Perl Pod to Texinfo.
* texi2html::                  An ancestor of ‘texi2any’.

Customization Variables

* Commands: Customization Variables for @-Commands.
* Options:  Customization Variables and Options.
* Global:   Global Customization Variables.
* Info:     Info and Plaintext Customization Variables.
* LaTeX:    LaTeX Customization Variables.
* Other:    Other Formats Customization Variables.
* Formats:  Customization Variables for Multiple Formats.

Invoking ‘pod2texi’: Convert Pod to Texinfo

* pod2texi manual page::       ‘pod2texi’ invocation in a manual page format.

Creating and Installing Info Files

* Installing an Info File::
* Tag and Split Files::
* Info Format FAQ::

Installing an Info File

* Directory File::             The top-level menu for all Info files.
* New Info File::              Listing a new Info file.
* Other Info Directories::     How to specify Info files that are located in
                               other directories.
* Installing Dir Entries::     How to specify what menu entry to add to the
                               Info directory.
* Invoking install-info::      ‘install-info’ options.

Generating HTML

* HTML Translation::           Details of the HTML output.
* HTML Splitting::             How HTML output is split.
* HTML CSS::                   Influencing HTML output with Cascading Style
                               Sheets.
* @documentdescription::       Document summary for the HTML output.
* Generating EPUB::            Details on the EPUB output.
* Syntax Highlighting::        Use syntax highlighting in code excerpts.
* HTML Xref::                  Standard algorithm for interoperability.
* HTML Output Customization::  Using customization variables.

Generating EPUB

* EPUB Output File and Directory::
* EPUB Cross-References::      No cross-references in EPUB output.
* EPUB Conformance::
* EPUB HTML::                  Variables set internally.

HTML Cross-references

* Link Basics:       HTML Xref Link Basics.
* Node Expansion:    HTML Xref Node Name Expansion.
* Command Expansion: HTML Xref Command Expansion.
* 8-bit Expansion:   HTML Xref 8-bit Character Expansion.
* Configuration:     HTML Xref Configuration.  ‘htmlxref.cnf’.

HTML Output Customization

* HTML Output Structure Customization::
* File Names and Links Customization for HTML::
* Customization of Navigation and Headers::
* HTML Features Customization::
* Customization of Inserted HTML Code::
* HTML Customization of Specific Output::
* HTML Customization for Math::
* JavaScript Interface and Licenses::
* HTML Customization Variables List::

HTML Customization for Math

* MathJax Customization Variables::
* latex2html Customization Variables::
* tex4ht Customization Variables::

@-Command Details

* Command Syntax::
* Command List::
* Command Contexts::
* Obsolete @-Commands::

Sample Texinfo Files

* GNU Sample Texts::
* Verbatim Copying License::
* All-permissive Copying License::

Using Texinfo Mode

* Texinfo Mode Overview::      How Texinfo mode can help you.
* Emacs Editing::              Texinfo mode adds to GNU Emacs' general purpose
                               editing features.
* Inserting::                  How to insert frequently used @-commands.
* Showing the Structure::      How to show the structure of a file.
* Updating Nodes and Menus::   How to update or create new nodes and menus.
* Info Formatting::            How to format for Info.
* Printing with Emacs::        How to format with TeX and print with Emacs.
* Texinfo Mode Summary::       Summary of all the Texinfo mode commands.
* Formatting Info files::      Processing directly Info files.
* Catching Mistakes::          How to find mistakes in formatting.
* Batch Formatting::           How to format for Info in Emacs batch mode.

Showing the Sectioning Structure of a File

* Using texinfo-show-structure::  How to use ‘texinfo-show-structure’.
* Using occur::                How to list all lines containing a pattern.

Updating Nodes and Menus

* Updating Commands::          Five major updating commands.
* Updating Requirements::      How to structure a Texinfo file for using the
                               updating command.
* Update Multiple Files::      How to create and update nodes and menus when
                               using included files.
* Include Files Requirements:: How to structure outer file and include files
                               for the updating command.
* Other Updating Commands::    How to indent descriptions, insert missing nodes
                               lines, and update nodes in sequence.

Formatting for Info

* texi2any in Emacs::          How to run ‘texi2any’ from Emacs.
* texinfo-format commands::    Two Info formatting commands written in Emacs
                               Lisp are an alternative to ‘texi2any’.

Formatting and Printing with Emacs

* Texinfo Mode Printing::      How to format and print part or all of a file.
* Compile-Command::            How to print using Emacs's compile command.

Direct Formatting of Info files

* Tagifying::                  How to tagify a file.
* Splitting::                  How to split a file manually.

Catching Mistakes

* texi2any Preferred::         ‘texi2any’ finds errors.
* Debugging with Info::        How to catch errors with Info formatting.
* Debugging with TeX::         How to catch errors with TeX formatting.
* Running Info-validate::      How to find badly referenced nodes.

Finding Badly Referenced Nodes

* Using Info-validate::        How to run ‘Info-validate’.
* Unsplit and Tagify::         How to create an unsplit file and add a tag
                               table for validation.

Global Document Commands

* @setchapternewpage::         Start chapters on right-hand pages.
* Headings::                   Page headings.
* @paragraphindent::           Specify paragraph indentation.
* @firstparagraphindent::      Suppressing first paragraph indentation.
* @exampleindent::             Specify environment indentation.
* @smallbook::                 How to print small format books and manuals.
* A4 Paper::                   How to print on A4, A5 or B6 paper.
* @pagesizes::                 How to print with customized page sizes.
* Microtypography::            Improving the appearance of paragraphs.
* Magnification::              How to print scaled up output.

Page Headings

* @headings::                  An option for turning headings on and off and
                               double or single sided printing.
* Heading Format::             Standard page heading formats.
* Custom Headings::            How to create your own headings and footings.

Info Format Specification

* Whole:           Info Format Whole Manual.  Split vs. nonsplit manuals.
* Preamble:        Info Format Preamble.
* Indirect:        Info Format Indirect Table.
* Tag table:       Info Format Tag Table.
* Local variables: Info Format Local Variables.
* Regular nodes:   Info Format Regular Nodes.
* Menu:            Info Format Menu.
* Image:           Info Format Image.
* Printindex:      Info Format Printindex.
* Cross-Reference: Info Format Cross Reference.


File: texinfo.info,  Node: Copying Conditions,  Next: Overview,  Prev: Top,  Up: Top

Texinfo Copying Conditions
**************************

GNU Texinfo is “free software”; this means that everyone is free to use
it and free to redistribute it on certain conditions.  Texinfo is not in
the public domain; it is copyrighted and there are restrictions on its
distribution, but these restrictions are designed to permit everything
that a good cooperating citizen would want to do.  What is not allowed
is to try to prevent others from further sharing any version of Texinfo
that they might get from you.

   Specifically, we want to make sure that you have the right to give
away copies of the programs that relate to Texinfo, that you receive
source code or else can get it if you want it, that you can change these
programs or use pieces of them in new free programs, and that you know
you can do these things.

   To make sure that everyone has such rights, we have to forbid you to
deprive anyone else of these rights.  For example, if you distribute
copies of the Texinfo related programs, you must give the recipients all
the rights that you have.  You must make sure that they, too, receive or
can get the source code.  And you must tell them their rights.

   Also, for our own protection, we must make certain that everyone
finds out that there is no warranty for the programs that relate to
Texinfo.  If these programs are modified by someone else and passed on,
we want their recipients to know that what they have is not what we
distributed, so that any problems introduced by others will not reflect
on our reputation.

   The precise conditions of the licenses for the programs currently
being distributed that relate to Texinfo are found in the General Public
Licenses that accompany them.  This manual is covered by the GNU Free
Documentation License (*note GNU Free Documentation License::).


File: texinfo.info,  Node: Overview,  Next: Writing a Texinfo File,  Prev: Copying Conditions,  Up: Top

1 Overview of Texinfo
*********************

“Texinfo” is a documentation system that uses a single source file to
produce both online information and printed output.  This means that
instead of writing several different documents, one for each output
format, you need only write one document.

   Using Texinfo, you can create a printed document (via the TeX
typesetting system) in PDF format, including chapters, sections,
cross-references, and indices.  From the same Texinfo source file, you
can create HTML output suitable for use with a web browser, you can
create an Info file for use in GNU Emacs or other Info-reading programs,
and also create DocBook, EPUB 3, or LaTeX files.

   A Texinfo source file is a plain text file containing text
interspersed with “@-commands” (words preceded by an ‘@’) that tell the
Texinfo processors what to do.  Texinfo's markup commands are almost
entirely “semantic”; that is, they specify the intended meaning of text
in the document, rather than physical formatting instructions.

   GNU Emacs has a special mode, called Texinfo mode, that provides
various Texinfo-related features.  (*Note Texinfo Mode::.)

   Texinfo was devised specifically for the purpose of writing software
documentation and manuals.  If you want to write a good manual for your
program, Texinfo has many features which we hope will make your job
easier.  However, Texinfo is not intended to be a general-purpose
formatting program.  It provides almost no commands for controlling the
final formatting, so may be inappropriate for your needs if you want to
lay out a newspaper, devise a glossy magazine ad, or follow the exact
formatting requirements of a publishing house.

   Spell "Texinfo" with a capital "T" and the other letters in
lowercase.  The first syllable of "Texinfo" is pronounced like "speck",
not "hex".  This odd pronunciation is derived from the pronunciation of
TeX.  Pronounce TeX as if the ‘X’ were the last sound in the name
'Bach'.  In the word TeX, the ‘X’ is, rather than the English letter
"ex", actually the Greek letter "chi".

   Texinfo is the official documentation format of the GNU project.
More information, including manuals for GNU packages, is available at
the GNU documentation web page (http://www.gnu.org/doc/).

* Menu:

* Reporting Bugs::             Submitting effective bug reports.
* Output Formats::             Overview of the supported output formats.
* Info Files::                 What is an Info file?
* Printed Books::              Characteristics of a printed book or manual.
* Adding Output Formats::      Man pages and implementing new formats.
* History::                    Acknowledgements, contributors and genesis.


File: texinfo.info,  Node: Reporting Bugs,  Next: Output Formats,  Up: Overview

1.1 Reporting Bugs
==================

We welcome bug reports and suggestions for any aspect of the Texinfo
system: programs, documentation, installation, etc.  Please email them
to <bug-texinfo@gnu.org>.  You can get the latest version of Texinfo via
its home page, <https://www.gnu.org/software/texinfo>.

   For bug reports, please include enough information for the
maintainers to reproduce the problem.  Generally speaking, that means:

   • The version number of Texinfo and the program(s) or manual(s)
     involved.
   • The contents of any input files necessary to reproduce the bug.
   • Precisely how you ran any program(s) involved.
   • A description of the problem and samples of any erroneous output.
   • Hardware and operating system names and versions.
   • Anything else that you think would be helpful.

   When in doubt whether something is needed or not, include it.  It's
better to include too much than to leave out something important.

   It is critical to send an actual input file that reproduces the
problem.

   Any problems with the Info reader in Emacs should be reported to the
Emacs developers: see *note (emacs)Bugs::.

   Patches are welcome; if possible, please make them with ‘diff -c’,
‘diff -u’ (*note (diffutils)Top::), or ‘git diff’ and include
‘ChangeLog’ entries (*note (standards)Change Logs::), and follow the
existing coding style.


File: texinfo.info,  Node: Output Formats,  Next: Info Files,  Prev: Reporting Bugs,  Up: Overview

1.2 Output Formats
==================

Here is an overview of the output formats currently supported by
Texinfo.

Info
     (Generated via ‘texi2any’.)  Info format is mostly a plain text
     transliteration of the Texinfo source.  It adds a few control
     characters to provide navigational information for
     cross-references, indices, and so on.  The Emacs Info subsystem
     (*note (info)Top::), and the standalone ‘info’ program (*note
     (info-stnd)Top::), among others, can read these files.  *Note Info
     Files::, and *note Creating and Installing Info Files::.

Plain text
     (Generated via ‘texi2any --plaintext’.)  This is almost the same as
     Info output with the navigational control characters omitted.

HTML
     (Generated via ‘texi2any --html’.)  HTML, standing for Hyper Text
     Markup Language, is the language for writing documents on the World
     Wide Web.  Web browsers can render this language online.  There are
     many versions of HTML, both different standards and
     browser-specific variations.  ‘texi2any’ uses a subset of the
     language that can be interpreted by any common browser,
     intentionally not using many newer or less widely-supported tags.
     Although the native output is thus rather plain, it can be
     customized at various levels, if desired.  *Note Generating HTML::.

EPUB 3
     (Generated via ‘texi2any --epub3’.)  EPUB is a format designed for
     reading electronic books on portable devices.  It is a derivative
     of HTML.  The format was developed by the International Digital
     Publishing Forum (IDPF), which is now part of the World Wide Web
     Consortium (W3C).  The latest major revision, EPUB 3, dates from
     2011.

DVI
     (Generated via ‘texi2dvi’.)  The DeVIce Independent binary format
     is output by the TeX typesetting program (<http://tug.org>).  This
     is then read by a DVI 'driver', which knows the actual
     device-specific commands that can be viewed or printed, notably
     Dvips for translation to PostScript (*note (dvips)Top::) and Xdvi
     for viewing on an X display
     (<http://sourceforge.net/projects/xdvi/>).  *Note Hardcopy with
     TeX::.  (Be aware that the Texinfo language is very different from
     TeX's usual languages: plain TeX, LaTeX, ConTeXt, etc.)

PostScript
     (Generated via ‘texi2dvi --ps’.)  PostScript is a page description
     language that became widely used around 1985 and is still used
     today.  <https://en.wikipedia.org/wiki/PostScript> gives a basic
     description and more preferences.  By default, Texinfo uses the
     ‘dvips’ program to convert TeX's DVI output to PostScript.  *Note
     (dvips)Top::.

PDF
     (Generated via ‘texi2dvi --pdf’ or ‘texi2pdf’.)  This format was
     developed by Adobe Systems for portable document interchange, based
     on their previous PostScript language.  It can represent the exact
     appearance of a document, including fonts and graphics, and
     supporting arbitrary scaling.  It is intended to be
     platform-independent and easily viewable, among other design goals;
     <https://en.wikipedia.org/wiki/Portable_Document_Format> and
     <http://tug.org/TUGboat/tb22-3/tb72beebe-pdf.pdf> have some
     background.  By default, Texinfo uses the ‘pdftex’ program, an
     extension of TeX, to output PDF; see
     <http://tug.org/applications/pdftex>.  *Note PDF Output::.

LaTeX
     (Generated via ‘texi2any --latex’.)  This is a typesetting system
     built on top of TeX.  It was originally released by Leslie Lamport
     in 1984.  LaTeX adds more definitions to those of TeX and has a
     wide range of packages built on it.  LaTeX is ubiquitous in
     academic literature.  The current version of LaTeX is under active
     development; more information is available online at
     <https://www.latex-project.org/>.

     The LaTeX output can be further processed into DVI, PostScript, or
     PDF.  In theory, the LaTeX output should allow for much more
     customizability of the output than would be possible with the plain
     TeX implementation of Texinfo.

DocBook
     (Generated via ‘texi2any --docbook’.)  This is an XML-based format,
     primarily for technical documentation.  It therefore bears some
     resemblance, in broad outline, to Texinfo.  See
     <http://www.docbook.org>.  Various converters from DocBook _to_
     Texinfo have also been developed; see the Texinfo web pages.

XML
     (Generated via ‘texi2any --xml’.)  The ‘texi2any’ XML output,
     unlike all the other output formats, is a transliteration of the
     Texinfo source, rather than finished output.  Texinfo XML files
     cannot be viewed in web browsers or other programs.

     XML is a generic syntax specification usable for any sort of
     content.  (A reference is at <http://www.w3.org/XML>.)  The purpose
     of the Texinfo XML output is to allow further processing by XML
     tools.  The output syntax is defined in an XML DTD, which is
     contained in a file ‘texinfo.dtd’ included in the Texinfo source
     distribution.

     The Texinfo source distribution includes a utility script
     ‘txixml2texi’ to do a backward transformation to recreate the
     original Texinfo content (except for Texinfo macros and
     conditionals).


File: texinfo.info,  Node: Info Files,  Next: Printed Books,  Prev: Output Formats,  Up: Overview

1.3 Info Files
==============

As mentioned above, Info format is mostly a plain text transliteration
of the Texinfo source, with the addition of a few control characters to
separate nodes and provide navigational information, so that
Info-reading programs can operate on it.

   Info files are nearly always created by processing a Texinfo source
document.  ‘texi2any’, also known as ‘makeinfo’, is the principal
command that converts a Texinfo file into an Info file; *note Generic
Translator texi2any::.

   Generally, you enter an Info file through a node that by convention
is named 'Top'.  This node normally contains just a brief summary of the
file's purpose, and a large menu through which the rest of the file is
reached.  From this node, you can either traverse the file
systematically by going from node to node, or you can go to a specific
node listed in the main menu, or you can search the index menus and then
go directly to the node that has the information you want.
Alternatively, with the standalone Info program, you can specify
specific menu items on the command line (*note (info)Top::).

   If you want to read through an Info file in sequence, as if it were a
printed manual, you can hit <SPC> repeatedly, or you get the whole file
with the advanced Info command ‘g *’.  (*Note Advanced Info commands:
(info)Advanced.)

   The ‘dir’ file in the ‘info’ directory serves as the departure point
for the whole Info system.  From it, you can reach the 'Top' nodes of
each of the documents in a complete Info system.

   If you wish to refer to an Info file via a URI, you can use the
(unofficial) syntax exemplified by the following.  This works with
Emacs/W3, for example:
     info:emacs#Dissociated%20Press
     info:///usr/info/emacs#Dissociated%20Press
     info://localhost/usr/info/emacs#Dissociated%20Press

   The ‘info’ program itself does not follow URIs of any kind.


File: texinfo.info,  Node: Printed Books,  Next: Adding Output Formats,  Prev: Info Files,  Up: Overview

1.4 Printed Books
=================

A Texinfo file can be formatted and typeset as a printed book or manual.
To do this, you need TeX, a sophisticated typesetting program written by
Donald Knuth of Stanford University.  It is not part of the Texinfo
distribution.

   Texinfo provides a file ‘texinfo.tex’ that contains the definitions
that TeX uses when it typesets a Texinfo file.  You can get the latest
version of ‘texinfo.tex’ from the Texinfo home page,
<https://www.gnu.org/software/texinfo/>.

   A Texinfo-based book is similar to any other typeset, printed work:
it can have a title page, copyright page, table of contents, and
preface, as well as chapters, numbered or unnumbered sections and
subsections, page headers, cross-references, footnotes, and indices.

   TeX is very powerful and has a great many features.  However, because
a Texinfo file must be able to present information both on a
character-only terminal in Info form and in a typeset book, the
formatting commands that Texinfo supports are necessarily limited.

   *Note Hardcopy with TeX::, for more information on processing a
manual with TeX.


File: texinfo.info,  Node: Adding Output Formats,  Next: History,  Prev: Printed Books,  Up: Overview

1.5 Adding Output Formats
=========================

The output formats in the previous sections handle a wide variety of
usage, but of course there is always room for more.

   If you are a programmer and would like to contribute to the GNU
project by implementing additional output formats for Texinfo, that
would be excellent.  The way to do this that would be most useful is to
write a new back-end for ‘texi2any’, our reference implementation of a
Texinfo parser; it creates a tree representation of the Texinfo input
that you can use for the conversion.  The documentation in the source
file ‘tp/Texinfo/Convert/Converter.pm’ is a good place to start (*note
(texi2any_internals)Texinfo::Convert::Converter::).  *Note Generic
Translator texi2any::.

   Another viable approach is use the Texinfo XML output from ‘texi2any’
as your input.  This XML is an essentially complete representation of
the input, but without the Texinfo syntax and option peculiarities, as
described above.

   If you still cannot resist the temptation of writing a new program
that reads Texinfo source directly, let us give some more caveats:
please do not underestimate the amount of work required.  Texinfo is by
no means a simple language to parse correctly, and remains under
development, so you would be committing to an ongoing task.  You are
advised to check that the tests of the language that come with
‘texi2any’ give correct results with your new program.

   From time to time, proposals are made to generate traditional Unix
man pages from Texinfo source.  However, because man pages have a strict
conventional format, creating a good man page requires a completely
different source from that needed for the typical Texinfo applications
of writing a good user tutorial and/or a good reference manual.  This
makes generating man pages incompatible with the Texinfo design goal of
not having to document the same information in different ways for
different output formats.  You might as well write the man page
directly.

   As an alternative way to support man pages, you may find the program
‘help2man’ to be useful.  It generates a traditional man page from the
‘--help’ output of a program.  In fact, the man pages for the programs
in the Texinfo distribution are generated with this.  It is GNU software
written by Brendan O'Dea, available from
<http://www.gnu.org/software/help2man>.


File: texinfo.info,  Node: History,  Prev: Adding Output Formats,  Up: Overview

1.6 History
===========

Richard M. Stallman invented the Texinfo format, wrote the initial
processors, and created Edition 1.0 of this manual.  Robert J. Chassell
greatly revised and extended the manual, starting with Edition 1.1.
Brian Fox was responsible for the standalone Texinfo distribution until
version 3.8.  Karl Berry continued maintenance from Texinfo 3.8 (manual
edition 2.22), and Gavin Smith has continued maintenance since Texinfo
6.0.

Beginnings
----------

Richard Stallman included an on-line, hypertext help system called Info
in the original implementation of Emacs (in 1975/6).  Stallman had been
inspired after seeing a presentation a couple of years earlier on the
"NLS" hypertext system of Douglas Engelbart.

   In another development, in the 1970's at CMU, Brian Reid developed a
program and format named Scribe to mark up documents for printing.  It
used the ‘@’ character to introduce commands, as Texinfo does.  Much
more consequentially, it strove to describe document contents rather
than formatting, an idea wholeheartedly adopted by Texinfo.

   Meanwhile, people at MIT developed another format called Bolio.
Richard Stallman (RMS) worked on converting Bolio to use TeX as its
typesetting language, resulting in BoTeX.  The earliest BoTeX version
seems to have been 0.02 on October 31, 1984.

   BoTeX could only be used as a markup language for documents to be
printed, not for online documents.  RMS combined BoTeX and Info to
create Texinfo, a mark-up language for text that is intended to be read
both online and as printed hard copy.

   The original translator to create Info was written (primarily by RMS
and Bob Chassell) in Emacs Lisp, namely the ‘texinfo-format-buffer’ and
other functions.  In the early 1990s, Brian Fox reimplemented the
conversion program in C, now called ‘makeinfo’, as well as the
standalone ‘info’ program.

Reimplementing in Perl
----------------------

In 2012, the C ‘makeinfo’ was itself replaced by a Perl implementation
generically called ‘texi2any’.  This version supports the same level of
output customization as ‘texi2html’, an independent program originally
written by Lionel Cons, later with substantial work by many others.  The
many additional features needed to make ‘texi2html’ a replacement for
‘makeinfo’ were implemented by Patrice Dumas.  The first, never-released
version of ‘texi2any’ was based on the ‘texi2html’ code.

   That implementation, however, was abandoned in favor of the current
program (also written by Patrice Dumas), which parses the Texinfo input
into a tree for processing.  It inherited the design of customization
and other features from ‘texi2html’ (for more on ‘texi2html’
compatibility, *note texi2html::).  However, ‘texi2any’ is a full
reimplementation: it constructs a tree-based representation of the input
document for all back-ends to work from.

   The new Perl program is much slower than the old C program.  The
speed gap has partially closed since first release, but it may not ever
be entirely comparable.  So why did we switch?  In short, we intend and
hope that the present program will be much easier than the previous C
implementation of ‘makeinfo’ to extend to different output styles,
back-end output formats, and all other customizations.  In more detail:

   • HTML customization.  Many GNU and other free software packages had
     been happily using the HTML customization features in ‘texi2html’
     for years.  Thus, in effect two independent implementations of the
     Texinfo language had developed, and keeping them in sync was not
     simple.  Adding the HTML customization possible in ‘texi2html’ to a
     C program would have been an enormous effort.

   • Unicode, and multilingual support generally, especially of east
     Asian languages.  At that time, doing it in C would have been
     tantamount to rewriting the entire program.  Since then, the parser
     and bits of converter back-ends have been rewritten in C, but the
     converter back-ends are still mostly in Perl which has good
     multilingual support built in.

   • Additional back-ends.  The ‘makeinfo’ code had become convoluted to
     the point where adding a new back-end was quite complex, requiring
     complex interactions with existing back-ends.  In contrast, the new
     implementation provides a clean tree-based representation for all
     back-ends to work from.  People have requested numerous different
     back-ends (LaTeX, the latest (X)HTML, ...); this change made them
     much more feasible to implement.  Which leads to the last item:

   • Making contributions easier.  In general, due to the cleaner
     structure, the separate parser/back-ends implementation should be
     considerably easier than the former C ‘makeinfo’ implementation for
     anyone to read and contribute to, with the resulting obvious
     benefits.  After ten years, contributed back-ends were yet to
     happen, but it is still believed that this structure could in
     theory lend better to contributions.

   ‘texi2any’ is intended to be a reference implementation that defines
parts of the language not fully specified by the manual.  Without such a
reference, alternative implementations would be very likely to have
subtle, or not-so-subtle, differences in behavior, and thus Texinfo
documents would become dependent on the processor.  It is also important
to have consistent command-line options for all processors.  Extensive
tests of the language and processor were developed at the same time as
‘texi2any’; we encourage anyone thinking of writing a program to parse
Texinfo input to make use of these tests.

   With the release of ‘texi2any’ as the reference implementation,
development of both the C implementation of ‘makeinfo’ and ‘texi2html’
has been halted.  Going forward, we ask authors of Texinfo documents to
use only ‘texi2any’.


File: texinfo.info,  Node: Writing a Texinfo File,  Next: Nodes,  Prev: Overview,  Up: Top

2 Writing a Texinfo File
************************

This chapter describes Texinfo syntax and what is required in a Texinfo
file, and gives a short sample file.

* Menu:

* Conventions::                General rules for writing a Texinfo file.
* Comments::                   Writing comments and ignored text in general.
* Minimum::                    What a Texinfo file must have.
* Short Sample Texinfo File::  A short sample Texinfo file.
* Texinfo File Header::        The first lines.
* Directory Category::         A category for a manual.
* Document Permissions::       Ensuring your manual is free.
* Titlepage & Copyright Page:: Creating the title and copyright pages.
* Contents::                   How to create a table of contents.
* The Top Node::               Creating the 'Top' node and master menu.
* The Body of the Document::   The rest of the nodes.
* Ending a File::              What is at the end of a Texinfo file?


File: texinfo.info,  Node: Conventions,  Next: Comments,  Up: Writing a Texinfo File

2.1 General Syntactic Conventions
=================================

This section describes the general conventions used in all Texinfo
documents.

   • All printable ASCII characters except ‘@’, ‘{’ and ‘}’ can appear
     in a Texinfo file and stand for themselves.  ‘@’ is the escape
     character which introduces commands, while ‘{’ and ‘}’ are used to
     surround arguments to certain commands.  To put one of these
     special characters into the document, put an ‘@’ character in front
     of it, like this: ‘@@’, ‘@{’, and ‘@}’.

   • In a Texinfo file, the commands you write to describe the contents
     of the manual are preceded by an ‘@’ character; they are called
     “@-commands”.  (The ‘@’ in Texinfo has the same meaning that ‘\’
     has in plain TeX.)

     Depending on what they do or what arguments they take, you need to
     write @-commands on lines of their own, or as part of sentences.
     As a general rule, a command requires braces if it mingles among
     other text; but it does not need braces if it is on a line of its
     own.  For more details of Texinfo command syntax, see *note Command
     Syntax::.

   • Whitespace following an @-command name is optional and (usually)
     ignored if present.  The exceptions are contexts when whitespace is
     significant, e.g., an ‘@example’ environment.

   • Texinfo supports the usual quotation marks used in English and in
     other languages; see *note Inserting Quotation Marks::.

   • Use three hyphens in a row, ‘---’, to produce a long dash--like
     this (called an “em dash”), used for punctuation in sentences.  Use
     two hyphens, ‘--’, to produce a medium dash (called an “en dash”),
     used primarily for numeric ranges, as in "June 25-26".  Use a
     single hyphen, ‘-’, to produce a standard hyphen used in compound
     words.  For display on the screen, Info reduces three hyphens to
     two and two hyphens to one (not transitively!).  Of course, any
     number of hyphens in the source remain as they are in literal
     contexts, such as ‘@code’ and ‘@example’.

   • _Whitespace_.  Texinfo files are plain text files composed of lines
     terminated by the usual newline character (line feed).  Texinfo
     processors read input one line at a time.  Paragraphs are
     terminated by an empty line or a line containing only spaces.  A
     sequence of several spaces in text is usually treated the same as a
     single space (except in verbatim modes).

     Form feed (‘CTRL-l’) characters terminate any open paragraph.
     Other form feeds, as well other ASCII whitespace (tab, carriage
     return) are treated the same as space characters (although the
     results may differ depending on the output format).  Hence, there
     is not much point in using these whitespace characters in
     documents.  Non-ASCII spaces, such as Unicode "em space", are not
     recognized as whitespace at all, and will be treated as regular,
     non-whitespace characters.

     However, in verbatim modes, for example in code samples, tab
     characters may produce the correct formatting in the output.


File: texinfo.info,  Node: Comments,  Next: Minimum,  Prev: Conventions,  Up: Writing a Texinfo File

2.2 Comments
============

You can write comments in a Texinfo file by using the ‘@comment’
command, which may be abbreviated to ‘@c’.  Such comments are for a
person looking at the Texinfo source file.  All the text on a line that
follows either ‘@comment’ or ‘@c’ is a comment; the rest of the line
does not appear in the visible output.  (To be precise, the character
after the ‘@c’ or ‘@comment’ must be something other than a dash or
alphanumeric, or it will be taken as part of the command.)

   Often, you can write the ‘@comment’ or ‘@c’ in the middle of a line,
and only the text that follows after the ‘@comment’ or ‘@c’ command does
not appear; but some commands, such as ‘@settitle’, work on a whole
line.  You cannot use ‘@comment’ or ‘@c’ within a line beginning with
such a command.

   In cases of nested command invocations, complicated macro
definitions, etc., ‘@c’ and ‘@comment’ may provoke an error when
processing with TeX.  Therefore, you can also use the ‘DEL’ character
(ASCII 127 decimal, 0x7f hex, 0177 octal) as a true TeX comment
character (catcode 14, in TeX internals).  Everything on the line after
the ‘DEL’ will be ignored and the next line will be merged.

   You can also have long stretches of text ignored by the Texinfo
processors with the ‘@ignore’ and ‘@end ignore’ commands.  Write each of
these commands on a line of its own, starting each command at the
beginning of the line.  Text between these two commands does not appear
in the processed output.  You can use ‘@ignore’ and ‘@end ignore’ for
writing comments.  (For some caveats regarding nesting of such commands,
*note Conditional Nesting::.)


File: texinfo.info,  Node: Minimum,  Next: Short Sample Texinfo File,  Prev: Comments,  Up: Writing a Texinfo File

2.3 What a Texinfo File Must Have
=================================

By convention, the name of a Texinfo file ends with one of the
extensions ‘.texi’, ‘.texinfo’, ‘.txi’, or ‘.tex’.  Using ‘.tex’ is
discouraged as this extension is already used by TeX and LaTeX input
files.  The most common and recommended extension is ‘.texi’.  The name
of a Texinfo file should only contain ASCII characters.

   The output name is based on the input file name, in the default case.
First, any of the extensions ‘.texi’, ‘.tex’, ‘.txi’, or ‘.texinfo’ is
removed from the input file name; then, the output format specific
extension is added--‘.html’ when generating HTML, ‘.info’ when
generating Info, etc.  The output name should only contain ASCII
characters(1).

   In order to be made into a printed manual, a Texinfo file must begin
with a line like this:

     \input texinfo

The contents of the file follow this beginning, and then you must end
the Texinfo source with a line like this:

     @bye

   The ‘@bye’ line at the end of the file on a line of its own tells TeX
that the file is ended and to stop formatting.  If you leave this out,
you'll be dumped at TeX's prompt at the end of the run.

   Furthermore, you will usually provide a Texinfo file with a title, a
title page, indices, and the like, all of which are explained in this
manual.  But the minimum, which can be useful for short documents, is
just the one line at the beginning and the one line at the end.

   Without additional information, the input and output encodings are
assumed to be UTF-8, an universal codeset compatible with 7-bit ASCII.

   ---------- Footnotes ----------

   (1) ‘texi2any’ can handle non ASCII characters in input file names,
but non ASCII characters in output name will create problems for some
output formats, especially for cross-references.


File: texinfo.info,  Node: Short Sample Texinfo File,  Next: Texinfo File Header,  Prev: Minimum,  Up: Writing a Texinfo File

2.4 Short Sample
================

Here is a short sample Texinfo file.

     \input texinfo
     @settitle Sample Manual 1.0

     @copying
     This is a short example of a complete Texinfo file.

     Copyright @copyright{} 2016 Free Software Foundation, Inc.
     @end copying

     @titlepage
     @title Sample Title
     @page
     @vskip 0pt plus 1filll
     @insertcopying
     @end titlepage

     @contents

     @node Top
     @top GNU Sample

     This manual is for GNU Sample
     (version @value{VERSION}, @value{UPDATED}).

     @menu
     * First Chapter::    The first chapter is the
                           only chapter in this sample.
     * Index::            Complete index.
     @end menu


     @node First Chapter
     @chapter First Chapter

     @cindex chapter, first
     This is the first chapter.
     @cindex index entry, another

     Here is a numbered list.

     @enumerate
     @item
     This is the first item.

     @item
     This is the second item.
     @end enumerate


     @node First Section
     @section First Section

     First section of first chapter.


     @node Second Section
     @section Second Section

     Second section of first chapter.


     @node Index
     @unnumbered Index

     @printindex cp

     @bye


File: texinfo.info,  Node: Texinfo File Header,  Next: Directory Category,  Prev: Short Sample Texinfo File,  Up: Writing a Texinfo File

2.5 Texinfo File Header
=======================

Texinfo files start with the line:

     \input texinfo

   The ‘\input texinfo’ line tells TeX to use the ‘texinfo.tex’ file,
which tells TeX how to translate the Texinfo @-commands into TeX
typesetting commands.  (Note the use of the backslash, ‘\’; this is
correct for TeX.)

   It makes sense to include any command that affects document
formatting as a whole in the header.  The ‘@settitle’ line is usually
present at the beginning of the header:

     @settitle Sample Manual 1.0

   The ‘@settitle’ line specifies a title for the page headers (or
footers) of the printed manual, and the default title and document
description for the ‘<head>’ in HTML.  ‘@synindex’ (*note @synindex::),
for instance, is another command often included in the header.

   The start of the Texinfo file up to the first content that is output
as part of the main body of the document is the “preamble”.  It includes
the header, *note Document Permissions:: and *note Titlepage & Copyright
Page:: specification.  It is important for the LaTeX output format as
the end of preamble is where the ‘\begin{document}’ line is output.  In
other output formats it may be used to determine how some special output
is formatted, for example *note @copying:: output as a comment at the
beginning of output files, or the language used in file headers.

* Menu:

* First Line::                 The first line of a Texinfo file.
* @setfilename::               Give the name of the output file.
* @settitle::                  Create a title for the printed work.
* Preamble::                   Start of the Texinfo file up to first content.
* Start and End of Header::    Formatting a region in Emacs requires this.


File: texinfo.info,  Node: First Line,  Next: @setfilename,  Up: Texinfo File Header

2.5.1 The First Line of a Texinfo File
--------------------------------------

Every Texinfo file that is to be the top-level input to TeX must begin
with a line that looks like this:

     \input texinfo

   When the file is processed by TeX, the ‘\input texinfo’ command tells
TeX to load the macros needed for processing a Texinfo file.  These are
in a file called ‘texinfo.tex’, which should have been installed on your
system along with either the TeX or Texinfo software.  TeX uses the
backslash, ‘\’, to mark the beginning of a command, exactly as Texinfo
uses ‘@’.  The ‘texinfo.tex’ file causes the switch from ‘\’ to ‘@’;
before the switch occurs, TeX requires ‘\’, which is why it appears at
the beginning of the file.

   You may optionally follow this line with a comment to tell GNU Emacs
to use Texinfo mode when the file is edited:

     \input texinfo   @c -*-texinfo-*-

This may be useful when Emacs doesn't detect the file type from the file
extension automatically.


File: texinfo.info,  Node: @setfilename,  Next: @settitle,  Prev: First Line,  Up: Texinfo File Header

2.5.2 ‘@setfilename’: Set the Output File Name
----------------------------------------------

The ‘@setfilename’ line specifies the name of the output file to be
generated by ‘texi2any’.  This command is ignored for TeX formatting.
When present, it should be the first Texinfo command (that is, after
‘\input texinfo’).  Write the ‘@setfilename’ command at the beginning of
a line and follow it on the same line by the Info file name.

     @setfilename INFO-FILE-NAME

   The name must be different from the name of the Texinfo file.  There
are two conventions for choosing the name: you can either remove the
extension (such as ‘.texi’) entirely from the input file name, or
(recommended) replace it with the ‘.info’ extension.  It is not advised
to base the ‘@setfilename’ name on a entirely different name than the
input file name.

   When a ‘@setfilename’ line is present, the Texinfo processors ignore
everything written before the ‘@setfilename’ line.  This is why the very
first line of the file (the ‘\input’ line) does not show up in the
output.

   If there is no ‘@setfilename’ line, ‘texi2any’ uses the input file
name to determine the output name (*note Minimum::).  The ‘\input’ line
is still ignored in this processing, as well as leading blank lines.

   When producing another output format, ‘texi2any’ will replace any
final extension with the output format-specific extension (‘html’ when
generating HTML, for example), or add a dot followed by the extension
(‘.html’ for HTML) if the given name has no extension.

   @-commands are not allowed in ‘@setfilename’, except for ‘@@’, ‘@{’,
‘@}’ and associated @-commands such as ‘@atchar{}’.

   ‘@setfilename’ used to be required by the Texinfo processors and some
other programs.  This should not be the case any more; ‘@setfilename’
can be omitted.  If the Texinfo input is processed from standard input,
without an input file name to deduce the base file name from,
‘@setfilename’ could still be relevant.  This is not the only way,
however: ‘--output’ option specifies the output file name on the
‘texi2any’ command-line (*note Invoking texi2any::).

   Although an explicit ‘.info’ extension is preferable, some operating
systems cannot handle long file names.  You can run into a problem even
when the file name you specify is itself short enough.  This occurs
because the Info formatters split a long Info file into short indirect
subfiles, and name them by appending ‘-1’, ‘-2’, ..., ‘-10’, ‘-11’, and
so on, to the original file name.  (*Note Tag and Split Files::.)  The
subfile name ‘texinfo.info-10’, for example, is too long for old systems
with a 14-character limit on filenames; so the Info file name for this
document could be ‘texinfo’ rather than ‘texinfo.info’ on such a system.
‘@setfilename’ is a way to specify an alternative name.


File: texinfo.info,  Node: @settitle,  Next: Preamble,  Prev: @setfilename,  Up: Texinfo File Header

2.5.3 ‘@settitle’: Set the Document Title
-----------------------------------------

A Texinfo file should contain a line that looks like this:

     @settitle TITLE

   Write the ‘@settitle’ command at the beginning of a line and follow
it on the same line by the title.  Do not write anything else on the
line.  The ‘@settitle’ command should precede everything that generates
actual output.  The best place for it is right after the ‘@setfilename’
command, if present (described in the previous section).

   This command gives the title to use in a header or footer for
double-sided printed output, in case such headings are output.  For more
on headings for printed output, see *note Heading Generation::.

   In HTML, TITLE serves as the document ‘<title>’ and it becomes the
default document description in the ‘<head>’ part.

   When the title page is used in the output, as is generally the case
for printed output, the title in the ‘@settitle’ command does not affect
the title as it appears on the title page.  Thus, the two do not need
not to match exactly.  A practice we recommend is to include the version
or edition number of the manual in the ‘@settitle’ title; on the title
page, the version number generally appears as a ‘@subtitle’ so it would
be omitted from the ‘@title’.  *Note @titlepage::.


File: texinfo.info,  Node: Preamble,  Next: Start and End of Header,  Prev: @settitle,  Up: Texinfo File Header

2.5.4 Preamble
--------------

The “preamble” starts at the beginning of the Texinfo file and continues
until the first directly output material.  It typically includes the
file header (*note Texinfo File Header::), the ‘@copying’ block
specifying the document permissions (*note @copying::) and the
‘@titlepage’ specification (*note Titlepage & Copyright Page::).

   The preamble may contain commands that affect document formatting as
a whole but which do not produce output, or do not produce output
straight away, such as ‘@settitle’ (*note @settitle::),
‘@documentlanguage’, (*note @documentlanguage::), commands setting the
headings, controlling indentation or hyphenation, or the table of
contents (*note Contents::).

   Any text that starts a paragraph, @-commands that are formatted as
quotations, tables, lists and so on, and ‘@node’ (*note Nodes::) and
chapter structuring commands (*note Chapter Structuring::) end the
preamble.

   The concept of the preamble is significant for LaTeX output, as the
‘\begin{document}’ line is output at the end of the preamble.

   In plaintext, the preamble is simply output as usual at the beginning
of the document; for example, a ‘@contents’ in the preamble is output as
the table of contents (*note Contents::).

   There is not much special treatment of the preamble for HTML and Info
output either.  However, some settings current at the very end of the
preamble may be used for the document as a whole, regardless of what
follows.  This may apply to commands specifying the indentation, or the
language (*note @documentlanguage::).

   For example, for the following document, the HTML and Info copying
comments are formatted with ‘@documentlanguage’ set to ‘pt’, as it is
the last ‘@documentlanguage’ before the end of the preamble.

     \input texinfo
     @documentlanguage fr

     @copying
     The copying information @error{} some text
     @end copying

     @documentlanguage pt

     Text ending the preamble

     @documentlanguage de

     @node Top


File: texinfo.info,  Node: Start and End of Header,  Prev: Preamble,  Up: Texinfo File Header

2.5.5 Start and End of Header for Emacs
---------------------------------------

In Emacs, start- and end-of-header lines can be used to enclose commands
that globally affect the document in the Texinfo preambule.  This allows
you to format only part of a Texinfo file for Info or printing.  *Note
texinfo-format commands::.

   A start-of-header line is a Texinfo comment that looks like this:

     @c %**start of header

   Write the start-of-header line on the second line of a Texinfo file.
Follow the start-of-header commands that globally affect the document
formatting, such as ‘@settitle’, ‘@synindex’ or ‘@footnotestyle’; and
then by an end-of-header line.

   A end-of-header line is a Texinfo comment that looks like this:

     @c %**end of header

   The odd string of characters, ‘%**’, is to ensure that no other
comment is accidentally taken for a start-of-header line.  You can
change it if you wish by setting the ‘tex-start-of-header’ and/or
‘tex-end-of-header’ Emacs variables.  *Note Texinfo Mode Printing::.

   The start- and end-of-header lines are not part of the Texinfo format
specification, which is why they are implemented with comments.


File: texinfo.info,  Node: Directory Category,  Next: Document Permissions,  Prev: Texinfo File Header,  Up: Writing a Texinfo File

2.6 Directory Category
======================

Use the ‘@dircategory’ command to specify a category for the manual.
Here are a few examples of category names:

     Basics
     Text creation and manipulation
     Archiving
     Compression
     Database
     Editors
     Emacs
     Email
     Graphics
     Localization
     Network applications
     Printing
     Science
     Software development
     Software libraries
     Version control

   ‘@dircategory’ commands are usually followed by a ‘@direntry’ blocks,
which are used by ‘install-info’.  *Note Installing Dir Entries::, for
details.

   The first ‘@dircategory’ command in a manual is the category for the
entire manual.  Subsequent uses of ‘@dircategory’ set the category for
following ‘@direntry’ blocks only.


File: texinfo.info,  Node: Document Permissions,  Next: Titlepage & Copyright Page,  Prev: Directory Category,  Up: Writing a Texinfo File

2.7 Document Permissions
========================

This segment describes the document and contains the copyright notice
and copying permissions.  This is done with the ‘@copying’ command.  A
real manual includes more text here, according to the license under
which it is distributed.

     @copying
     This is a short example of a complete Texinfo file, version 1.0.

     Copyright @copyright{} 2016 Free Software Foundation, Inc.
     @end copying

   The copyright notice and copying permissions for a document need to
appear in several places in the various Texinfo output formats.
Therefore, Texinfo provides a command (‘@copying’) to declare this text
once, and another command (‘@insertcopying’) to insert the text at
appropriate points.

   If the document is a software manual, the software is typically under
a different license--for GNU and many other free software packages,
software is usually released under the GNU GPL, and manuals are released
under the GNU FDL.  It is helpful to state the license of the software
of the manual, but giving the complete text of the software license is
not necessarily required.

* Menu:

* @copying::                   Declare the document's copying permissions.
* @insertcopying::             Where to insert the permissions.


File: texinfo.info,  Node: @copying,  Next: @insertcopying,  Up: Document Permissions

2.7.1 ‘@copying’: Declare Copying Permissions
---------------------------------------------

The ‘@copying’ command should be given very early in the document; the
recommended location is right after the header material (*note Texinfo
File Header::).  It conventionally consists of a sentence or two about
what the program is, identification of the documentation itself, the
legal copyright line, and the copying permissions.  Here is a skeletal
example:

     @copying
     This manual is for PROGRAM (version VERSION, updated
     DATE), which ...

     Copyright @copyright{} YEARS COPYRIGHT-OWNER.

     @quotation
     Permission is granted to ...
     @end quotation
     @end copying

   The ‘@quotation’ has no legal significance; it's there to improve
readability in some contexts.

   The text of ‘@copying’ appears as a comment at the beginning of Info
and HTML output files.  This information is also output at the beginning
of the DocBook output files using appropriate markup.  It is _not_
output implicitly in plain text or printed output; it's up to you to use
‘@insertcopying’ to emit the copying information.  See the next section
for details.

   The ‘@copyright{}’ command generates a ‘c’ inside a circle when the
output format supports this glyph (print and HTML always do, for
instance).  When the glyph is not supported in the output, it generates
the three-character sequence ‘(C)’.

   The copyright notice itself has the following legally-prescribed
form:

     Copyright © YEARS COPYRIGHT-OWNER.

   The word 'Copyright' must always be written in English, even if the
document is otherwise written in another language.  This is due to
international law.

   The list of years should include all years in which a version was
completed (even if it was released in a subsequent year).  It is
simplest for each year to be written out individually and in full,
separated by commas.

   The copyright owner (or owners) is whoever holds legal copyright on
the work.  In the case of works assigned to the FSF, the owner is 'Free
Software Foundation, Inc.'.

   The copyright 'line' may actually be split across multiple lines,
both in the source document and in the output.  This often happens for
documents with a long history, having many different years of
publication.  If you do use several lines, do not indent any of them (or
anything else in the ‘@copying’ block) in the source file.

   *Note (maintain)Copyright Notices::, for additional information.
*Note GNU Sample Texts::, for the full text to be used in GNU manuals.
*Note GNU Free Documentation License::, for the license itself under
which GNU and other free manuals are distributed.


File: texinfo.info,  Node: @insertcopying,  Prev: @copying,  Up: Document Permissions

2.7.2 ‘@insertcopying’: Include Permissions Text
------------------------------------------------

The ‘@insertcopying’ command is simply written on a line by itself, like
this:

     @insertcopying

   This inserts the text previously defined by ‘@copying’.  To meet
legal requirements, it must be used on the copyright page in the printed
manual (*note Copyright::).

   The ‘@copying’ command itself causes the permissions text to appear
in an Info file _before_ the first node.  The text is also copied into
the beginning of each split Info output file, as is legally necessary.
This location implies a human reading the manual using Info does _not_
see this text (except when using the advanced Info command ‘g *’).  This
does not matter for legal purposes, because the text is present.  But to
get a visible text in the output, ‘@insertcopying’ should be used.

   Similarly, the ‘@copying’ text is automatically included at the
beginning of each HTML output file, as an HTML comment.  Again, this
text is not visible without ‘@insertcopying’ (unless the reader views
the HTML source).

   The permissions text defined by ‘@copying’ also appears automatically
at the beginning of the DocBook output files using appropriate markup.
‘@insertcopying’ can be used to output the permission text within normal
text.


File: texinfo.info,  Node: Titlepage & Copyright Page,  Next: Contents,  Prev: Document Permissions,  Up: Writing a Texinfo File

2.8 Title and Copyright Pages
=============================

In hard copy output, the manual's name and author are usually printed on
a title page.  Copyright information is usually printed on the back
(verso) of the title page.  This segment must be enclosed between
‘@titlepage’ and ‘@end titlepage’ commands:

     @titlepage
     @title Sample Title

     @c The following two commands start the copyright page.
     @page
     @vskip 0pt plus 1filll
     @insertcopying
     @end titlepage

We use the ‘@insertcopying’ command to include the permission text from
the previous section, instead of writing it out again.

   The title and copyright pages appear in printed manuals, but not in
most other output formats.  In HTML, the best way to get a title page
similar to printed manuals is to set the ‘NO_TOP_NODE_OUTPUT’
customization variable (*note NO_TOP_NODE_OUTPUT::).

* Menu:

* @titlepage::                 Create a title for the printed document.
* @title @subtitle @author::   The ‘@title’, ‘@subtitle’, and ‘@author’
                               commands.
* @titlefont @center @sp::     The ‘@titlefont’, ‘@center’, and ‘@sp’ commands.
* Copyright::                  How to write the copyright notice and include
                               copying permissions.
* Heading Generation::         Turn on page headings after the title and
                               copyright pages.


File: texinfo.info,  Node: @titlepage,  Next: @title @subtitle @author,  Up: Titlepage & Copyright Page

2.8.1 ‘@titlepage’
------------------

Start the material for the title page and following copyright page with
‘@titlepage’ on a line by itself and end it with ‘@end titlepage’ on a
line by itself.

   The ‘@end titlepage’ command starts a new page and turns on page
numbering (*note Heading Generation::).  All the material that you want
to appear on unnumbered pages should be put between the ‘@titlepage’ and
‘@end titlepage’ commands.

   By using the ‘@page’ command, you can force a page break within the
region delineated by the ‘@titlepage’ and ‘@end titlepage’ commands and
thereby create more than one unnumbered page.  This is how the copyright
page is produced.  (The ‘@titlepage’ command might perhaps have been
better named the ‘@titleandadditionalpages’ command, but that would have
been rather long!)

   When you write a manual about a computer program, you should write
the version of the program to which the manual applies on the title
page.  If the manual changes more frequently than the program or is
independent of it, you should also include an edition number(1) for the
manual.  This helps readers keep track of which manual is for which
version of the program.  (The 'Top' node should also contain this
information; see *note The Top Node::.)

   One method uses the ‘@title’, ‘@subtitle’, and ‘@author’ commands to
create a title page.  With this method, you do not specify any of the
actual formatting of the title page.  You specify the text you want, and
Texinfo does the formatting.  The usual formatting consist of black
rules under the title and author lines and the subtitle text set flush
to the right-hand side of the page.

   Texinfo also provides a second method for creating a title page.
using typesetting commands that are not to be used in the main text.
This method uses uses the ‘@titlefont’, ‘@sp’, and ‘@center’ commands to
generate a title page in which the words on the page are centered.

   For sufficiently simple documents, and for the bastard title page in
traditional book frontmatter, Texinfo also provides a command
‘@shorttitlepage’ which takes the rest of the line as the title.  The
argument is typeset on a page by itself and followed by a blank page.
In HTML, ‘@shorttitlepage’ can play the same role as ‘@settitle’, if
‘@settitle’ is not set.  *Note @settitle::.

   ---------- Footnotes ----------

   (1) We have found that it is helpful to refer to versions of
independent manuals as 'editions' and versions of programs as
'versions'; otherwise, we find we are liable to confuse each other in
conversation by referring to both the documentation and the software
with the same words.


File: texinfo.info,  Node: @title @subtitle @author,  Next: @titlefont @center @sp,  Prev: @titlepage,  Up: Titlepage & Copyright Page

2.8.2 ‘@title’, ‘@subtitle’, and ‘@author’
------------------------------------------

You can use the ‘@title’, ‘@subtitle’, and ‘@author’ commands to create
a title page in which the vertical and horizontal spacing is done for
you automatically.

   Write the ‘@title’, ‘@subtitle’, or ‘@author’ commands at the
beginning of a line followed by the title, subtitle, or author.  The
‘@author’ command may be used for a quotation in an ‘@quotation’ block
(*note @quotation::); except for that, it is an error to use any of
these commands outside of ‘@titlepage’.

   The ‘@title’ command normally produces a line in which the title is
set flush to the left-hand side of the page in a larger than normal
font.  The title is underlined with a black rule.  The title must be
given on a single line in the source file; it will be broken into
multiple lines of output is needed.

   For long titles, the ‘@*’ command may be used to specify the line
breaks in long titles if the automatic breaks do not suit.  Such
explicit line breaks are generally reflected in all output formats; if
you only want to specify them for the printed output, use a conditional
(*note Conditionals::).  For example:

     @title This Long Title@inlinefmt{tex,@*} Is Broken in @TeX{}

   The ‘@subtitle’ command normally sets subtitles in a normal-sized
font flush to the right-hand side of the page.

   The ‘@author’ command normally sets the names of the author or
authors in a middle-sized font flush to the left-hand side of the page
on a line near the bottom of the title page.  The names are followed by
a black rule that is thinner than the rule that normally underlines the
title.

   There are two ways to use the ‘@author’ command: you can write the
name or names on the remaining part of the line that starts with an
‘@author’ command:

     @author by Jane Smith and John Doe

or you can write the names one above each other by using multiple
‘@author’ commands:

     @author Jane Smith
     @author John Doe

   A template for this method looks like this:

     @titlepage
     @title NAME-OF-MANUAL-WHEN-PRINTED
     @subtitle SUBTITLE-IF-ANY
     @subtitle SECOND-SUBTITLE
     @author AUTHOR
     @page
     ...
     @end titlepage


File: texinfo.info,  Node: @titlefont @center @sp,  Next: Copyright,  Prev: @title @subtitle @author,  Up: Titlepage & Copyright Page

2.8.3 ‘@titlefont’, ‘@center’, and ‘@sp’
----------------------------------------

You can also use the ‘@titlefont’, ‘@sp’, and ‘@center’ commands to
create a title page for a printed document.

   Use the ‘@titlefont’ command to select a large font suitable for the
title itself.  You can use ‘@titlefont’ more than once if you have an
especially long title.

   For HTML output, each ‘@titlefont’ command produces an ‘<h1>’
heading, but the HTML document ‘<title>’ is not affected.  For that, you
could put a ‘@settitle’ command before the ‘@titlefont’ command (*note
@settitle::).

   For example:

     @titlefont{Texinfo}

   Use the ‘@center’ command at the beginning of a line to center the
remaining text on that line.  Thus,

     @center @titlefont{Texinfo}

centers the title, which in this example is "Texinfo" printed in the
title font.

   Use the ‘@sp’ command to insert vertical space.  For example:

     @sp 2

This inserts two blank lines on the printed page.  (*Note @sp::, for
more information about the ‘@sp’ command.)

   A template for this method looks like this:

     @titlepage
     @sp 10
     @center @titlefont{NAME-OF-MANUAL-WHEN-PRINTED}
     @sp 2
     @center SUBTITLE-IF-ANY
     @sp 2
     @center AUTHOR
     ...
     @end titlepage

   The spacing of the example fits an 8.5 by 11 inch manual.


File: texinfo.info,  Node: Copyright,  Next: Heading Generation,  Prev: @titlefont @center @sp,  Up: Titlepage & Copyright Page

2.8.4 Copyright Page
--------------------

By international treaty, the copyright notice for a book must be either
on the title page or on the back of the title page.  When the copyright
notice is on the back of the title page, that page is customarily not
numbered.  Therefore, in Texinfo, the information on the copyright page
should be within ‘@titlepage’ and ‘@end titlepage’ commands.

   Use the ‘@page’ command to cause a page break.  To push the copyright
notice and the other text on the copyright page towards the bottom of
the page, use the following incantation after ‘@page’:

     @vskip 0pt plus 1filll

The ‘@vskip’ command inserts whitespace in the TeX output; it is ignored
in all other output formats.  The ‘0pt plus 1filll’ means to put in zero
points of mandatory whitespace, and as much optional whitespace as
needed to push the following text to the bottom of the page.  Note the
use of three ‘l’s in the word ‘filll’; this is correct.

   To insert the copyright text itself, write ‘@insertcopying’ next
(*note Document Permissions::):

     @insertcopying

   Follow the copying text by the publisher, ISBN numbers, cover art
credits, and other such information.

   Here is an example putting all this together:

     @titlepage
     ...
     @page
     @vskip 0pt plus 1filll
     @insertcopying

     Published by ...

     Cover art by ...
     @end titlepage

   We have one more special case to consider: for plain text output, you
must insert the copyright information explicitly if you want it to
appear.  For instance, you could have the following after the copyright
page:

     @ifplaintext
     @insertcopying
     @end ifplaintext

   You could include other title-like information for the plain text
output in the same place.


File: texinfo.info,  Node: Heading Generation,  Prev: Copyright,  Up: Titlepage & Copyright Page

2.8.5 Heading Generation
------------------------

Texinfo has two standard page heading formats, one for documents printed
on one side of each sheet of paper (single-sided printing), and the
other for documents printed on both sides of each sheet (double-sided
printing).

   In full generality, you can control the headings in different ways:

   • The conventional way is to write a ‘@setchapternewpage’ command
     before the title page commands.

     Most documents are formatted with the standard single-sided or
     double-sided headings, (sometimes) using ‘@setchapternewpage odd’
     for double-sided printing and (almost always) no
     ‘@setchapternewpage’ command for single-sided printing (*note
     @setchapternewpage::).

   • Alternatively, you can use the ‘@headings’ command to prevent page
     headings from being generated or to start them for either single or
     double-sided printing.  To turn off headings, write ‘@headings
     off’.  *Note @headings::.

   • Or, you may specify your own page heading and footing format.
     *Note Headings::.


File: texinfo.info,  Node: Contents,  Next: The Top Node,  Prev: Titlepage & Copyright Page,  Up: Writing a Texinfo File

2.9 Generating a Table of Contents
==================================

The ‘@chapter’, ‘@section’, and other structuring commands (*note
Chapter Structuring::) supply the information to make up a table of
contents, but they do not cause an actual table to appear in the manual.
To do this, you must use the ‘@contents’ and/or ‘@summarycontents’
command(s).

‘@contents’
     Generates a table of contents in a printed manual, including all
     chapters, sections, subsections, etc., as well as appendices and
     unnumbered chapters.  Headings generated by ‘@majorheading’,
     ‘@chapheading’, and the other ‘@...heading’ commands do not appear
     in the table of contents (*note Structuring Command Types::).

‘@shortcontents’
‘@summarycontents’
     (‘@summarycontents’ is a synonym for ‘@shortcontents’.)

     Generates a short or summary table of contents that lists only the
     chapters, appendices, and unnumbered chapters.  Sections,
     subsections and subsubsections are omitted.  Only a long manual
     needs a short table of contents in addition to the full table of
     contents.

   Both contents commands should be written on a line by themselves, and
placed near the beginning of the file, after the ‘@end titlepage’ (*note
@titlepage::), before any sectioning command.  The contents commands
automatically generate a chapter-like heading at the top of the first
table of contents page, so don't include any sectioning command such as
‘@unnumbered’ before them.

   Since an Info file uses menus instead of tables of contents, the Info
formatting commands ignore the contents commands.  But the contents are
included in plain text output and in other output formats, such as HTML.

   In HTML output, the links in the short table of contents point to
corresponding entries in the full table of contents rather than the text
of the document.  The links in the full table of contents point to the
main text of the document.

   ‘@shortcontents’ is not implemented for LaTeX output.


File: texinfo.info,  Node: The Top Node,  Next: The Body of the Document,  Prev: Contents,  Up: Writing a Texinfo File

2.10 The 'Top' Node and Master Menu
===================================

The 'Top' node is the node in which a reader enters an Info manual.  As
such, it should contain a very brief description of the manual
(including the version number).  The contents of the 'Top' node do not
appear in printed output nor in DocBook output.

   It is conventional to write a line with a ‘@top’ command containing
the title of the document immediately after the ‘@node Top’ line (*note
@top Command::).

   We repeat the short description from the beginning of the ‘@copying’
text, but there's no need to repeat the copyright information, so we
don't use ‘@insertcopying’ here.

   The 'Top' node contains a top-level “menu” listing the chapters, and
possibly a “detailed menu” listing all the nodes in the entire document.

     @node Top
     @top Short Sample

     This is a short sample Texinfo file.

     @menu
     * First Chapter::    The first chapter is the
                            only chapter in this sample.
     * Index::            Complete index.
     @end menu

* Menu:

* Master Menu Parts::


File: texinfo.info,  Node: Master Menu Parts,  Up: The Top Node

2.10.1 Parts of a Master Menu
-----------------------------

A “master menu” is the main menu.  It is customary to include a detailed
menu listing all the nodes in the document in this menu.  Like any other
menu, a master menu is enclosed in ‘@menu’ and ‘@end menu’ and does not
appear in the printed output nor in DocBook output.

   The master menu contains entries for the major nodes in the Texinfo
file: the nodes for the chapters, chapter-like sections, and the
appendices, followed by nodes for the indices.

   You may choose to follow these entries with a “detailed menu”.  This
lists other, lower-level nodes, often ordered by chapter.  These items
may be a convenience for an inquirer who can go directly to a particular
node when searching for specific information, rather than going through
an intermediate menu.  If you use a detailed menu in your master menu,
mark it with the ‘@detailmenu ... @end detailmenu’ environment.

   Each section in the menu can be introduced by a descriptive line.  So
long as the line does not begin with an asterisk, it will not be treated
as a menu entry.  (*Note Writing a Menu::, for more information.)

   For example, the master menu for this manual looks like the following
(but has many more entries):

     @menu
     * Copying Conditions::  Your rights.
     * Overview::            Texinfo in brief.
     ...
     * Command and Variable Index::
     * General Index::

     @detailmenu
     --- The Detailed Node Listing ---

     Overview of Texinfo

     * Reporting Bugs:: ...
     ...

     Beginning a Texinfo File

     * Sample Beginning:: ...
     ...
     @end detailmenu
     @end menu


File: texinfo.info,  Node: The Body of the Document,  Next: Ending a File,  Prev: The Top Node,  Up: Writing a Texinfo File

2.11 The Body of the Document
=============================

The body segment contains all the text of the document.  A manual is
divided into one or more “nodes” (*note Nodes::).  The example
illustrates a chapter made of three nodes, one for introductory material
in the chapter, and two sections.  The introductory material contains an
enumerated list.

     @node First Chapter
     @chapter First Chapter

     @cindex chapter, first
     This is the first chapter.
     @cindex index entry, another

     Here is a numbered list.

     @enumerate
     @item
     This is the first item.

     @item
     This is the second item.
     @end enumerate


     @node First Section
     @section First Section

     First section of first chapter.


     @node Second Section
     @section Second Section

     Second section of first chapter.

   In the Info output, the ‘First Chapter’ node will contain a menu
listing the two sections in the chapter.  Similarly, when this node is
output in its own HTML file, it will contain a table of contents for the
chapter.

   Here is what the contents of this chapter will look like:


     1. First Chapter
     ****************

     This is the first chapter.

     Here is a numbered list.

       1. This is the first item.

       2. This is the second item.

     1.1 First Section
     =================

     First section of first chapter.

     1.2 Second Section
     ==================

     Second section of first chapter.

(In the Info and HTML output, the chapter would also be split into
nodes.)


File: texinfo.info,  Node: Ending a File,  Prev: The Body of the Document,  Up: Writing a Texinfo File

2.12 Ending a Texinfo File
==========================

The end of a Texinfo file should include commands to create indices
(*note Printing Indices & Menus::), and the ‘@bye’ command to mark the
last line to be processed.  For example:

     @node Index
     @unnumbered Index

     @printindex cp

     @bye

   A ‘@bye’ command terminates Texinfo processing.  It should be on a
line by itself.  Anything following ‘@bye’ is completely ignored.


File: texinfo.info,  Node: Nodes,  Next: Chapter Structuring,  Prev: Writing a Texinfo File,  Up: Top

3 Nodes
*******

A “node” is a region of text that begins at a ‘@node’ command, and
continues until the next ‘@node’ command.  To specify a node, write a
‘@node’ command at the beginning of a line, and follow it with the name
of the node.  Info readers display one node at a time, and provide
commands for the user to move to related nodes.  The HTML output can be
similarly navigated.

   Nodes are used as the targets of cross-references.  Cross-references,
such as the one at the end of this sentence, are made with ‘@xref’ and
related commands; see *note Cross References::.  Cross-references can be
sprinkled throughout the text.  Other @-commands may also be the target
of cross-references (*note @anchor::, *note Floats::).

   Normally, you put a node command immediately before each chapter
structuring command--for example, an ‘@section’ or ‘@subsection’ line.
(*Note Chapter Structuring::.)  You should do this even if you do not
intend to format the file for Info.  This is because printed output uses
both ‘@node’ names and chapter-structuring names in the output for
cross-references.  The only time you are likely to use the chapter
structuring commands without also using nodes is if you are writing a
document that contains no cross references and will only be printed, not
transformed into Info, HTML, or other formats.

* Menu:

* Writing a Node::             How to write a ‘@node’ line.
* Node Names::                 How to choose node names.
* Node Line Requirements::     Keep names unique.
* First Node::                 How to write a 'Top' node.
* @top Command::               How to use the ‘@top’ command.
* Texinfo Document Structure:: Double structure of documents.
* Node Menu Illustration::     A diagram, and sample nodes and menus.
* Node Descriptions::          ‘@nodedescription’ and ‘@nodedescriptionblock’.
* Menus::                      Listing subordinate nodes.


File: texinfo.info,  Node: Writing a Node,  Next: Node Names,  Up: Nodes

3.1 Writing a ‘@node’ Line
==========================

Write ‘@node’ at the beginning of a line followed by the name of the
node, like this:

     @node NODE-NAME

   After you have inserted a ‘@node’ line, you should immediately write
the @-command for the associated chapter or section (if any) and insert
its name.

   You may optionally follow the node name argument to ‘@node’ with up
to three optional arguments on the rest of the same line, separating the
arguments with commas.  These are the names of the 'Next', 'Previous',
and 'Up' pointers, in that order.  Hence, the template for a
fully-written-out node line with 'Next', 'Previous', and 'Up' pointers
looks like this:

     @node NODE-NAME, NEXT, PREVIOUS, UP

   The NODE-NAME argument must be present, but the others are optional.
If you wish to specify some but not others, just insert commas as
needed, as in: ‘@node mynode,,,uppernode’.  Any spaces before or after
each name on the ‘@node’ line are ignored.  However, if your Texinfo
document is hierarchically organized, as virtually all are, we recommend
leaving off all the pointers and letting ‘texi2any’ determine them.

   The ‘texi2any’ program automatically determines node pointers for a
hierarchically organized document.  For it to do this, each ‘@node’
command should be followed immediately by a sectioning command such as
‘@chapter’ or ‘@section’ (except that comment lines may intervene).
Finally, you must follow the 'Top' ‘@node’ line with a line beginning
with ‘@top’ to mark the top-level node in the file.  *Note @top
Command::.

   Even when you explicitly specify all pointers, you cannot write the
nodes in the Texinfo source file in an arbitrary order.  You must write
the nodes in the order you wish them to appear in the output.  For Info
format one can imagine that the order may not matter, but it matters for
the other formats.

   In most cases, you will want to take advantage of the pointer
creation feature, and not redundantly specify node pointers that the
programs can determine.  However, Texinfo documents are not required to
be organized hierarchically or in fact to contain sectioning commands at
all (for example, if you never intend the document to be printed), so
node pointers may still be specified explicitly, in full generality.

   If you are using GNU Emacs, and want explicit pointers, you can use
the update node commands provided by Texinfo mode to insert the names of
the pointers.  (*Note Updating Nodes and Menus::.)

   Alternatively, you can insert the 'Next', 'Previous', and 'Up'
pointers yourself.  If you do this in Emacs, you may find it helpful to
use the Texinfo mode keyboard command ‘C-c C-c n’.  This command inserts
‘@node’ and a comment line listing the names of the pointers in their
proper order.  The comment line helps you keep track of which arguments
are for which pointers.


File: texinfo.info,  Node: Node Names,  Next: Node Line Requirements,  Prev: Writing a Node,  Up: Nodes

3.2 Choosing Node Names
=======================

The name of a node identifies the node.  For all the details of node
names, *note Node Line Requirements::).

   Here are some suggestions for node names:

   • Try to pick node names that are informative but short.

     In the Info file, the file name, node name, and pointer names are
     all inserted on one line, which may run into the right edge of the
     window.  (This does not cause a problem with Info, but is ugly.)

   • Try to pick node names that differ from each other near the
     beginnings of their names.  This way, it is easy to use automatic
     name completion in Info.

   • Conventionally, node names are capitalized in the same way as
     section and chapter titles.  In this manual, initial and
     significant words are capitalized; others are not.  In other
     manuals, just initial words and proper nouns are capitalized.
     Either way is fine; we recommend just being consistent.

   • In HTML output, any characters in the node name other than plain
     ASCII letters, numbers or spaces will be changed in the file name.
     (*Note HTML Xref Node Name Expansion::.)  This can make the URLs
     for the pages in your manual less user-friendly; for example, in
     this manual the ‘@dots’ node is output as ‘__0040dots.html’.

   Because node names are used in cross-references, it is not desirable
to casually change them once published.  When you delete or rename a
node, it is usually a good idea to define an ‘@anchor’ with the old
name.  That way, references from other manuals, from mail archives, and
so on are not invalidated.  *Note @anchor::.

   The pointers from a given node enable you to reach other nodes and
consist simply of the names of those nodes.

   Normally, a node's 'Up' pointer contains the name of the node whose
menu mentions that node.  The node's 'Next' pointer contains the name of
the node that follows the present node in that menu and its 'Previous'
pointer contains the name of the node that precedes it in that menu.
When a node's 'Previous' node is the same as its 'Up' node, both
pointers name the same node.

   Usually, the first node of a Texinfo file is the 'Top' node, and its
'Up' pointer points to the ‘dir’ file, which contains the main menu for
all of Info.


File: texinfo.info,  Node: Node Line Requirements,  Next: First Node,  Prev: Node Names,  Up: Nodes

3.3 ‘@node’ Line Requirements
=============================

Names used with ‘@node’ have several requirements:

   • All the node names in a single Texinfo file must be unique.

     This means, for example, that if you end every chapter with a
     summary, you must name each summary node differently.  You cannot
     just call them all "Summary".  You may, however, duplicate the
     titles of chapters, sections, and the like.  Thus you can end each
     chapter with a section called "Summary", so long as the node names
     for those sections are all different.

     Node names, anchor names (*note @anchor::), and float labels (*note
     @float::) must all be unique.

   • Node names can contain @-commands(1).  For example, using ‘@TeX{}’
     in a node name results in the TeX logo being output, as it would be
     in normal text.  Cross-references should use ‘@TeX{}’ just as the
     node name does.

     Some commands do not make sense in node names; for instance,
     environments (e.g., ‘@quotation’), commands that read a whole line
     as their argument (e.g., ‘@sp’), and plenty of others.  For the
     complete list of commands that are allowed, and their expansion for
     HTML identifiers and file names, *note HTML Xref Command
     Expansion::.

   • A node name may not start with a left parenthesis preceding a right
     parenthesis, as in ‘(not)allowed’, since this syntax is used to
     specify an external manual.

   • Unfortunately, you cannot reliably use periods, commas, or colons
     within a node name; these can confuse some Info readers.
     ‘texi2any’ quotes problematic node names and labels by default, but
     some Info readers do not recognize this syntax.  Node name and
     label quoting causes ‘DEL’ characters (‘CTRL-?’, character number
     127, often rendered as ‘^?’) to appear around the name.  To remove
     node names and labels quoting, you can set the customization
     variable ‘INFO_SPECIAL_CHARS_QUOTE’ to ‘0’ (*note Info and
     Plaintext Customization Variables::).

     ‘texi2any’ warns about such problematic usage in node names, menu
     items, and cross-references.  If you don't want to see the
     warnings, you can set the customization variable
     ‘INFO_SPECIAL_CHARS_WARNING’ to ‘0’ (*note Info and Plaintext
     Customization Variables::).

     If you insist on using these characters in node names, in order not
     to confuse the Texinfo processors you must still escape those
     characters, by using either special insertions (*note Inserting a
     Comma::) or ‘@asis’ (*note @asis::).  For example:

          @node foo@asis{::}bar@comma{} baz

     As an example of avoiding the special characters, the following is
     a section title in this manual:

          @section @code{@@unnumbered}, @code{@@appendix}: Chapters with...

     But the corresponding node name lacks the commas and the subtitle:

          @node @code{@@unnumbered @@appendix}

   • Case is significant in node names.

   • Spaces before and after names on the ‘@node’ line are ignored.
     Multiple whitespace characters "inside" a name are collapsed to a
     single space.  For example:

          @node foo bar
          @node  foo bar,
          @node foo bar ,
          @node foo  bar,
          @node  foo  bar ,

     all define the same node, namely ‘foo bar’.  In menu entries, a
     single internal space should be used in node names or some versions
     of some Info readers will not find the node.

   ---------- Footnotes ----------

   (1) Prior to the Texinfo 5 release in 2013, this feature was
supported in an ad hoc way (the ‘--commands-in-node-names’ option to
‘makeinfo’).  Now it is part of the language.


File: texinfo.info,  Node: First Node,  Next: @top Command,  Prev: Node Line Requirements,  Up: Nodes

3.4 The First Node
==================

The first node of a Texinfo file is the “Top” node, except in an
included file (*note Include Files::).  The Top node should contain a
short summary and a master menu.  *Note The Top Node:: for more
information on the Top node contents and examples.  Straight text before
the Top node outside of any node should be avoided.  Such text, if
present, is not output for DocBook.

   Here is a description of the node pointers to be used in the Top
node:

   • The Top node (which must be named ‘top’ or ‘Top’) should have as
     its 'Up' node the name of a node in another file, where there is a
     menu that leads to this file.  Specify the file name in
     parentheses.

     Usually, all Info files are available through a single virtual Info
     tree, constructed from multiple directories.  In this case, use
     ‘(dir)’ as the parent of the Top node; this specifies the top-level
     node in the ‘dir’ file, which contains the main menu for the Info
     system as a whole.  (Each directory with Info files is intended to
     contain a file named ‘dir’.)

     That's fine for Info, but for HTML output, one might well want the
     Up link from the Top node to go to some specific place.  For
     example, for GNU the natural place would be
     <http://www.gnu.org/manual/> (a web page collecting links to most
     GNU manuals), better specified as just ‘/manual/’ if the manual
     will be installed on ‘www.gnu.org’.  This can be specified with the
     ‘TOP_NODE_UP_URL’ customization variable (*note File Names and
     Links Customization for HTML::), as in

          $ texi2any --html -c TOP_NODE_UP_URL=/manual/ ...

   • The 'Prev' node of the Top node is usually omitted.

   • The 'Next' node of the Top node should be the first chapter in your
     document.

   *Note Installing an Info File::, for more information about
installing an Info file in the ‘info’ directory.

   It is usually best to leave the pointers off entirely and let the
tools implicitly define them, with this simple result:

     @node Top


File: texinfo.info,  Node: @top Command,  Next: Texinfo Document Structure,  Prev: First Node,  Up: Nodes

3.5 The ‘@top’ Sectioning Command
=================================

The ‘@top’ command is a special sectioning command that you should only
use after a ‘@node Top’ line at the beginning of a Texinfo file.

   It produces the same sort of output as ‘@unnumbered’ (*note
@unnumbered @appendix::).  In LaTeX ‘\part*’ is used.

   ‘@top’ is ignored when raising or lowering sections.  That is, it is
never lowered and nothing can be raised to it (*note Raise/lower
sections::).

   It used to be conventional to wrap the ‘Top’ node in an ‘@ifnottex’
conditional so that it would not appear in printed output (*note
Conditionals::).  Thus, a Top node often looked like this:

     @ifnottex
     @node Top
     @top YOUR-MANUAL-TITLE

     VERY-HIGH-LEVEL-SUMMARY
     @end ifnottex

   This is no longer necessary, as the ‘Top’ node is now never output
for printed output.  The ‘Top’ node is not output for DocBook either.


File: texinfo.info,  Node: Texinfo Document Structure,  Next: Node Menu Illustration,  Prev: @top Command,  Up: Nodes

3.6 Texinfo Document Structure
==============================

Nodes can contain “menus”, which contain the names of “child nodes”
within the parent node; for example, a node corresponding to a chapter
would have a menu of the sections in that chapter.  The menus allow the
user to move to the child nodes in the Info output.

   In addition, nodes contain “node pointers” that name other nodes.
The 'Next' and 'Previous' pointers link nodes at the same sectioning
level into a chain.  As you might imagine, the 'Next' pointer links to
the next node, and the 'Previous' pointer links to the previous node.
In general, 'Next' and 'Previous' refer to nodes at the _same
hierarchical level_ in the manual, not necessarily to the next node
within the Texinfo file.  In the Texinfo file, the subsequent node may
be at a lower level--a section-level node most often follows a
chapter-level node, for example.  Thus, for example, all the nodes that
are at the level of sections within a chapter are linked together, and
the order in this chain is the same as the order of the children in the
menu of the parent chapter.  Each child node records the parent node
name as its 'Up' pointer.

   Since the 'Top' node is the only node at that level, 'Next' refers to
the first following node, which is almost always a chapter or
chapter-level node.  This is an exception to the rule of 'Next' being at
the same hierarchical level.

   The Info and HTML output for each node includes links to the 'Next',
'Previous', and 'Up' nodes.  The HTML also uses the ‘accesskey’
attribute with the values ‘n’, ‘p’, and ‘u’ respectively.  This allows
people using web browsers to follow the navigation using (typically)
‘M-LETTER’, e.g., ‘M-n’ for the 'Next' node, from anywhere within the
node.  Node pointers and menus provide structure for Info files just as
chapters, sections, subsections, and the like provide structure for
printed books.  The two structures are theoretically distinct; in
practice, however, the tree structure of printed books is essentially
always used for the node and menu structure also, as this leads to a
document which is easy to follow.

   Typically, the sectioning structure and the node structure are
completely parallel, with one node for each chapter, section, etc., and
with the nodes following the same hierarchical arrangement as the
sectioning.  Thus, if a node is at the logical level of a chapter, its
child nodes are at the level of sections; similarly, the child nodes of
sections are at the level of subsections.

   It is technically possible to create Texinfo documents with only one
structure or the other, or for the two structures not to be parallel, or
for either the sectioning or node structure to be different from the
conventional structure.  To the best of our knowledge, however, all the
Texinfo manuals currently in general use do follow the conventional
parallel structure.


File: texinfo.info,  Node: Node Menu Illustration,  Next: Node Descriptions,  Prev: Texinfo Document Structure,  Up: Nodes

3.7 Node and Menu Illustration
==============================

Here is a diagram that illustrates a Texinfo file with three chapters,
each of which contains two sections.

   The "root" is at the top of the diagram and the "leaves" are at the
bottom.  This is how such a diagram is drawn conventionally; it
illustrates an upside-down tree.  For this reason, the root node is
called the 'Top' node, and 'Up' node pointers carry you closer to the
root.

                              Top
                               |
             -------------------------------------
            |                  |                  |
         Chapter 1          Chapter 2          Chapter 3
            |                  |                  |
         --------           --------           --------
        |        |         |        |         |        |
     Section  Section   Section  Section   Section  Section
       1.1      1.2       2.1      2.2       3.1      3.2

   Using explicit pointers (not recommended, but shown for purposes of
the example), the fully-written command to start Chapter 2 would be
this:

     @node     Chapter 2,  Chapter 3, Chapter 1, Top
     @comment  node-name,  next,      previous,  up

This ‘@node’ line says that the name of this node is "Chapter 2", the
name of the 'Next' node is "Chapter 3", the name of the 'Previous' node
is "Chapter 1", and the name of the 'Up' node is "Top".  You can (and
should) omit writing out these node names if your document is
hierarchically organized, but the pointer relationships still obtain.

   To go to Sections 2.1 and 2.2 using Info, you need a menu inside
Chapter 2.  (*Note Menus::.)  You would write the menu just before the
beginning of Section 2.1, like this:

        @menu
        * Sect. 2.1::    Description of this section.
        * Sect. 2.2::    Description.
        @end menu

   The automatic pointers for the node for Sect. 2.1 correspond to:

     @node     Sect. 2.1, Sect. 2.2, ,         Chapter 2
     @comment  node-name, next,      previous, up

   Note that no 'Prev' pointer is generated, since there is no other
node at the same hierarchical level before Sect. 2.1.

   Using explicit pointers, the node for Sect. 2.1 could be written like
this:

     @node     Sect. 2.1, Sect. 2.2, Chapter 2, Chapter 2
     @comment  node-name, next,      previous,  up

   With automatic pointers, the 'Next' and 'Previous' pointers of a node
lead to other nodes at the same level--from chapter to chapter or from
section to section.  As shown, when using explicit pointers, the
pointers can also lead somewhere else, here, for example, the 'Previous'
pointer points up.  An 'Up' pointer usually leads to a node at the level
above (closer to the 'Top' node; and a 'Menu' leads to nodes at a level
below (closer to 'leaves').  (A cross-reference can point to a node at
any level; see *note Cross References::.)

   Technically, explicit node pointers can carry you to any node,
regardless of the structure of the document; even to nodes in a
different Info file.  However, it would be very confusing for readers to
have the 'Next', 'Previous' and 'Up' pointers lead to nodes that do not
correspond, even loosely, to the next, previous and up node.

   A ‘@node’ command and a chapter structuring command are
conventionally used together, in that order, often followed by indexing
commands.  (As shown in the example above, you may follow the ‘@node’
line with a comment line, e.g., to show which pointer is which if
explicit pointers are used.)  The Texinfo processors use this construct
to determine the relationships between nodes and sectioning commands.

   Here is the beginning of the chapter in this manual called "Ending a
Texinfo File".  This shows a ‘@node’ line followed by a ‘@chapter’ line,
and then by indexing lines.

     @node Ending a File
     @chapter Ending a Texinfo File
     @cindex Ending a Texinfo file
     @cindex Texinfo file ending
     @cindex File ending


File: texinfo.info,  Node: Node Descriptions,  Next: Menus,  Prev: Node Menu Illustration,  Up: Nodes

3.8 Node Descriptions
=====================

You can provide a short description of the purpose of a node by using
the ‘@nodedescription’ command following the ‘@node’ line.  Such a
description might elaborate on or extend the information in the node
name itself.

   You can also use a ‘@nodedescriptionblock’ environment to provide a
node description.  This may be useful for longer descriptions.

   ‘texi2any’ uses the content you provide with these commands when
outputing menus for Info output format (and, optionally, for HTML).
‘texi2any’ uses the description after a menu entry for the node if it is
generating the menu automatically, or if no description for the menu
entry was provided in an explicit ‘@menu’ block.  (*Note Menus::).

   Here is an example of using these commands:

     @node Tools
     @chapter Tools

     This chapter is on different tools you can use.

     @node Screwdrivers
     @nodedescription Flathead and Phillips.
     @section Screwdrivers

     This section is about screwdrivers.

     @node Drills
     @nodedescriptionblock
     Making holes in things with power screwdrivers, drill drivers, combi
     drills, impact drivers, hammer drills, breakers and demolition drills.
     @end nodedescriptionblock
     @section Drills

     This section is about drills.

   In Info output, ‘texi2any’ would output the ‘Tools’ node with a menu
as follows:

     * Menu:

     * Screwdrivers::          Flathead and Phillips.
     * Drills::                Making holes in things with power
                               screwdrivers, drill drivers, combi
                               drills, impact drivers, hammer drills,
                               breakers and demolition drills.


File: texinfo.info,  Node: Menus,  Prev: Node Descriptions,  Up: Nodes

3.9 Menus
=========

“Menus” contain pointers to subordinate nodes.  In Info output, you use
menus to go to such nodes.  ‘texi2any’ can output menus in HTML output,
but does not do so by default (*note HTML Output Structure
Customization::, ‘FORMAT_MENU’).  Menus have no role in printed manuals
or other output formats.

   Menus are automatically generated by ‘texi2any’ when outputting Info
or HTML with menus for nodes followed by a sectioning command, without
an explicit ‘@menu’ block, and with automatic pointers.

   It is often more convenient to let ‘texi2any’ generate menus for you,
as you do not then have the burden of updating menu blocks in your
Texinfo source when you add, remove, or relocate nodes.  In the usual
case of a hierarchically organized manual with sectioning commands
associated with nodes, and with node pointers left out, you should only
write menus if you want exact control over the contents and formatting
of menus in Info.

* Menu:

* Writing a Menu::             What is a menu?
* Menu Example::               Two and three part menu entries.
* Menu Location::              Menus go at the ends of nodes.
* Menu Parts::                 A menu entry has three parts.
* Less Cluttered Menu Entry::  Two part menu entry.
* Other Info Files::           How to refer to a different Info file.


File: texinfo.info,  Node: Writing a Menu,  Next: Menu Example,  Up: Menus

3.9.1 Writing a Menu
--------------------

A menu consists of a ‘@menu’ command on a line by itself, followed by
menu entry lines or menu comment lines, and then followed by an ‘@end
menu’ command on a line by itself.

   A menu looks like this:

     @menu
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                      several files at once.
     @end menu

   In a menu, every line that begins with an ‘* ’ is a “menu entry”.
(Note the space after the asterisk.)

   A line that does not start with an ‘* ’ may also appear in a menu.
Such a line is not a menu entry but rather a “menu comment” line that
appears in the Info file.  In the example above, the line ‘Larger Units
of Text’ is such a menu comment line; the two lines starting with ‘* ’
are menu entries.

   Technically, menus can carry you to any node, regardless of the
structure of the document; even to nodes in a different Info file.
However, the ‘texi2any’ implicit pointer creation feature (*note Writing
a Node::) and GNU Emacs Texinfo mode updating commands work only to
create menus of subordinate nodes in a hierarchically structured
document.  In a hierarchically structured document, it is much better to
use cross-references to refer to arbitrary nodes.

   In Info, a user selects a node with the ‘m’ (‘Info-menu’) command.
The menu entry name is what the user types after the ‘m’ command.  In
the HTML output, the ‘accesskey’ attribute is used with the values
‘1’...‘9’ for the first nine entries.  This allows people using web
browsers to follow the first menu entries using (typically) ‘M-DIGIT’,
e.g., ‘M-1’ for the first entry.


File: texinfo.info,  Node: Menu Example,  Next: Menu Location,  Prev: Writing a Menu,  Up: Menus

3.9.2 A Menu Example
--------------------

A menu looks like this in Texinfo:

     @menu
     * menu entry name: Node name.   A short description.
     * Node name::                   This form is preferred.
     @end menu

This produces:

     * Menu:

     * menu entry name: Node name.   A short description.
     * Node name::                   This form is preferred.

   Here is an example as you might see it in a Texinfo file:

     @menu
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                      several files at once.
     @end menu

This produces:

     * Menu:
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                      several files at once.

   In this example, the menu has two entries.  ‘Files’ is both a menu
entry name and the name of the node referred to by that name.
‘Multiples’ is the menu entry name; it refers to the node named
‘Buffers’.  The line ‘Larger Units of Text’ is a comment; it appears in
the menu, but is not an entry.

   Since no file name is specified with either ‘Files’ or ‘Buffers’,
they must be the names of nodes in the same Info file (*note Referring
to Other Info Files: Other Info Files.).


File: texinfo.info,  Node: Menu Location,  Next: Menu Parts,  Prev: Menu Example,  Up: Menus

3.9.3 Menu Location
-------------------

There may be at most one menu in a node.  A menu is conventionally
located at the end of a node, without any regular text or additional
commands between the ‘@end menu’ and the beginning of the next node.

   This convention is useful, since a reader who uses the menu could
easily miss any such text.  Also, any such post-menu text will be
considered part of the menu in Info output (which has no marker for the
end of a menu).  Thus, a line beginning with ‘* ’ will likely be
incorrectly handled.

   It's usually best if a node with a menu does not contain much text.
If you find yourself with a lot of text before a menu, we generally
recommend moving all but a couple of paragraphs into a new subnode.
Otherwise, it is easy for readers to miss the menu.


File: texinfo.info,  Node: Menu Parts,  Next: Less Cluttered Menu Entry,  Prev: Menu Location,  Up: Menus

3.9.4 The Parts of a Menu
-------------------------

A menu entry has three parts, only the second of which is required:

  1. The menu entry name (optional).

  2. The name of the node (required).

  3. A description of the item (optional).

   The template for a generic menu entry looks like this (but see the
next section for one more possibility):

     * MENU-ENTRY-NAME: NODE-NAME.   DESCRIPTION

   Follow the menu entry name with a single colon, and follow the node
name with tab, comma, newline, or the two characters period and space
(‘. ’).

   The third part of a menu entry is a descriptive phrase or sentence.
Menu entry names and node names are often short; the description
explains to the reader what the node is about.  A useful description
complements the node name rather than repeats it.  The description,
which is optional, can spread over multiple lines; if it does, some
authors prefer to indent the second line while others prefer to align it
with the first (and all others).  It's up to you.  An empty line, or the
next menu entry, ends a description.

   Space characters in a menu are preserved as-is in the Info output;
this allows you to format the menu as you wish.  Unfortunately you must
type node names without any extra spaces or some versions of some Info
readers will not find the node (*note Node Line Requirements::).

   ‘texi2any’ warns and protect names when the text of a menu item (and
node names and cross-references) contains a problematic construct that
could interfere with its parsing in Info.  *Note Info Node Names
Constraints::.


File: texinfo.info,  Node: Less Cluttered Menu Entry,  Next: Other Info Files,  Prev: Menu Parts,  Up: Menus

3.9.5 Less Cluttered Menu Entry
-------------------------------

When the menu entry name and node name are the same, you can write the
name immediately after the asterisk and space at the beginning of the
line and follow the name with two colons.

   For example, write

     * Name::                        DESCRIPTION

instead of

     * Name: Name.                   DESCRIPTION

   We recommend using the node name for the menu entry name whenever
possible, since it reduces visual clutter in the menu.


File: texinfo.info,  Node: Other Info Files,  Prev: Less Cluttered Menu Entry,  Up: Menus

3.9.6 Referring to Other Info Files
-----------------------------------

You can create a menu entry that enables a reader in Info to go to a
node in another Info file by writing the file name in parentheses just
before the node name.  Some examples:

     @menu
     * FIRST-ENTRY-NAME:(FILENAME)NODENAME.     DESCRIPTION
     * (FILENAME)SECOND-NODE::                  DESCRIPTION
     @end menu

   For example, to refer directly to the ‘Outlining’ and ‘Rebinding’
nodes in the ‘Emacs Manual’, you could write a menu like this:

     @menu
     * Outlining: (emacs)Outline Mode. The major mode for
                                        editing outlines.
     * (emacs)Rebinding::              How to redefine the
                                        meaning of a key.
     @end menu

   If you do not list the node name, but only name the file, then Info
presumes that you are referring to the 'Top' node.  Examples:

     * Info: (info).         Documentation browsing system.
     * (emacs)::             The extensible, self-documenting
                              text editor.

   The GNU Emacs Texinfo mode menu updating commands only work with
nodes within the current buffer, so you cannot use them to create menus
that refer to other files.  You must write such menus by hand.  *Note
Updating Nodes and Menus::.


File: texinfo.info,  Node: Chapter Structuring,  Next: Cross References,  Prev: Nodes,  Up: Top

4 Chapter Structuring
*********************

Texinfo's “chapter structuring” commands divide a document into a
hierarchy of chapters, sections, subsections, and subsubsections.  These
commands generate large headings in the text, like the one above.  They
also provide information for generating the table of contents (*note
Generating a Table of Contents: Contents.).

   Normally you put a ‘@node’ command immediately before each chapter
structuring command.  *Note Nodes::.

* Menu:

* Tree Structuring::           A manual is like an upside down tree ...
* Structuring Command Types::
* @chapter::
* @unnumbered @appendix::
* @majorheading @chapheading::
* @section::
* @unnumberedsec @appendixsec @heading::
* @subsection::
* @unnumberedsubsec @appendixsubsec @subheading::
* @subsubsection::
* @part::                      Collections of chapters.
* Raise/lower sections::       How to change commands' hierarchical level.


File: texinfo.info,  Node: Tree Structuring,  Next: Structuring Command Types,  Up: Chapter Structuring

4.1 Tree Structure of Sections
==============================

A Texinfo file is usually structured like a book with chapters,
sections, subsections, and the like.  This structure can be visualized
as a tree (or rather as an upside-down tree) with the root at the top
and the levels corresponding to chapters, sections, subsection, and
subsubsections.

   Here is a diagram that shows a Texinfo file with three chapters, each
with two sections.

                              Top
                               |
             -------------------------------------
            |                  |                  |
         Chapter 1          Chapter 2          Chapter 3
            |                  |                  |
         --------           --------           --------
        |        |         |        |         |        |
     Section  Section   Section  Section   Section  Section
       1.1      1.2       2.1      2.2       3.1      3.2

   In a Texinfo file that has this structure, the beginning of Chapter 2
would be written like this:

     @node    Chapter 2
     @chapter Chapter 2

For purposes of example, here is how it would be written with explicit
node pointers:

     @node    Chapter 2,  Chapter 3, Chapter 1, Top
     @chapter Chapter 2

   The chapter structuring commands are described in the sections that
follow; the ‘@node’ command is described in the previous chapter (*note
Nodes::).


File: texinfo.info,  Node: Structuring Command Types,  Next: @chapter,  Prev: Tree Structuring,  Up: Chapter Structuring

4.2 Structuring Command Types
=============================

The chapter structuring commands fall into four groups, each of which
contains structuring commands at the levels of chapters, sections,
subsections, and subsubsections:

   • The ‘@chapter’-like commands and ‘@appendix’-like commands produce
     numbered or lettered entries both in the body of a document and in
     its table of contents.

   • The ‘@unnumbered’-like commands produce unnumbered entries both in
     the body of a document and in its table of contents.  The ‘@top’
     command, which has a special use, is a member of this group (*note
     @top Command::).  An ‘@unnumbered’ section is a normal part of the
     document structure.

   • The ‘@heading’-like commands produce simple unnumbered headings
     that do not appear in a table of contents, are not associated with
     nodes, and cannot be cross-referenced.  These heading commands
     never start a new page.

   In printed output, the chapter structuring commands produce headings
in the document.  When a ‘@setchapternewpage’ command says to do so, the
‘@chapter’, ‘@unnumbered’, and ‘@appendix’ commands start new pages in
the printed manual; the ‘@heading’ commands do not.  *Note
@setchapternewpage::.

   In Info and plain text output, the command causes the title to appear
on a line by itself, with a line of an ASCII character (‘*’, ‘=’, ...)
inserted underneath.  For example, the "Chapter Structuring" heading
could be:

     5 Chapter Structuring
     *********************

The underlining character is the same for all the commands at the same
level.  For instance, it is the same for the chapter-level commands
‘@chapter’, ‘@apppendix’, ‘@unnumbered’ and ‘@chapheading’.

   In HTML, the chapter-level commands produce an ‘<h2>’-level header by
default (controlled by the ‘CHAPTER_HEADER_LEVEL’ customization
variable, *note HTML Customization of Specific Output::).  The heading
element level is adjusted for the other commands.

   In the DocBook output, the appropriate level of element is used.  The
produced element includes all following sections up to the next command
at the same or higher level.  For example, a ‘<chapter>’ element is
produced for ‘@chapter’, and contains any sections or subsections in the
chapter.

   Here is a summary:

                                                            No new page
Numbered       Unnumbered             Lettered/numbered     Unnumbered
In contents    In contents            In contents           Not in
                                                            contents
               ‘@top’                                       ‘@majorheading’
‘@chapter’     ‘@unnumbered’          ‘@appendix’           ‘@chapheading’
‘@section’     ‘@unnumberedsec’       ‘@appendixsec’        ‘@heading’
‘@subsection’  ‘@unnumberedsubsec’    ‘@appendixsubsec’     ‘@subheading’
‘@subsubsection’‘@unnumberedsubsubsec’‘@appendixsubsubsec’  ‘@subsubheading’


File: texinfo.info,  Node: @chapter,  Next: @unnumbered @appendix,  Prev: Structuring Command Types,  Up: Chapter Structuring

4.3 ‘@chapter’: Chapter Structuring
===================================

‘@chapter’ identifies a chapter in the document-the highest level of the
normal document structuring hierarchy.  Write the command at the
beginning of a line and follow it on the same line by the title of the
chapter.  The chapter is numbered automatically, starting from 1.

   For example, the present chapter in this manual is entitled "Chapter
Structuring"; the ‘@chapter’ line looks like this:

     @chapter Chapter Structuring


File: texinfo.info,  Node: @unnumbered @appendix,  Next: @majorheading @chapheading,  Prev: @chapter,  Up: Chapter Structuring

4.4 ‘@unnumbered’, ‘@appendix’: Chapters with Other Labeling
============================================================

Use the ‘@unnumbered’ command to start a chapter-level element that
appears without chapter numbers of any kind.  Use the ‘@appendix’
command to start an appendix that is labeled by letter ('A', 'B', ...)
instead of by number; appendices are also at the chapter level of
structuring.

   Write an ‘@appendix’ or ‘@unnumbered’ command at the beginning of a
line and follow it on the same line by the title, just as with
‘@chapter’.

   Texinfo also provides a command ‘@centerchap’, which is analogous to
‘@unnumbered’, but centers its argument in the printed and HTML outputs.
This kind of stylistic choice is not usually offered by Texinfo.  You
are recommended not to use this command, as it may be removed in future
releases of Texinfo.

   With ‘@unnumbered’, if the name of the associated node is one of
these English words (case-insensitive):

     Acknowledgements  Colophon  Dedication  Preface

then the DocBook output uses corresponding special tags (‘<preface>’,
etc.) instead of the default ‘<chapter>’.  The argument to ‘@unnumbered’
itself can be anything, and is output as the element title as usual.


File: texinfo.info,  Node: @majorheading @chapheading,  Next: @section,  Prev: @unnumbered @appendix,  Up: Chapter Structuring

4.5 ‘@majorheading’, ‘@chapheading’: Chapter-level Headings
===========================================================

The ‘@majorheading’ and ‘@chapheading’ commands produce chapter-like
headings in the body of a document.

   However, neither command produces an entry in the table of contents,
and neither command causes TeX to start a new page in a printed manual.

   In TeX, a ‘@majorheading’ command generates a larger vertical
whitespace before the heading than a ‘@chapheading’ command but is
otherwise the same.

   In other output formats, the ‘@majorheading’ and ‘@chapheading’
commands produce a similar output to ‘@chapter’.  The difference is the
lack of numbering and the lack of any association with nodes.  *Note
@chapter::.


File: texinfo.info,  Node: @section,  Next: @unnumberedsec @appendixsec @heading,  Prev: @majorheading @chapheading,  Up: Chapter Structuring

4.6 ‘@section’: Sections Below Chapters
=======================================

An ‘@section’ command identifies a section within a chapter unit,
whether created with ‘@chapter’, ‘@unnumbered’, or ‘@appendix’,
following the numbering scheme of the chapter-level command.  Thus,
within a ‘@chapter’ chapter numbered '1', the sections are numbered
'1.1', '1.2', etc.; within an ‘@appendix’ "chapter" labeled 'A', the
sections are numbered 'A.1', 'A.2', etc.; within an ‘@unnumbered’
chapter, the section gets no number.

   To make a section, write the ‘@section’ command at the beginning of a
line and follow it on the same line by the section title.  For example:

     @section This is a section

   Section titles are listed in the table of contents.


File: texinfo.info,  Node: @unnumberedsec @appendixsec @heading,  Next: @subsection,  Prev: @section,  Up: Chapter Structuring

4.7 ‘@unnumberedsec’, ‘@appendixsec’, ‘@heading’
================================================

The ‘@unnumberedsec’, ‘@appendixsec’, and ‘@heading’ commands are,
respectively, the unnumbered, appendix-like, and heading-like
equivalents of the ‘@section’ command (see the previous section).

   ‘@unnumberedsec’ and ‘@appendixsec’ do not need to be used in
ordinary circumstances, because ‘@section’ may also be used within
‘@unnumbered’ and ‘@appendix’ chapters; again, see the previous section.

‘@unnumberedsec’
     The ‘@unnumberedsec’ command may be used within an unnumbered
     chapter or within a regular chapter or appendix to produce an
     unnumbered section.

‘@appendixsec’
‘@appendixsection’
     ‘@appendixsection’ is a longer spelling of the ‘@appendixsec’
     command; the two are synonymous.

     Conventionally, the ‘@appendixsec’ or ‘@appendixsection’ command is
     used only within appendices.

‘@heading’
     You may use the ‘@heading’ command (almost) anywhere for a
     section-style heading that will not appear in the table of
     contents.  The ‘@heading’-series commands can appear inside most
     environments, for example, though pathological and useless
     locations such as an argument to another command, etc., are not
     allowed.


File: texinfo.info,  Node: @subsection,  Next: @unnumberedsubsec @appendixsubsec @subheading,  Prev: @unnumberedsec @appendixsec @heading,  Up: Chapter Structuring

4.8 ‘@subsection’: Subsections Below Sections
=============================================

Subsections are to sections as sections are to chapters; *note
@section::.  For example:

     @subsection This is a subsection

   Subsection titles are listed in the table of contents.


File: texinfo.info,  Node: @unnumberedsubsec @appendixsubsec @subheading,  Next: @subsubsection,  Prev: @subsection,  Up: Chapter Structuring

4.9 The ‘@subsection’-like Commands
===================================

The ‘@unnumberedsubsec’, ‘@appendixsubsec’, and ‘@subheading’ commands
are, respectively, the unnumbered, appendix-like, and heading-like
equivalents of the ‘@subsection’ command.  (*Note @subsection::.)

   ‘@unnumberedsubsec’ and ‘@appendixsubsec’ do not need to be used in
ordinary circumstances, because ‘@subsection’ may also be used within
sections of ‘@unnumbered’ and ‘@appendix’ chapters (*note @section::).

   An ‘@subheading’ command produces a heading like that of a subsection
except that it is not numbered and does not appear in the table of
contents.  Similarly, an ‘@unnumberedsubsec’ command produces an
unnumbered heading like that of a subsection and an ‘@appendixsubsec’
command produces a subsection-like heading labeled with a letter and
numbers; both of these commands produce headings that appear in the
table of contents.


File: texinfo.info,  Node: @subsubsection,  Next: @part,  Prev: @unnumberedsubsec @appendixsubsec @subheading,  Up: Chapter Structuring

4.10 ‘@subsubsection’ and Other Subsub Commands
===============================================

The fourth and lowest level sectioning commands in Texinfo are the
'subsub' commands.  They are:

‘@subsubsection’
     Subsubsections are to subsections as subsections are to sections.
     (*Note @subsection::.)  Subsubsection titles appear in the table of
     contents.

‘@unnumberedsubsubsec’
     Unnumbered subsubsection titles appear in the table of contents,
     but lack numbers.  Otherwise, unnumbered subsubsections are the
     same as subsubsections.

‘@appendixsubsubsec’
     Conventionally, appendix commands are used only for appendices and
     are lettered and numbered appropriately.  They also appear in the
     table of contents.

‘@subsubheading’
     The ‘@subsubheading’ command may be used anywhere that you want a
     small heading that will not appear in the table of contents.

   As with subsections, ‘@unnumberedsubsubsec’ and ‘@appendixsubsubsec’
do not need to be used in ordinary circumstances, because
‘@subsubsection’ may also be used within subsections of ‘@unnumbered’
and ‘@appendix’ chapters (*note @section::).


File: texinfo.info,  Node: @part,  Next: Raise/lower sections,  Prev: @subsubsection,  Up: Chapter Structuring

4.11 ‘@part’: Groups of Chapters
================================

The final sectioning command is ‘@part’, to mark a “part” of a manual,
that is, a group of chapters or (rarely) appendices.  This behaves quite
differently from the other sectioning commands, to fit with the way such
"parts" are conventionally used in books.

   No ‘@node’ command is associated with ‘@part’.  Just write the
command on a line by itself, including the part title, at the place in
the document you want to mark off as starting that part.  For example:

     @part Part I:@* The beginning

   As can be inferred from this example, no automatic numbering or
labeling of the ‘@part’ text is done.  The text is taken as-is.

   Because parts are not associated with nodes, no general text can
follow the ‘@part’ line.  To produce the intended output, it must be
followed by a chapter-level command (including its node).  Thus, to
continue the example:

     @part Part I:@* The beginning

     @node Introduction
     @chapter Introduction
     ...

   In the TeX output, the ‘@part’ text is included in both the normal
and short tables of contents (*note Contents::), without a page number
(since that is the normal convention).  In addition, a "part page" is
output in the body of the document, with just the ‘@part’ text.  In the
example above, the ‘@*’ causes a line break on the part page (but is
replaced with a space in the tables of contents).  This part page is
always forced to be on an odd (right-hand) page, regardless of the
chapter pagination (*note @setchapternewpage::).  In the LaTeX output,
the ‘@part’ is output as ‘\part’.

   In the HTML output, the ‘@part’ text is similarly included in the
tables of contents, and a heading is included in the main document text,
as part of the following chapter or appendix node.

   In the DocBook output, the ‘<part>’ element includes all the
following chapters, up to the next ‘<part>’.  A ‘<part>’ containing
chapters is also closed at an appendix.

   In the Info and plain text output, ‘@part’ has no effect.

   ‘@part’ is ignored when raising or lowering sections (see next
section).  That is, it is never lowered and nothing can be raised to it.


File: texinfo.info,  Node: Raise/lower sections,  Prev: @part,  Up: Chapter Structuring

4.12 Raise/lower Sections: ‘@raisesections’ and ‘@lowersections’
================================================================

The ‘@raisesections’ and ‘@lowersections’ commands implicitly raise and
lower the hierarchical level of following chapters, sections and the
other sectioning commands (excluding parts).

   That is, the ‘@raisesections’ command changes sections to chapters,
subsections to sections, and so on.  Conversely, the ‘@lowersections’
command changes chapters to sections, sections to subsections, and so
on.  Thus, a ‘@lowersections’ command cancels a ‘@raisesections’
command, and vice versa.

   As a practical matter, you generally only want to raise or lower
large chunks, usually in external files.  You can use ‘@lowersections’
to include text written as an outer or standalone Texinfo file in
another Texinfo file as an inner, included file (*note Include Files::).
Typical usage looks like this:

     @lowersections
     @include somefile.texi
     @raisesections

(Without the ‘@raisesections’, all the subsequent sections in the main
file would also be lowered.)

   If the included file being lowered has a ‘@top’ node, you'll need to
conditionalize its inclusion with a flag (*note @set @value::).

   Any menus in the final result have to take the raising and lowering
into account, so arbitrarily sprinkling ‘@raisesections’ and
‘@lowersections’ commands throughout the document will likely lead to
errors (unless the menus in your document are all generated
automatically).

   Repeated use of the commands continues to raise or lower the
hierarchical level a step at a time.  An attempt to raise above
'chapter' reproduces chapter commands; an attempt to lower below
'subsubsection' reproduces subsubsection commands.  Also, lowered
subsubsections and raised chapters will not work with ‘texi2any’'s
feature of implicitly determining node pointers, since the menu
structure cannot be represented correctly.

   Write each ‘@raisesections’ and ‘@lowersections’ command on a line of
its own.


File: texinfo.info,  Node: Cross References,  Next: Marking Text,  Prev: Chapter Structuring,  Up: Top

5 Cross-references
******************

“Cross-references” are used to refer the reader to other parts of the
same or different Texinfo files.

   Use cross-references to provide access to information that is too
detailed for the current context, or incidental to it.  An online help
system or a reference manual is not like a novel; few read such
documents in sequence from beginning to end.  Instead, people look up
what they need.  For this reason, such creations should contain many
cross-references to help readers find other information that they may
not have read.

   In a printed manual, a cross-reference results in a page reference,
unless it is to another manual altogether, in which case the
cross-reference names that manual.  In Info, a cross-reference results
in an entry that you can follow using the Info ‘f’ command.  (*Note
Following cross-references: (info)Help-Xref.)  In HTML, a
cross-reference results in an hyperlink.  In DocBook, the ‘<link>’
element is used for cross-references unless it is to another manual, in
which case the cross-reference names that manual.

   The various cross-reference commands use nodes, anchors (*note
@anchor::) or float labels (*note @float::) to define cross-reference
locations.  When TeX generates a DVI file, it records each
cross-reference location page number and uses the page numbers in making
references.  Thus, even if you are writing a manual that will only be
printed, and not used online, you must nonetheless write ‘@node’ lines
(or ‘@anchor’ anchors) in order to name the places to which you make
cross-references.

* Menu:

* Cross Reference Commands::   A summary of the different commands.
* Cross Reference Parts::      A cross-reference has several parts.
* One Argument::               ‘@xref’ with one argument.
* Two Arguments::              ‘@xref’ with two arguments.
* Three Arguments::            ‘@xref’ with three arguments.
* Four and Five Arguments::    ‘@xref’ with four and five arguments.
* Referring to a Manual as a Whole::  Refer to an entire manual.
* @xref::                      Begin a reference with 'See' ...
* @ref::                       A reference for the last part of a sentence.
* @pxref::                     How to write a parenthetical cross-reference.
* @anchor::                    Defining arbitrary cross-reference targets
* @link::                      How to make a plain link.
* @inforef::                   How to refer to an Info-only file.
* @url::                       How to refer to a uniform resource locator.
* @cite::                      How to refer to books not in the Info system.
* PDF Colors::                 Colorizing URLs and other links in PDF output.


File: texinfo.info,  Node: Cross Reference Commands,  Next: Cross Reference Parts,  Up: Cross References

5.1 Different Cross-reference Commands
======================================

There are three different cross-reference commands:

‘@xref’
     Used to start a sentence with an Info cross-reference saying ‘*Note
     NAME: NODE.’ or with 'See ...' in other output formats.

‘@ref’
     Used within or, more often, at the end of a sentence; produces an
     Info cross-reference saying ‘*note NAME: NODE.’, and just the
     reference in other output formats, without the preceding 'See'.

‘@pxref’
     Used within parentheses, at the end of a sentence, or otherwise
     before punctuation, to make a reference.  Its output starts with a
     lowercase ‘*note’ in Info, and with a lowercase 'see' in the other
     output formats.  (‘p’ is for 'parenthesis'.)

   Additionally, there are commands to produce references to documents
outside the Texinfo system.  The ‘@cite’ command is used to make
references to books and manuals.  ‘@url’ produces a URL, for example a
reference to a page on the World Wide Web.


File: texinfo.info,  Node: Cross Reference Parts,  Next: One Argument,  Prev: Cross Reference Commands,  Up: Cross References

5.2 Parts of a Cross-reference
==============================

A cross-reference command requires only one argument, which is the name
of the node to which it refers.  A cross-reference command may contain
up to four additional arguments.  The template for a full five argument
cross-reference looks like this:

     @xref{NODE-NAME, ONLINE-LABEL, PRINTED-LABEL,
     MANUAL-NAME, PRINTED-MANUAL-TITLE}

   The five possible arguments for a cross-reference are:

  1. The node or anchor name.  This is the location to which the
     cross-reference takes you.  In a printed document, the location of
     the node provides the page reference only for references within the
     same document.  Use ‘@node’ to define the node (*note Writing a
     Node::), ‘@anchor’ (*note @anchor::), or ‘@float’ (*note @float::)
     with a label.  This argument is required (except for reference to
     whole manuals).

     Write a node name in a cross-reference in exactly the same way as
     in the ‘@node’ line, including the same capitalization; otherwise,
     the processors may not find the reference.

  2. A label for online output.  It is usually omitted; then the topic
     description (third argument) is used if it was specified; if that
     was omitted as well, the node name is used.

  3. A label for printed output.  Often, this is the title or topic of
     the section.  This is used as the name of the reference in the
     printed manual.  If omitted, the node name is used.

  4. The name of the manual to which the reference refers, if it is
     outside the current manual, in a different Texinfo file.

  5. The title of the printed manual to which the reference refers, from
     a different Texinfo file.

   Whitespace before and after the commas separating these arguments is
ignored.  To include a comma in one of the arguments, use ‘@comma{}’
(*note Inserting a Comma::).

   Cross-references with one, two, three, four, and five arguments are
described separately in following sections.

   When processing with TeX, a comma is automatically inserted after the
page number for cross-references to within the same manual, unless the
closing brace of the argument is followed by non-whitespace (such as a
comma or period).  This gives you the choice of whether to have a comma
there in other output formats.  For example,

     @xref{Another Section} for more info

with TeX produces 'See Another Section, page PPP, for more info', and in
the Info output produces ‘*Note Another Section:: for more info’.

   If an unwanted comma is added, follow the argument with a command
such as ‘@:’.  For example, ‘@xref{Hurricanes}@: --- for the details’
produces

     See Hurricanes, page PPP -- for the details

instead of 'See Hurricanes, page PPP, -- for the details'.

   ‘texi2any’ warns and protect names when the text of a cross-reference
(and node names and menu items) contains a problematic construct that
could interfere with its parsing in Info.  *Note Info Node Names
Constraints::.


File: texinfo.info,  Node: One Argument,  Next: Two Arguments,  Prev: Cross Reference Parts,  Up: Cross References

5.3 ‘@xref’ with One Argument
=============================

The simplest form of ‘@xref’ takes one argument, the name of another
node in the same Texinfo file.

For example,

     @xref{Tropical Storms}.

produces

     *Note Tropical Storms::.

in Info and

     See Section 3.1 [Tropical Storms], page 24.

in a printed manual.


File: texinfo.info,  Node: Two Arguments,  Next: Three Arguments,  Prev: One Argument,  Up: Cross References

5.4 ‘@xref’ with Two Arguments
==============================

With two arguments, the second is used as a label for the online output.

The template is like this:

     @xref{NODE-NAME, ONLINE-LABEL}.

For example,

     @xref{Electrical Effects, Lightning}.

produces:

     *Note Lightning: Electrical Effects.

in Info and

     See Section 5.2 [Electrical Effects], page 57.

in a printed manual, where the node name is printed.

   The second argument to cross-references shares constraints with node
names.  The potentially problematic character in this context is the
colon.  *Note Info Node Names Constraints::.


File: texinfo.info,  Node: Three Arguments,  Next: Four and Five Arguments,  Prev: Two Arguments,  Up: Cross References

5.5 ‘@xref’ with Three Arguments
================================

A third argument replaces the node name in the printed output.  The
third argument should be the name of the section in the printed output,
or else state the topic discussed by that section.

The template is like this:

     @xref{NODE-NAME, ONLINE-LABEL, PRINTED-LABEL}.

For example,

     @xref{Electrical Effects, Lightning, Thunder and Lightning},
     for details.

produces

     *Note Lightning: Electrical Effects, for details.

in Info and

     See Section 5.2 [Thunder and Lightning], page 57, for details.

in a printed manual.

   If a third argument is given and the second one is empty, then the
third argument serves for both.  (Note how two commas, side by side,
mark the empty second argument.)

     @xref{Electrical Effects, , Thunder and Lightning},
     for details.

produces

     *Note Thunder and Lightning: Electrical Effects, for details.

in Info and

     See Section 5.2 [Thunder and Lightning], page 57, for details.

in a printed manual.

   The third argument to cross-references shares constraints with node
names.  The potentially problematic character in this context is the
colon.  *Note Info Node Names Constraints::.

   As a practical matter, it is often best to write cross-references
with just the first argument if the node name and the section title are
the same (or nearly so), and with the first and third arguments only if
the node name and title are different.

   Texinfo offers a setting to use the section title instead of node
names by default in cross-references (an explicitly specified third
argument still takes precedence):

     @xrefautomaticsectiontitle on

   Typically this line would be given near the beginning of the document
and used for the whole manual.  But you can turn it off if you want
(‘@xrefautomaticsectiontitle off’), for example, if you're including
some other sub-document that doesn't have suitable section names.  This
setting also applies to node headers in HTML, if
‘@xrefautomaticsectiontitle’ is on, the sections names are used in node
headers instead of the node names when possible.


File: texinfo.info,  Node: Four and Five Arguments,  Next: Referring to a Manual as a Whole,  Prev: Three Arguments,  Up: Cross References

5.6 ‘@xref’ with Four and Five Arguments
========================================

In a cross-reference, a fourth argument specifies the name of another
manual, different from the file in which the reference appears, and a
fifth argument specifies its title as a printed manual.

The full template is:

     @xref{NODE-NAME, ONLINE-LABEL, PRINTED-LABEL,
     MANUAL-NAME, PRINTED-MANUAL-TITLE}.

For example,

     @xref{Electrical Effects, Lightning, Thunder and Lightning,
     weather, An Introduction to Meteorology}.

produces this output in Info:

     *Note Lightning: (weather)Electrical Effects.

As you can see, the name of the manual is enclosed in parentheses and
precedes the name of the node.  In HTML, the manual name and the node
name are used to construct the hyperlink URL (*note HTML Xref::), while
the link text is based on the label.

In a printed manual, the reference looks like this:

     See section "Thunder and Lightning" in ‘An Introduction to
     Meteorology’.

The title of the printed manual is typeset like ‘@cite’; and the
reference lacks a page number since the page a reference refers when
that reference is to another manual cannot be known.

   Next case: often, you will leave out the second argument when you use
the long version of ‘@xref’.  In this case, the third argument, the
topic description, will be used as the cross-reference name in online
formats.  For example,

     @xref{Electrical Effects, , Thunder and Lightning,
     weather, An Introduction to Meteorology}.

produces

     *Note Thunder and Lightning: (weather)Electrical Effects.

in Info and

     See section "Thunder and Lightning" in ‘An Introduction to
     Meteorology’.

in a printed manual.

   Next case: If the node name and the section title are the same in the
other manual, you may also leave out the section title.  In this case,
the node name is used in both instances.  For example,

     @xref{Electrical Effects,,,
     weather, An Introduction to Meteorology}.

produces

     *Note (weather)Electrical Effects::.

in Info and

     See section "Electrical Effects" in ‘An Introduction to
     Meteorology’.

in a printed manual.

   In general, there is no reason to have a manual name argument without
a printed manual argument, unless no printed manual is generated.  You
may also want to refer to another manual file that is within a single
printed manual--when multiple Texinfo files are incorporated into the
same printed manual but can create separate output files in other output
formats.  In this case, you need to specify only the fourth argument,
and not the fifth.  If the printed manual title argument is missing, the
manual name will be used instead in printed output.

   A printed manual title argument without an online manual argument is
of little use unless only a printed manual is generated from the Texinfo
source.  The result in online formats depends on the format, and can be,
for example, an empty manual name or a reference to the printed manual
formatted in a similar way to the printed output.

   Finally, it's also allowed to leave out all the arguments _except_
the fourth and fifth, to refer to another manual as a whole.  See the
next section.


File: texinfo.info,  Node: Referring to a Manual as a Whole,  Next: @xref,  Prev: Four and Five Arguments,  Up: Cross References

5.7 Referring to a Manual as a Whole
====================================

Ordinarily, you must always name a node in a cross-reference.  However,
it's not unusual to want to refer to another manual as a whole, rather
than a particular section within it.  In this case, giving any section
name is an unnecessary distraction.

   So, with cross-references to other manuals (*note Four and Five
Arguments::), if the first argument is either ‘Top’ (capitalized just
that way) or omitted entirely, and the third argument is omitted, the
printed output includes no node or section name.  (The Info output
includes ‘Top’ if it was given.)  For example,

     @xref{Top,,, make, The GNU Make Manual}.

produces

     *Note (make)Top::.

and

     See ‘The GNU Make Manual’.

Info readers will go to the Top node of the manual whether or not the
'Top' node is explicitly specified.

   It's also possible (and is historical practice) to refer to a whole
manual by specifying the 'Top' node and an appropriate entry for the
third argument to the ‘@xref’ command.  Using this idiom, to make a
cross-reference to ‘The GNU Make Manual’, you would write:

     @xref{Top,, Overview, make, The GNU Make Manual}.

which produces

     *Note Overview: (make)Top.

in Info and

     See section "Overview" in ‘The GNU Make Manual’.

in a printed manual.

   In this example, ‘Top’ is the name of the first node, and ‘Overview’
is the name of the first section of the manual.  There is no widely-used
convention for naming the first section in a printed manual, this is
just what the Make manual happens to use.  This arbitrariness of the
first name is a principal reason why omitting the third argument in
whole-manual cross-references is preferable.


File: texinfo.info,  Node: @xref,  Next: @ref,  Prev: Referring to a Manual as a Whole,  Up: Cross References

5.8 ‘@xref’
===========

The ‘@xref’ command generates a cross-reference for the beginning of a
sentence.  Examples of using ‘@xref’ are in previous sections.


File: texinfo.info,  Node: @ref,  Next: @pxref,  Prev: @xref,  Up: Cross References

5.9 ‘@ref’
==========

‘@ref’ is nearly the same as ‘@xref’ except that it does not generate a
'See' in the output, just the reference itself.  This makes it useful as
the last part of a sentence.

For example,

     For more information, @pxref{This}, and @ref{That}.

produces in Info:

     For more information, *note This::, and *note That::.

and in printed output:

     For more information, see Section 1.1 [This], page 1, and Section
     1.2 [That], page 2.

   The ‘@ref’ command can tempt writers to express themselves in a
manner that is suitable for a printed manual but looks awkward in the
Info format.  Bear in mind that your audience could be using both the
printed and other output formats such as Info.  For example:

     Sea surges are described in @ref{Hurricanes}.

looks ok in the printed output:

     Sea surges are described in Section 6.7 [Hurricanes], page 72.

but is awkward to read in Info, "note" being a verb:

     Sea surges are described in *note Hurricanes::.


File: texinfo.info,  Node: @pxref,  Next: @anchor,  Prev: @ref,  Up: Cross References

5.10 ‘@pxref’
=============

The parenthetical reference command, ‘@pxref’, is nearly the same as
‘@xref’, but it is best used within parentheses.  The command differs
from ‘@xref’ in that the reference is typeset with a lowercase 'see'
rather than an uppercase 'See'.  In Info, ‘*note’ is output.

With one argument, a parenthetical cross-reference looks like this:

     ... storms cause flooding (@pxref{Hurricanes}) ...

which produces

     ... storms cause flooding (*note Hurricanes::) ...

in Info and

     ... storms cause flooding (see Section 6.7 [Hurricanes], page 72)
     ...

in a printed manual.

   In past versions of Texinfo, it was not allowed to write punctuation
after a ‘@pxref’, so it could be used _only_ before a right parenthesis.
This is no longer the case.  The effect of ‘@pxref{NODE-NAME}’ is
similar to that of ‘see @ref{NODE-NAME}’.  However, in many
circumstances the latter is preferable, as this makes it clear in the
Info output that the word "see" should be present.


File: texinfo.info,  Node: @anchor,  Next: @link,  Prev: @pxref,  Up: Cross References

5.11 ‘@anchor’: Defining Arbitrary Cross-reference Targets
==========================================================

An “anchor” is a position in your document, labelled so that
cross-references can refer to it, just as they can to nodes.  You create
an anchor with the ‘@anchor’ command, and give the label as a normal
brace-delimited argument.  For example:

     This marks the @anchor{x-spot}spot.
     ...
     @xref{x-spot,,the spot}.

produces:

     This marks the spot.
     ...
     See [the spot], page 1.

   As you can see, the ‘@anchor’ command itself produces no output.
This example defines an anchor 'x-spot' just before the word 'spot'.
You can refer to it later with an ‘@xref’ or other cross reference
command, as shown (*note Cross References::).

   It is best to put ‘@anchor’ commands just before the position you
wish to refer to; that way, the reader's eye is led on to the correct
text when they jump to the anchor.  You can put the ‘@anchor’ command on
a line by itself if that helps readability of the source.  Whitespace
(including newlines) is ignored after ‘@anchor’.

   Anchor names, node names and float labels may not conflict.  Anchors,
nodes and float labels are given similar treatment in some ways; for
example, the ‘goto-node’ command takes either an anchor name or a node
name as an argument.  (*Note (info)Go to node::.).  Anchors names and
float labels could also appear in menus (*note Menus::) and node
direction pointers (*note Writing a Node::), although this is not
recommended.

   Anchor names share the same constraints as nodes on the characters
that can be included (*note Info Node Names Constraints::).

   Because of this duality, when you delete or rename a node, it is
usually a good idea to define an ‘@anchor’ with the old name.  That way,
any links to the old node, whether from other Texinfo manuals or general
web pages, keep working.


File: texinfo.info,  Node: @link,  Next: @inforef,  Prev: @anchor,  Up: Cross References

5.12 ‘@link’: Plain, unadorned hyperlink
========================================

‘@link’ produces a plain hyperlink in output formats that support it,
including in HTML, DocBook, LaTeX and online PDF.  The template is:

     @link{NODE-NAME, LABEL, MANUAL-NAME}

   NODE-NAME is the name of the target node or anchor.  Either or both
of LABEL and MANUAL-NAME can be omitted.  LABEL, if given, is the text
to use for the link.  MANUAL-NAME is the name of the external manual
that the target appears within; if not given, the reference is to the
current manual.

   ‘@link’ has similar output to ‘@ref’, except that it does not produce
any extra text around the link label in Info or printed output that
would mark it as a cross-reference.

   Be careful about using ‘@link’ to produce links that are necessary
for a user to move around a manual, as these links will do nothing in
some output formats.  ‘@link’ is best used to add convenience links that
are nonetheless not essential for a reader to understand the text of the
manual.  For example, you might use ‘@link’ in a code sample to
reference documentation of a symbol in a programming library.


File: texinfo.info,  Node: @inforef,  Next: @url,  Prev: @link,  Up: Cross References

5.13 ‘@inforef’: Cross-references to Info-only Material
=======================================================

‘@inforef’ is used for making cross-references to Info documents--even
from a printed manual.  This was originally used for Info files that
were not generated from any Texinfo source.  The command is now obsolete
and should not be used.  In addition to having little use, similar
output can be obtained with ‘@xref’, ‘@ref’ or ‘@pxref’ with the Info
file name as the fourth argument and no fifth argument.

   The command takes either two or three arguments, in the following
order:

  1. The node name.

  2. The cross-reference name (optional).

  3. The Info file name.

The template is:

     @inforef{NODE-NAME, CROSS-REFERENCE-NAME, INFO-FILE-NAME}


File: texinfo.info,  Node: @url,  Next: @cite,  Prev: @inforef,  Up: Cross References

5.14 ‘@url’, ‘@uref{URL[, TEXT][, REPLACEMENT]}’
================================================

‘@url’ produces a reference to a uniform resource locator (URL). It
takes one mandatory argument, the URL, and two optional arguments which
control the text that is displayed.  In HTML and PDF output, ‘@url’
produces a link you can follow.  (To merely indicate a URL without
creating a link people can follow, use ‘@indicateurl’, *note
@indicateurl::.)

   ‘@uref’ is a synonym for ‘@url’.  (Originally, ‘@url’ had the meaning
of ‘@indicateurl’ and ‘@uref’ was required to produce a working link,
but in practice ‘@url’ was almost always misused.  So we've changed the
meaning.)

   The second argument, if specified, is the text to display (the
default is the URL itself); in output formats other than HTML, the URL
is output in addition to this text.

   The third argument, if specified, is the text to display, but in this
case the URL is not output in any format.  This is useful when the text
is already sufficiently referential, as in a man page.  Also, if the
third argument is given, the second argument is ignored.

* Menu:

* @url Examples::              Examples of using all the forms of ‘@url’.
* URL Line Breaking::          How lines are broken within ‘@url’ text.
* @url PDF Output Format::     A special option to hide links in PDF output.


File: texinfo.info,  Node: @url Examples,  Next: URL Line Breaking,  Up: @url

5.14.1 ‘@url’ Examples
----------------------

First, here is an example of the simplest form of ‘@url’, with just one
argument.  The given URL is both the target and the visible text of the
link:

     The official GNU ftp site is @url{http://ftp.gnu.org/gnu}.

produces:
     The official GNU ftp site is <http://ftp.gnu.org/gnu>.

Two-argument form of ‘@url’
...........................

Here is an example of the two-argument form:
     The official @url{http://ftp.gnu.org/gnu, GNU ftp site}
     holds programs and texts.

which produces:
     The official GNU ftp site (http://ftp.gnu.org/gnu)
     holds programs and texts.

The HTML output is this:
     The official <a href="http://ftp.gnu.org/gnu">GNU ftp site</a>
     holds programs and texts.

In other formats, the output is like this:
     The official GNU ftp site (http://ftp.gnu.org/gnu)
     holds programs and texts.

Three-argument form of ‘@url’
.............................

Finally, an example of the three-argument form:
     The @url{/man.cgi/1/ls,,ls} program ...

which, except for HTML, produces:
     The ls program ...

but with HTML:
     The <a href="/man.cgi/1/ls">ls</a> program ...

   By the way, some people prefer to display URLs in the unambiguous
format:

     <URL:http://HOST/PATH>

You can use this form in the input file if you wish.  We feel it's not
necessary to include the ‘<URL:’ and ‘>’ in the output, since to be
useful any software that tries to detect URLs in text already has to
detect them without the ‘<URL:’.


File: texinfo.info,  Node: URL Line Breaking,  Next: @url PDF Output Format,  Prev: @url Examples,  Up: @url

5.14.2 URL Line Breaking
------------------------

TeX allows line breaking within URLs at only a few characters (which are
special in URLs): ‘&’, ‘.’, ‘#’, ‘?’, and ‘/’ (but not between two ‘/’
characters).  A tiny amount of stretchable space is also inserted around
these characters to help with line breaking.

   For HTML output, modern browsers will also do line breaking within
displayed URLs.  If you need to allow breaks at other characters you can
insert ‘@/’ as needed (*note Line Breaks::).

   By default, in TeX any such breaks at special characters will occur
after the character.  Some people prefer such breaks to happen before
the special character.  This can be controlled with the
‘@urefbreakstyle’ command (this command has effect only in TeX):

     @urefbreakstyle HOW

where the argument HOW is one of these words:

‘after’
     (the default) Potentially break after the special characters.
‘before’
     Potentially break before the special characters.
‘none’
     Do not consider breaking at the special characters at all; any
     potential breaks must be manually inserted.


File: texinfo.info,  Node: @url PDF Output Format,  Prev: URL Line Breaking,  Up: @url

5.14.3 ‘@url’ PDF Output Format
-------------------------------

If the ultimate purpose of a PDF is only to be viewed online, perhaps
similar to HTML in some inchoate way, you may not want the URLs to be
included in the visible text (just as URLs are not visible to readers of
web pages).  Texinfo provides a PDF-specific option for this, which must
be used inside ‘@tex’:

     @tex
     \global\urefurlonlylinktrue
     @end tex

   The result is that ‘@url{http://www.gnu.org, GNU}’ has the visible
output of just 'GNU', with a link target of <http://www.gnu.org>.
Ordinarily, the visible output would include both the label and the url:
'GNU (<http://www.gnu.org>)'.

   This option only has effect when the PDF output is produced with the
pdfTeX program, not with other ways of getting from Texinfo to PDF
(e.g., TeX to DVI to PDF).  Consequently, it is ok to specify this
option unconditionally within ‘@tex’, as shown above.  It is ignored
when DVI is being produced.


File: texinfo.info,  Node: @cite,  Next: PDF Colors,  Prev: @url,  Up: Cross References

5.15 ‘@cite’{REFERENCE}
=======================

Use the ‘@cite’ command for the name of a book that lacks a companion
Info file.  For example, we could refer to ‘A Book’.  The command
selects a slanted font in the printed manual, and generates quotation
marks in the Info file.

   If a book is written in Texinfo, it is better to use a
cross-reference command since a reader can easily follow such a
reference in Info.  *Note @xref::.


File: texinfo.info,  Node: PDF Colors,  Prev: @cite,  Up: Cross References

5.16 PDF Colors
===============

By default, URLs and cross-reference links are printed in black in PDF
output.  Very occasionally, however, you may want to highlight such
"live" links with a different color, as is commonly done on web pages.
Texinfo provides a PDF-specific option for specifying these colors,
which must be used inside ‘@tex’:

     @tex
     \global\def\linkcolor{1 0 0}  % red
     \global\def\urlcolor{0 1 0}   % green
     @end tex

   ‘\urlcolor’ changes the color of ‘@url’ output (both the actual URL
and any textual label), while ‘\linkcolor’ changes the color for
cross-references to nodes, etc.  They are independent.

   The three given values must be numbers between 0 and 1, specifying
the amount of red, green, and blue respectively.

   These definitions only have an effect when the PDF output is produced
with the pdfTeX program, not with other ways of getting from Texinfo to
PDF (e.g., TeX to DVI to PDF).  Consequently, it is ok to specify this
option unconditionally within ‘@tex’, as shown above.  It is ignored
when DVI is being produced.

   We do not recommend colorizing just for fun; unless you have a
specific reason to use colors, best to skip it.


File: texinfo.info,  Node: Marking Text,  Next: Quotations and Examples,  Prev: Cross References,  Up: Top

6 Marking Text, Words and Phrases
*********************************

In Texinfo, you can mark words and phrases in a variety of ways.  The
Texinfo processors use this information to determine how to highlight
the text.  You can specify, for example, whether a word or phrase is a
defining occurrence, a metasyntactic variable, or a symbol used in a
program.  Also, you can emphasize text, in several different ways.

* Menu:

* Indicating::                 How to indicate definitions, files, etc.
* Emphasis::                   How to emphasize text.


File: texinfo.info,  Node: Indicating,  Next: Emphasis,  Up: Marking Text

6.1 Indicating Definitions, Commands, etc.
==========================================

Texinfo has commands for indicating just what kind of object a piece of
text refers to.  For example, email addresses are marked by ‘@email’;
that way, the result can be a live link to send email when the output
format supports it.  If the email address was simply marked as "print in
a typewriter font", that would not be possible.

* Menu:

* Useful Highlighting::        Highlighting provides useful information.
* @code::                      Indicating program code.
* @kbd::                       Showing keyboard input.
* @key::                       Specifying keys.
* @samp::                      Indicating a literal sequence of characters.
* @verb::                      Indicating a verbatim sequence of characters.
* @var::                       Indicating metasyntactic variables.
* @env::                       Indicating environment variables.
* @file::                      Indicating file names.
* @command::                   Indicating command names.
* @option::                    Indicating option names.
* @dfn::                       Specifying definitions.
* @abbr::                      Indicating abbreviations.
* @acronym::                   Indicating acronyms.
* @indicateurl::               Indicating an example URL.
* @email::                     Indicating an electronic mail address.


File: texinfo.info,  Node: Useful Highlighting,  Next: @code,  Up: Indicating

6.1.1 Highlighting Commands are Useful
--------------------------------------

The commands serve a variety of purposes:

‘@code{SAMPLE-CODE}’
     Indicate text that is a literal example of a piece of a program.
     *Note @code::.

‘@kbd{KEYBOARD-CHARACTERS}’
     Indicate keyboard input.  *Note @kbd::.

‘@key{KEY-NAME}’
     Indicate the conventional name for a key on a keyboard.  *Note
     @key::.

‘@samp{TEXT}’
     Indicate text that is a literal example of a sequence of
     characters.  *Note @samp::.

‘@verb{TEXT}’
     Write a verbatim sequence of characters.  *Note @verb::.

‘@var{METASYNTACTIC-VARIABLE}’
     Indicate a metasyntactic variable.  *Note @var::.

‘@env{ENVIRONMENT-VARIABLE}’
     Indicate an environment variable.  *Note @env::.

‘@file{FILE-NAME}’
     Indicate the name of a file.  *Note @file::.

‘@command{COMMAND-NAME}’
     Indicate the name of a command.  *Note @command::.

‘@option{OPTION}’
     Indicate a command-line option.  *Note @option::.

‘@dfn{TERM}’
     Indicate the introductory or defining use of a term.  *Note @dfn::.

‘@cite{REFERENCE}’
     Indicate the name of a book.  *Note @cite::.

‘@abbr{ABBREVIATION}’
     Indicate an abbreviation, such as 'Comput.'.

‘@acronym{ACRONYM}’
     Indicate an acronym.  *Note @acronym::.

‘@indicateurl{UNIFORM-RESOURCE-LOCATOR}’
     Indicate an example (that is, nonfunctional) uniform resource
     locator.  *Note @indicateurl::.  (Use ‘@url’ (*note @url::) for
     live URLs.)

‘@email{EMAIL-ADDRESS[, DISPLAYED-TEXT]}’
     Indicate an electronic mail address.  *Note @email::.


File: texinfo.info,  Node: @code,  Next: @kbd,  Prev: Useful Highlighting,  Up: Indicating

6.1.2 ‘@code’{SAMPLE-CODE}
--------------------------

Use the ‘@code’ command to indicate text that is a piece of a program
and which consists of entire syntactic tokens.  Enclose the text in
braces.

   Thus, you should use ‘@code’ for an expression in a program, for the
name of a variable or function used in a program, or for a keyword in a
programming language.

   Use ‘@code’ for command names in languages that resemble programming
languages, such as Texinfo.  For example, ‘@code’ and ‘@samp’ are
produced by writing ‘@code{@@code}’ and ‘@code{@@samp}’ in the Texinfo
source, respectively.

   It is incorrect to alter the case of a word inside a ‘@code’ command
when it appears at the beginning of a sentence.  Most computer languages
are case sensitive.  In C, for example, ‘Printf’ is different from the
identifier ‘printf’, and most likely is a misspelling of it.  Even in
languages which are not case sensitive, it is confusing to a human
reader to see identifiers spelled in different ways.  Pick one spelling
and always use that.  If you do not want to start a sentence with a
command name written all in lowercase, you should rearrange the
sentence.

   The ‘@code’ argument is typeset in a typewriter (monospace) font.
where the output format allows this.  For example,

     The function returns @code{nil}.

produces this:

     The function returns ‘nil’.

   Here are some cases for which it is preferable _not_ to use ‘@code’:

   • For shell command names, such as ‘ls’ (use ‘@command’).

   • For environment variables, such as ‘TEXINPUTS’ (use ‘@env’).

   • For shell options, such as ‘-c’, when such options stand alone (use
     ‘@option’).

   • An entire shell command often looks better if written using ‘@samp’
     rather than ‘@code’.  In this case, the rule is to choose the more
     pleasing format.

   • For a string of characters shorter than a syntactic token.  For
     example, if you are writing about ‘goto-ch’, which is just a part
     of the name for the ‘goto-char’ Emacs Lisp function, you should use
     ‘@samp’.

   • In general, when writing about the characters used in a token; for
     example, do not use ‘@code’ when you are explaining what letters or
     printable symbols can be used in the names of functions.  (Use
     ‘@samp’.)  Also, you should not use ‘@code’ to mark text that is
     considered input to programs unless the input is written in a
     language that is like a programming language.  For example, you
     should not use ‘@code’ for the keystroke commands of GNU Emacs (use
     ‘@kbd’ instead) although you may use ‘@code’ for the names of the
     Emacs Lisp functions that the keystroke commands invoke.

   By default, TeX will consider breaking lines at ‘-’ and ‘_’
characters within ‘@code’ and related commands.  This can be controlled
with ‘@allowcodebreaks’ (*note @allowcodebreaks::).  In the HTML output
breaking lines is up to the browser's behavior.  For Info, it seems
better never to make such breaks.

   For Info and plaintext, quotation characters are usually output
around the output of the ‘@code’ command and related commands (e.g.,
‘@kbd’, ‘@command’) except in typewriter-like contexts such as the
‘@example’ environment (*note @example::) and ‘@code’ itself, etc.  To
control which quoting characters are inserted by ‘texi2any’ in the
output of ‘@code’, etc., see the ‘OPEN_QUOTE_SYMBOL’ and
‘CLOSE_QUOTE_SYMBOL’ customization variables (*note Customization
Variables for Multiple Formats::).


File: texinfo.info,  Node: @kbd,  Next: @key,  Prev: @code,  Up: Indicating

6.1.3 ‘@kbd’{KEYBOARD-CHARACTERS}
---------------------------------

Use the ‘@kbd’ command for characters of input to be typed by users.
For example, to refer to the characters ‘M-a’, write:

     @kbd{M-a}

and to refer to the characters ‘M-x shell’, write:

     @kbd{M-x shell}

   By default, the ‘@kbd’ command produces a different font (slanted
typewriter instead of normal typewriter, where the output format
allows), so users can distinguish the characters that they are supposed
to type from those that the computer outputs.

   Since the usage of ‘@kbd’ varies from manual to manual, you can
control the font switching with the ‘@kbdinputstyle’ command.  This
command has no effect on Info output.  Write this command at the
beginning of a line with a single word as an argument, one of the
following:

‘code’
     Always use the same font for ‘@kbd’ as ‘@code’.
‘example’
     Use the distinguishing font for ‘@kbd’ only in ‘@example’ and
     similar environments.
‘distinct’
     (the default) Always use the distinguishing font for ‘@kbd’.

   You can embed another @-command inside the braces of a ‘@kbd’
command.  Here, for example, is the way to describe a command that would
be described more verbosely as "press the ‘r’ key and then press the
<RETURN> key":

     @kbd{r @key{RET}}

This produces: ‘r <RET>’.  (The present manual uses the default for
‘@kbdinputstyle’.)

   You also use the ‘@kbd’ command if you are spelling out the letters
you type; for example:

     To give the @code{logout} command,
     type the characters @kbd{l o g o u t @key{RET}}.

This produces:

     To give the ‘logout’ command, type the characters ‘l o g o u t
     <RET>’.

   (Also, this example shows that you can add spaces for clarity.  If
you explicitly want to mention a space character as one of the
characters of input, write ‘@key{SPC}’ for it.)


File: texinfo.info,  Node: @key,  Next: @samp,  Prev: @kbd,  Up: Indicating

6.1.4 ‘@key’{KEY-NAME}
----------------------

Use the ‘@key’ command for the conventional name for a key on a
keyboard, as in:

     @key{RET}

   You can use the ‘@key’ command within the argument of an ‘@kbd’
command when the sequence of characters to be typed includes one or more
keys that are described by name.

   For example, to produce ‘C-x <ESC>’ and ‘M-<TAB>’ you would type:

     @kbd{C-x @key{ESC}}
     @kbd{M-@key{TAB}}

   Here is a list of the recommended names for keys:

     SPC
          Space
     RET
          Return
     LFD
          Linefeed (however, since most keyboards nowadays do not have a
          Linefeed key, it might be better to call this character ‘C-j’)
     TAB
          Tab
     BS
          Backspace
     ESC
          Escape
     DELETE
          Delete
     SHIFT
          Shift
     CTRL
          Control
     META
          Meta

   There are subtleties to handling words like 'meta' or 'ctrl' that are
names of modifier keys.  When mentioning a character in which the
modifier key is used, such as ‘Meta-a’, use the ‘@kbd’ command alone; do
not use the ‘@key’ command; but when you are referring to the modifier
key in isolation, use the ‘@key’ command.  For example, write
‘@kbd{Meta-a}’ to produce ‘Meta-a’ and ‘@key{META}’ to produce <META>.


File: texinfo.info,  Node: @samp,  Next: @verb,  Prev: @key,  Up: Indicating

6.1.5 ‘@samp’{TEXT}
-------------------

Use the ‘@samp’ command to indicate text that is a literal example or
'sample' of a sequence of characters in a file, string, pattern, etc.
Enclose the text in braces.  The argument appears within single
quotation marks; in addition, it is printed in a fixed-width font.

     To match @samp{foo} at the end of the line,
     use the regexp @samp{foo$}.

produces

     To match ‘foo’ at the end of the line, use the regexp ‘foo$’.

   Any time you are referring to single characters, you should use
‘@samp’ unless ‘@kbd’ or ‘@key’ is more appropriate.  Also, you may use
‘@samp’ for entire statements in C and for entire shell commands--in
this case, ‘@samp’ often looks better than ‘@code’.  Basically, ‘@samp’
is a catchall for whatever is not covered by ‘@code’, ‘@kbd’, ‘@key’,
‘@command’, etc.

   Only include punctuation marks within braces if they are part of the
string you are specifying.  Write punctuation marks outside the braces
if those punctuation marks are part of the English text that surrounds
the string.  In the following sentence, for example, the commas and
period are outside of the braces:

     In English, the vowels are @samp{a}, @samp{e},
     @samp{i}, @samp{o}, @samp{u}, and sometimes
     @samp{y}.

This produces:

     In English, the vowels are ‘a’, ‘e’, ‘i’, ‘o’, ‘u’, and sometimes
     ‘y’.


File: texinfo.info,  Node: @verb,  Next: @var,  Prev: @samp,  Up: Indicating

6.1.6 ‘@verb’{CHARTEXTCHAR}
---------------------------

Use the ‘@verb’ command to print a verbatim sequence of characters.

   Like LaTeX's ‘\verb’ command, the verbatim text can be quoted using
any unique delimiter character.  Enclose the verbatim text, including
the delimiters, in braces.  Text is printed in a fixed-width font:

     How many @verb{|@|}-escapes does one need to print this
     @verb{.@a @b.@c.} string or @verb{+@'e?`{}!`\+} this?

produces

     How many @-escapes does one need to print this
     @a @b.@c string or @'e?`{}!`\ this?

   This is in contrast to ‘@samp’ (see the previous section), ‘@code’,
and similar commands; in those cases, the argument is normal Texinfo
text, where the three characters ‘@{}’ are special, as usual.  With
‘@verb’, nothing is special except the delimiter character you choose.

   The delimiter character itself may appear inside the verbatim text,
as shown above.  As another example, ‘@verb{...}’ prints a single
(fixed-width) period.

   It is not reliable to use ‘@verb’ inside other Texinfo constructs.
In particular, it does not work to use ‘@verb’ in anything related to
cross-referencing, such as section titles or figure captions.


File: texinfo.info,  Node: @var,  Next: @env,  Prev: @verb,  Up: Indicating

6.1.7 ‘@var’{METASYNTACTIC-VARIABLE}
------------------------------------

Use the ‘@var’ command to indicate metasyntactic variables.  A
“metasyntactic variable” is something that stands for another piece of
text.  For example, you should use a metasyntactic variable in the
documentation of a function to describe the arguments that are passed to
that function.

   Do not use ‘@var’ for the names of normal variables in computer
programs.  These are specific names, so ‘@code’ is correct for them.
For example, the Emacs Lisp variable ‘texinfo-tex-command’ is not a
metasyntactic variable; it is properly formatted using ‘@code’.

   Do not use ‘@var’ for environment variables either; ‘@env’ is correct
for them (see the next section).

   The effect of ‘@var’ in the Info file is to change the case of the
argument to all uppercase.  In the printed manual, the argument is
output in slanted type.  (1)

   For example,

     To delete file @var{filename},
     type @samp{rm @var{filename}}.

produces

     To delete file FILENAME, type ‘rm FILENAME’.

(Note that ‘@var’ may appear inside ‘@code’, ‘@samp’, ‘@file’, etc.)

   Write a metasyntactic variable all in lowercase without spaces, and
use hyphens to make it more readable.  Thus, the Texinfo source for the
illustration of how to begin a Texinfo manual looks like this:

     \input texinfo
     @@settitle @var{name-of-manual}

This produces:

     \input texinfo
     @settitle NAME-OF-MANUAL

   In some documentation styles, metasyntactic variables are shown with
angle brackets, for example:

     ..., type rm <filename>

However, that is not the style that Texinfo uses.

   ---------- Footnotes ----------

   (1) In TeX output, ‘@var’ currently uses a slanted typewriter font in
code contexts such as ‘@code’ or ‘@example’.  We plan to change this in
the next release to use a variable-width, slanted roman font in all
contexts.  To avoid this change, set the ‘txicodevaristt’ flag using
‘@set’; specify ‘@clear txicodevaristt’ to make this change now (*note
@set @value::).  Note that this flag does nothing in LaTeX output.


File: texinfo.info,  Node: @env,  Next: @file,  Prev: @var,  Up: Indicating

6.1.8 ‘@env’{ENVIRONMENT-VARIABLE}
----------------------------------

Use the ‘@env’ command to indicate environment variables, as used by
many operating systems, including GNU.  Do not use it for
_meta_syntactic variables; use ‘@var’ for those (see the previous
section).

   ‘@env’ is equivalent to ‘@code’ in its effects.  For example:

     The @env{PATH} environment variable ...
produces
     The ‘PATH’ environment variable ...


File: texinfo.info,  Node: @file,  Next: @command,  Prev: @env,  Up: Indicating

6.1.9 ‘@file’{FILE-NAME}
------------------------

Use the ‘@file’ command to indicate text that is the name of a file,
buffer, or directory, or is the name of a node in Info.  You can also
use the command for file name suffixes.  Do not use ‘@file’ for symbols
in a programming language; use ‘@code’.

   ‘@file’ is equivalent to ‘code’ in its effects.  For example,

     The @file{.el} files are in
     the @file{/usr/local/emacs/lisp} directory.

produces

     The ‘.el’ files are in the ‘/usr/local/emacs/lisp’ directory.


File: texinfo.info,  Node: @command,  Next: @option,  Prev: @file,  Up: Indicating

6.1.10 ‘@command’{COMMAND-NAME}
-------------------------------

Use the ‘@command’ command to indicate command names, such as ‘ls’ or
‘cc’.

   ‘@command’ is equivalent to ‘@code’ in its effects.  For example:

     The command @command{ls} lists directory contents.
produces
     The command ‘ls’ lists directory contents.

   You should write the name of a program in the ordinary text font,
rather than using ‘@command’, if you regard it as a new English word,
such as 'Emacs' or 'Bison'.

   When writing an entire shell command invocation, as in ‘ls -l’, you
should use either ‘@samp’ or ‘@code’ at your discretion.


File: texinfo.info,  Node: @option,  Next: @dfn,  Prev: @command,  Up: Indicating

6.1.11 ‘@option’{OPTION-NAME}
-----------------------------

Use the ‘@option’ command to indicate a command-line option; for
example, ‘-l’ or ‘--version’ or ‘--output=FILENAME’.

   ‘@option’ is equivalent to ‘@code’ in its effects.  For example:

     The option @option{-l} produces a long listing.
produces
     The option ‘-l’ produces a long listing.


File: texinfo.info,  Node: @dfn,  Next: @abbr,  Prev: @option,  Up: Indicating

6.1.12 ‘@dfn’{TERM}
-------------------

Use the ‘@dfn’ command to identify the introductory or defining use of a
technical term.  Use the command only in passages whose purpose is to
introduce a term which will be used again or which the reader ought to
know.  Mere passing mention of a term for the first time does not
deserve ‘@dfn’.  The command selects a slanted font in the printed
manual, and generates double quotation marks in the Info file.  For
example:

     Getting rid of a file is called @dfn{deleting} it.

produces

     Getting rid of a file is called “deleting” it.

   As a general rule, a sentence containing the defining occurrence of a
term should be a definition of the term.  The sentence does not need to
say explicitly that it is a definition, but it should contain the
information of a definition--it should make the meaning clear.


File: texinfo.info,  Node: @abbr,  Next: @acronym,  Prev: @dfn,  Up: Indicating

6.1.13 ‘@abbr’{ABBREVIATION[, MEANING]}
---------------------------------------

You can use the ‘@abbr’ command for general abbreviations.  The
abbreviation is given as the single argument in braces, as in
‘@abbr{Comput.}’.  As a matter of style, or for particular
abbreviations, you may prefer to omit periods, as in ‘@abbr{Mr}
Stallman’.

   ‘@abbr’ accepts an optional second argument, intended to be used for
the meaning of the abbreviation.

   If the abbreviation ends with a lowercase letter and a period, and is
not at the end of a sentence, and has no second argument, remember to
use the ‘@.’ command (*note Ending a Sentence::) to get the correct
spacing.  However, you do not have to use ‘@.’ within the abbreviation
itself; Texinfo automatically assumes periods within the abbreviation do
not end a sentence.

   In output formats with an appropriate tag, such as HTML and DocBook,
this tag is used.  Otherwise, the first argument is printed as-is; if
the second argument is present, it is printed in parentheses after the
abbreviation.  For instance:

     @abbr{Comput. J., Computer Journal}

produces:

     Comput. J. (Computer Journal)

   For abbreviations consisting of all capital letters, you may prefer
to use the ‘@acronym’ command instead.  See the next section for more on
the usage of these two commands.


File: texinfo.info,  Node: @acronym,  Next: @indicateurl,  Prev: @abbr,  Up: Indicating

6.1.14 ‘@acronym’{ACRONYM[, MEANING]}
-------------------------------------

You can use the ‘@acronym’ command for abbreviations written in all
capital letters, such as 'NASA'.  The abbreviation is given as the
single argument in braces, as in ‘@acronym{NASA}’.  As a matter of
style, or for particular acronyms, you may prefer to use periods, as in
‘@acronym{N.A.S.A.}’.

   ‘@acronym’ accepts an optional second argument, intended to be used
for the meaning of the acronym.

   If the acronym is at the end of a sentence, and if there is no second
argument, remember to use the ‘@.’ or similar command (*note Ending a
Sentence::) to get the correct spacing.

   In TeX, the acronym is printed in slightly smaller font.  In the Info
output, the argument is printed as-is.  In either format, and in LaTeX
output, if the second argument is present, it is printed in parentheses
after the acronym.  In HTML and DocBook the appropriate tag is used.

   For instance (since GNU is a recursive acronym, we use ‘@acronym’
recursively):

     @acronym{GNU, @acronym{GNU}'s Not Unix}

produces:

     GNU (GNU's Not Unix)

   In some circumstances, it is conventional to print family names in
all capitals.  Don't use ‘@acronym’ for this, since a name is not an
acronym.  Use ‘@sc’ instead (*note Smallcaps::).

   ‘@abbr’ and ‘@acronym’ are closely related commands: they both signal
to the reader that a shortened form is being used, and possibly give a
meaning.  When choosing whether to use these two commands, please bear
the following in mind.

   − In common English usage, acronyms are a subset of abbreviations:
     they include pronounceable words like 'NATO', 'radar', and 'snafu';
     some sources also include syllable acronyms like 'Usenet', hybrids
     like 'SIGGRAPH', and unpronounceable initialisms like 'FBI'.

   − In Texinfo, an acronym (but not an abbreviation) should consist
     only of capital letters and periods, no lowercase.

   − In TeX, an acronym (but not an abbreviation) is printed in a
     slightly smaller font.

   − It usually turns out to be quite difficult and/or time-consuming to
     consistently use ‘@acronym’ for all sequences of uppercase letters.
     Furthermore, it looks strange for some acronyms to be in the normal
     font size and others to be smaller.  Thus, a simpler approach you
     may wish to consider is to avoid ‘@acronym’ and just typeset
     everything as normal text in all capitals: ‘GNU’, producing the
     output 'GNU'.

   − In general, it's not essential to use either of these commands for
     all abbreviations; use your judgment.  Text is perfectly readable
     without them.


File: texinfo.info,  Node: @indicateurl,  Next: @email,  Prev: @acronym,  Up: Indicating

6.1.15 ‘@indicateurl’{UNIFORM-RESOURCE-LOCATOR}
-----------------------------------------------

Use the ‘@indicateurl’ command to indicate a uniform resource locator on
the World Wide Web.  This is purely for markup purposes and does not
produce a link you can follow (use the ‘@url’ or ‘@uref’ command for
that, *note @url::).  ‘@indicateurl’ is useful for URLs which do not
actually exist.  For example:

     For example, the URL might be @indicateurl{http://example.org/path}.

which produces:

     For example, the URL might be ‘http://example.org/path’.

   The output from ‘@indicateurl’ is usually like that of ‘@samp’ (*note
@samp::).


File: texinfo.info,  Node: @email,  Prev: @indicateurl,  Up: Indicating

6.1.16 ‘@email’{EMAIL-ADDRESS[, DISPLAYED-TEXT]}
------------------------------------------------

Use the ‘@email’ command to indicate an electronic mail address.  It
takes one mandatory argument, the address, and one optional argument,
the text to display (the default is the address itself).

   In Info, the address is shown in angle brackets, preceded by the text
to display if any.  In printed output, the angle brackets are omitted.
In HTML and DocBook output, ‘@email’ produces a ‘mailto’ link.  In HTML,
a ‘mailto’ link usually brings up a mail composition window.  For
example:

     Send bug reports to @email{bug-texinfo@@gnu.org},
     suggestions to the @email{bug-texinfo@@gnu.org, same place}.

produces

     Send bug reports to <bug-texinfo@gnu.org>,
     suggestions to the same place <bug-texinfo@gnu.org>.


File: texinfo.info,  Node: Emphasis,  Prev: Indicating,  Up: Marking Text

6.2 Emphasizing Text
====================

Usually, Texinfo changes the font to mark words in the text according to
the category the words belong to; an example is the ‘@code’ command.
Most often, this is the best way to mark words.  However, sometimes you
will want to emphasize text without indicating a category.  Texinfo has
two commands to do this.  Also, Texinfo has several commands that
specify the font in which text will be output.  These commands have no
effect in Info and only one of them, the ‘@r’ command, has any regular
use.

* Menu:

* @emph @strong::              How to emphasize text in Texinfo.
* Smallcaps::                  How to use the small caps font.
* Fonts::                      Various font commands for printed output.


File: texinfo.info,  Node: @emph @strong,  Next: Smallcaps,  Up: Emphasis

6.2.1 ‘@emph’{TEXT} and ‘@strong’{TEXT}
---------------------------------------

The ‘@emph’ and ‘@strong’ commands are for emphasis; ‘@strong’ is
stronger.  In printed output, ‘@emph’ produces _italics_ and ‘@strong’
produces *bold*.  In the Info output, ‘@emph’ surrounds the text with
underscores (‘_’), and ‘@strong’ puts asterisks around the text.

   For example,

     @strong{Caution:} @samp{rm * .[^.]*}
     removes @emph{all} files in the directory.

produces the following:

     *Caution*: ‘rm * .[^.]*’ removes _all_ files in the directory.

   The ‘@strong’ command is seldom used except to mark what is, in
effect, a typographical element, such as the word 'Caution' in the
preceding example.

     Caution: Do not use ‘@strong’ with the word ‘Note’ followed by a
     space; Info will mistake the combination for a cross-reference.
     Use a phrase such as *Please notice* or *Caution* instead, or the
     optional argument to ‘@quotation’--‘Note’ is allowable there.


File: texinfo.info,  Node: Smallcaps,  Next: Fonts,  Prev: @emph @strong,  Up: Emphasis

6.2.2 ‘@sc’{TEXT}: The Small Caps Font
--------------------------------------

Use the ‘@sc’ command to set text in A SMALL CAPS FONT (where possible).
Write the text you want to be in small caps between braces in lowercase,
like this:

     Richard @sc{Stallman} a commencé le projet GNU.

This produces:

     Richard STALLMAN a commencé le projet GNU.

   As shown here, we recommend reserving ‘@sc’ for special cases where
you want typographic small caps; family names are one such, especially
in languages other than English, though there are no hard-and-fast rules
about such things.

   TeX typesets any uppercase letters between the braces of an ‘@sc’
command in full-size capitals; only lowercase letters are printed in the
small caps font.  In the Info output, the argument to ‘@sc’ is printed
in all uppercase.  In HTML, the argument is uppercased and the output
marked with the ‘<small>’ tag to reduce the font size, since HTML cannot
easily represent true small caps.  In LaTeX, a command setting small
caps fonts is output.

   Overall, we recommend using standard upper- and lowercase letters
wherever possible.


File: texinfo.info,  Node: Fonts,  Prev: Smallcaps,  Up: Emphasis

6.2.3 Fonts for Printing
------------------------

Texinfo provides one command to change the size of the main body font in
printed output for a document: ‘@fonttextsize’.  It has no effect in
other output.  It takes a single argument on the remainder of the line,
which must be either ‘10’ or ‘11’.  For example:

     @fonttextsize 10

   The effect is to reduce the body font to a 10pt size (the default is
11pt).  Fonts for other elements, such as sections and chapters, are
reduced accordingly.  This should only be used in conjunction with
‘@smallbook’ (*note @smallbook::) or similar, since 10pt fonts on
standard paper (8.5x11 or A4) are too small.  One reason to use this
command is to save pages, and hence printing cost, for physical books.

   Texinfo does not at present have commands to switch the font family
to use, or more general size-changing commands.

   Texinfo also provides a number of font commands that specify font
changes in the printed manual and (where possible) in the HTML and
DocBook output.  They have no effect in Info.  All the commands apply to
a following argument surrounded by braces.

‘@b’
     selects bold face;

‘@i’
     selects an italic font;

‘@r’
     selects a roman font, which is the usual font in which text is
     printed.  It may or may not be seriffed.

‘@sansserif’
     selects a sans serif font;

‘@slanted’
     selects a slanted font;

‘@t’
     selects the fixed-width, typewriter-style font used by ‘@code’;

   The ‘@r’ command can be useful in example-like environments, to write
comments in the standard roman font instead of the fixed-width font.
This looks better in printed output.

   For example,

     @lisp
     (+ 2 2)    ; @r{Add two plus two.}
     @end lisp

produces

     (+ 2 2)    ; Add two plus two.

   The ‘@t’ command can occasionally be useful for producing output in a
typewriter font where that is supported, but no distinction with
quotation marks is needed in Info or plain text.  (Compare ‘@t{foo}’
producing foo with ‘@code{foo}’ producing ‘foo’.)  Here are some
possible reasons for using ‘@t’ instead of ‘@code’:

   − The argument is a single character
   − There are already quotes of some kind enclosing the argument
   − It's evident from context or the argument itself that the argument
     could be computer code (e.g. name of a Usenet newsgroup)

   In general, the other font commands are unlikely to be useful; they
exist primarily to make it possible to document the functionality of
specific font effects, such as in TeX and related packages.


File: texinfo.info,  Node: Quotations and Examples,  Next: Lists and Tables,  Prev: Marking Text,  Up: Top

7 Quotations and Examples
*************************

Quotations and examples are blocks of text consisting of one or more
whole paragraphs that are set off from the bulk of the text and treated
differently.  They are usually indented in the output.

   In Texinfo, you always begin a quotation or example by writing an
@-command at the beginning of a line by itself, and end it by writing an
‘@end’ command that is also at the beginning of a line by itself.  For
instance, you begin an example by writing ‘@example’ by itself at the
beginning of a line and end the example by writing ‘@end example’ on a
line by itself, at the beginning of that line, and with only one space
between the ‘@end’ and the ‘example’.

* Menu:

* Block Enclosing Commands::   Different constructs for different purposes.
* @quotation::                 Writing a quotation.
* @indentedblock::             Block of text indented on left.
* @example::                   Writing an example in a fixed-width font.
* @verbatim::                  Writing a verbatim example.
* @lisp::                      Illustrating Lisp code.
* @display::                   Writing an example in the current font.
* @format::                    Writing an example without narrowed margins.
* @exdent::                    Undo indentation on a line.
* @flushleft @flushright::     Pushing text flush left or flush right.
* @raggedright::               Avoiding justification on the right.
* @noindent::                  Preventing paragraph indentation.
* @indent::                    Forcing paragraph indentation.
* @cartouche::                 Drawing rounded rectangles around text.
* small::                      Examples in a smaller font.


File: texinfo.info,  Node: Block Enclosing Commands,  Next: @quotation,  Up: Quotations and Examples

7.1 Block Enclosing Commands
============================

Here is a summary of commands that enclose blocks of text, also known as
“environments”.  They're explained further in the following sections.

‘@quotation’
     Indicate text that is quoted.  The text is filled, indented (from
     both margins), and printed in a roman font by default.

‘@indentedblock’
     Like ‘@quotation’, but the text is indented only on the left.

‘@example’
     Illustrate code, commands, and the like.  The text is printed in a
     fixed-width font, and indented but not filled.

‘@lisp’
     Like ‘@example’, but specifically for illustrating Lisp code.  The
     text is printed in a fixed-width font, and indented but not filled.

‘@verbatim’
     Mark a piece of text that is to be printed verbatim; no character
     substitutions are made and all commands are ignored, until the next
     ‘@end verbatim’.  The text is printed in a fixed-width font, and
     not indented or filled.  Extra spaces and blank lines are
     significant, and tabs are expanded.

‘@display’
     Display illustrative text.  The text is indented but not filled,
     and no font is selected (so, by default, the font is roman).

‘@format’
     Like ‘@display’ (the text is not filled and no font is selected),
     but the text is not indented.

‘@smallquotation’
‘@smallindentedblock’
‘@smallexample’
‘@smalllisp’
‘@smalldisplay’
‘@smallformat’
     These ‘@small...’ commands are just like their non-small
     counterparts, except that they output text in a smaller font size,
     where possible.

‘@flushleft’
‘@flushright’
     Text is not filled, but is set flush with the left or right margin,
     respectively.

‘@raggedright’
     Text is filled, but only justified on the left, leaving the right
     margin ragged.

‘@cartouche’
     Highlight text, often an example or quotation, by drawing a box
     with rounded corners around it.

   The ‘@exdent’ command is used within the above constructs to undo the
indentation of a line.

   The ‘@noindent’ command may be used after one of the above constructs
(or at the beginning of any paragraph) to prevent the following text
from being indented as a new paragraph.


File: texinfo.info,  Node: @quotation,  Next: @indentedblock,  Prev: Block Enclosing Commands,  Up: Quotations and Examples

7.2 ‘@quotation’: Block Quotations
==================================

The text of a quotation is processed like normal text (regular font,
text is filled) except that:

   • the left margin is closer to the center of the page, so the whole
     of the quotation is indented; the right margin may also be closer
     to the center of the page

   • the first lines of paragraphs are indented no more than other
     lines; and

   • an ‘@author’ command may be given to specify the author of the
     quotation.

     This is an example of text written between a ‘@quotation’ command
     and an ‘@end quotation’ command.  A ‘@quotation’ command is most
     often used to indicate text that is excerpted from another (real or
     hypothetical) printed work.

   Write a ‘@quotation’ command as text on a line by itself.  This line
will disappear from the output.  Mark the end of the quotation with a
line beginning with and containing only ‘@end quotation’.  The ‘@end
quotation’ line will likewise disappear from the output.

   ‘@quotation’ takes one optional argument, given on the remainder of
the line.  This text, if present, is included at the beginning of the
quotation in bold or otherwise emphasized, and followed with a ‘:’.  For
example:

     @quotation Note
     This is
     a foo.
     @end quotation

produces

     Note: This is a foo.

   If the ‘@quotation’ argument is one of these English words
(case-insensitive):

     Caution  Important  Note  Tip  Warning

then the DocBook output uses corresponding special tags (‘<note>’, etc.)
instead of the default ‘<blockquote>’.

   If the author of the quotation is specified in the ‘@quotation’ block
with the ‘@author’ command, a line with the author name is displayed
after the quotation:

     @quotation
     People sometimes ask me if it is a sin in the Church of Emacs to use
     vi.  Using a free version of vi is not a sin; it is a penance.  So happy
     hacking.

     @author Richard Stallman
     @end quotation

produces

     People sometimes ask me if it is a sin in the Church of Emacs to
     use vi.  Using a free version of vi is not a sin; it is a penance.
     So happy hacking.

                         -- _Richard Stallman_


File: texinfo.info,  Node: @indentedblock,  Next: @example,  Prev: @quotation,  Up: Quotations and Examples

7.3 ‘@indentedblock’: Indented text blocks
==========================================

The ‘@indentedblock’ environment is similar to ‘@quotation’, except that
text is only indented on the left (and there is no optional argument for
an author).  Thus, the text font remains unchanged, and text is gathered
and filled as usual, but the left margin is increased.  For example:

     This is an example of text written between an ‘@indentedblock’
     command and an ‘@end indentedblock’ command.  The ‘@indentedblock’
     environment can contain any text or other commands desired.

   This is written in the Texinfo source as:

     @indentedblock
     This is an example ...
     @end indentedblock


File: texinfo.info,  Node: @example,  Next: @verbatim,  Prev: @indentedblock,  Up: Quotations and Examples

7.4 ‘@example’: Example Text
============================

The ‘@example’ environment is used to indicate computer input or output
that is not part of the running text.  If you want to embed code
fragments within sentences, use the ‘@code’ command or its relatives
instead (*note @code::).

   Write an ‘@example’ command at the beginning of a line by itself.
Mark the end of the block with ‘@end example’.  For example,

     @example
     cp foo @var{dest1}; \
      cp foo @var{dest2}
     @end example

produces

     cp foo DEST1; \
      cp foo DEST2

   The output uses a fixed-width font and is indented.  Each line in the
input file is a line in the output; that is, the source text is not
filled.  Extra spaces and blank lines are significant.  Texinfo commands
_are_ expanded; if you want the output to be the input verbatim, use the
‘@verbatim’ environment instead (*note @verbatim::).

   Examples are often, logically speaking, "in the middle" of a
paragraph, and the text that continues afterwards should not be
indented, as in the example above.  The ‘@noindent’ command prevents a
piece of text from being indented as if it were a new paragraph (*note
@noindent::).

   If you wish to use the normal roman font for a code comment, you can
use the ‘@r’ command (*note Fonts::).

   You may optionally give arguments to the ‘@example’ command,
separated by commas if there is more than one.  In the HTML output, any
such arguments are output as class names, prefixed by the string
‘user-’.  This may be useful for adding syntax highlighting to manuals
for code samples.

   We recommend that when you give multiple arguments to ‘@example’, you
use the first argument to specify the language of the code (e.g. ‘C’,
‘lisp’, ‘Cplusplus’).  You may find uses for other arguments, such as
providing a formatting hint or marking code samples for extraction and
further processing, but for now nothing definitive is recommended.
Perhaps this will change in future Texinfo releases.

     Caution: Do not use tabs in the lines of an example!  (Or anywhere
     else in Texinfo, except in verbatim environments.)  TeX treats tabs
     as single spaces, and that is not what they look like.


File: texinfo.info,  Node: @verbatim,  Next: @lisp,  Prev: @example,  Up: Quotations and Examples

7.5 ‘@verbatim’: Literal Text
=============================

Use the ‘@verbatim’ environment for printing of text that may contain
special characters or commands that should not be interpreted, such as
computer input or output (‘@example’ interprets its text as regular
Texinfo commands).  This is especially useful for including
automatically generated files in a Texinfo manual.

   In general, the output will be just the same as the input.  No
character substitutions are made, e.g., all spaces and blank lines are
significant, including tabs.  The text is typeset in a fixed-width font,
and not indented or filled.

   Write a ‘@verbatim’ command at the beginning of a line by itself.
This line will disappear from the output.  Mark the end of the verbatim
block with an ‘@end verbatim’ command, also written at the beginning of
a line by itself.  The ‘@end verbatim’ will also disappear from the
output.

   For example:

     @verbatim
     {
     <TAB>@command with strange characters: @'e
     expand<TAB>me
     }
     @end verbatim

(where <TAB> stands for a literal tab character).  This produces:

{
	@command with strange characters: @'e
expand	me
}

   Since the lines containing ‘@verbatim’ and ‘@end verbatim’ produce no
output, typically you should put a blank line before the ‘@verbatim’ and
another blank line after the ‘@end verbatim’.  Blank lines between the
beginning ‘@verbatim’ and the ending ‘@end verbatim’ will appear in the
output.

   You can get a "small" verbatim by enclosing the ‘@verbatim’ in an
‘@smallformat’ environment, as shown here:

     @smallformat
     @verbatim
     ... still verbatim, but in a smaller font ...
     @end verbatim
     @end smallformat

   Finally, a word of warning: it is not reliable to use ‘@verbatim’
inside other Texinfo constructs.

   See also *note @verbatiminclude::.


File: texinfo.info,  Node: @lisp,  Next: @display,  Prev: @verbatim,  Up: Quotations and Examples

7.6 ‘@lisp’: Marking a Lisp Example
===================================

The ‘@lisp’ command was used for Lisp code:

     @lisp
     Example lisp code
     @end lisp

This is now synonymous with the following:

     @example lisp
     Example lisp code
     @end example

   Use ‘@lisp’ to preserve information regarding the nature of the
example.  This is useful, for example, if you write a function that
evaluates only and all the Lisp code in a Texinfo file.  Then you can
use the Texinfo file as a Lisp library.


File: texinfo.info,  Node: @display,  Next: @format,  Prev: @lisp,  Up: Quotations and Examples

7.7 ‘@display’: Examples Using the Text Font
============================================

The ‘@display’ command begins another kind of environment, where the
font is left unchanged, not switched to typewriter as with ‘@example’.
Each line of input still produces a line of output, and the output is
still indented.

     This is an example of text written between a ‘@display’ command
     and an ‘@end display’ command.  The ‘@display’ command
     indents the text, but does not fill it.


File: texinfo.info,  Node: @format,  Next: @exdent,  Prev: @display,  Up: Quotations and Examples

7.8 ‘@format’: Examples Using the Full Line Width
=================================================

The ‘@format’ command is similar to ‘@display’, except it leaves the
text unindented.  Like ‘@display’, it does not select the fixed-width
font.  Thus,

     @format
     This is an example of text written between a @code{@@format} command
     and an @code{@@end format} command.  As you can see
     from this example,
     the @code{@@format} command does not fill the text.
     @end format

produces

This is an example of text written between a ‘@format’ command
and an ‘@end format’ command.  As you can see
from this example,
the ‘@format’ command does not fill the text.


File: texinfo.info,  Node: @exdent,  Next: @flushleft @flushright,  Prev: @format,  Up: Quotations and Examples

7.9 ‘@exdent’: Undoing a Line's Indentation
===========================================

The ‘@exdent’ command removes any indentation a line might have.  The
command is written at the beginning of a line and applies only to the
text that follows the command that is on the same line.  Do not use
braces around the text.  The text on an ‘@exdent’ line is also printed
in the roman font where the output format allows this.

   ‘@exdent’ is usually used within examples.  Thus,

     @example
     This line follows an @@example command.
     @exdent This line is exdented.
     This line follows the exdented line.
     The @@end example comes on the next line.
     @end example

produces

     This line follows an @example command.
This line is exdented.
     This line follows the exdented line.
     The @end example comes on the next line.

   In practice, the ‘@exdent’ command is rarely used.  Usually, you
un-indent text by ending the example and returning the page to its
normal width.

   ‘@exdent’ does not have an effect in all output formats.


File: texinfo.info,  Node: @flushleft @flushright,  Next: @raggedright,  Prev: @exdent,  Up: Quotations and Examples

7.10 ‘@flushleft’ and ‘@flushright’
===================================

The ‘@flushleft’ and ‘@flushright’ commands line up the ends of lines on
the left and right margins of a page, but do not fill the text.  The
commands are written on lines of their own, without braces.  The
‘@flushleft’ and ‘@flushright’ commands are ended by ‘@end flushleft’
and ‘@end flushright’ commands on lines of their own.

   For example,

     @flushleft
     This text is
     written flushleft.
     @end flushleft

produces

     This text is
     written flushleft.

   ‘@flushright’ produces the type of indentation often used in the
return address of letters.  For example,

     @flushright
     Here is an example of text written
     flushright.  The @code{@flushright} command
     right justifies every line but leaves the
     left end ragged.
     @end flushright

produces

                                     Here is an example of text written
                                 flushright.  The ‘@flushright’ command
                              right justifies every line but leaves the
                                                       left end ragged.


File: texinfo.info,  Node: @raggedright,  Next: @noindent,  Prev: @flushleft @flushright,  Up: Quotations and Examples

7.11 ‘@raggedright’: Ragged Right Text
======================================

The ‘@raggedright’ fills text as usual, but the text is only justified
on the left; the right margin is ragged.  The command is written on a
line of its own, without braces.  The ‘@raggedright’ command is ended by
‘@end raggedright’ on a line of its own.  This command only has an
effect in output formats where text is justified on the left, but not in
output formats where text is always set ragged right, such as Info or
HTML.

   The ‘@raggedright’ command can be useful with paragraphs containing
lists of commands with long names, when it is known in advance that
justifying the text on both margins will make the paragraph look bad.

   An example (from elsewhere in this manual):

     @raggedright
     Commands for double and single angle quotation marks:
     @code{@@guillemetleft@{@}}, @code{@@guillemetright@{@}},
     @code{@@guillemotleft@{@}}, @code{@@guillemotright@{@}},
     @code{@@guilsinglleft@{@}}, @code{@@guilsinglright@{@}}.
     @end raggedright

produces

   Commands for double and single angle quotation marks:
‘@guillemetleft{}’, ‘@guillemetright{}’, ‘@guillemotleft{}’,
‘@guillemotright{}’, ‘@guilsinglleft{}’, ‘@guilsinglright{}’.


File: texinfo.info,  Node: @noindent,  Next: @indent,  Prev: @raggedright,  Up: Quotations and Examples

7.12 ‘@noindent’: Omitting Indentation
======================================

An example or other inclusion can break a paragraph into segments.
Ordinarily, the formatters indent text that follows an example as a new
paragraph.  You can prevent this on a case-by-case basis by writing
‘@noindent’ at the beginning of a line, preceding the continuation text.
You can also disable indentation for all paragraphs globally with
‘@paragraphindent’ (*note @paragraphindent::).

   Here is an example showing how to eliminate the normal indentation of
the text after an ‘@example’, a common situation:

     @example
     This is an example
     @end example

     @noindent
     This line is not indented.  As you can see, the
     beginning of the line is fully flush left with the
     line that follows after it.

produces:

          This is an example

     This line is not indented.  As you can see, the
     beginning of the line is fully flush left with the
     line that follows after it.

   The standard usage of ‘@noindent’ is just as above: at the beginning
of what would otherwise be a paragraph, to eliminate the indentation
that normally happens there.  It can either be followed by text or be on
a line by itself.  There is no reason to use it in other contexts, such
as in the middle of a paragraph or inside an environment (*note
Quotations and Examples::).

   You can control the number of blank lines in the Info file output by
adjusting the input as desired: a line containing just ‘@noindent’ does
not generate a blank line, and neither does an ‘@end’ line for an
environment.

   Do not put braces after a ‘@noindent’ command; they are not used,
since ‘@noindent’ is a command used outside of paragraphs (*note Command
Syntax::).


File: texinfo.info,  Node: @indent,  Next: @cartouche,  Prev: @noindent,  Up: Quotations and Examples

7.13 ‘@indent’: Forcing Indentation
===================================

   To complement the ‘@noindent’ command (see the previous section),
Texinfo provides the ‘@indent’ command to force a paragraph to be
indented.  For instance, this paragraph (the first in this section) is
indented using an ‘@indent’ command.

   And indeed, the first paragraph of a section is the most likely place
to use ‘@indent’, to override the normal behavior of no indentation
there (*note @paragraphindent::).  It can either be followed by text or
be on a line by itself.

   As a special case, when ‘@indent’ is used in an environment where
text is not filled, it produces a paragraph indentation space in the TeX
output.  (These environments are where a line of input produces a line
of output, such as ‘@example’ and ‘@display’; for a summary of all
environments, *note Block Enclosing Commands::.)

   Do not put braces after an ‘@indent’ command; they are not used,
since ‘@indent’ is a command used outside of paragraphs (*note Command
Syntax::).


File: texinfo.info,  Node: @cartouche,  Next: small,  Prev: @indent,  Up: Quotations and Examples

7.14 ‘@cartouche’: Rounded Rectangles
=====================================

Where the output format allows, the ‘@cartouche’ command draws a box
with rounded corners around its contents.  You can use this command to
isolate a portion of the manual from the main flow.  You can also
further highlight an example or quotation with ‘@cartouche’.

   For instance, you could write a manual in which one type of example
is surrounded by a cartouche for emphasis.  For example,

     @cartouche
     @example
     % pwd
     /usr/local/share/emacs
     @end example
     @end cartouche

surrounds the two-line example with a box with rounded corners, in the
printed manual.

   The output from the example looks like this (if you're reading this
in Info, you'll see the ‘@cartouche’ had no effect):

     % pwd
     /usr/local/share/emacs

   ‘@cartouche’ takes one optional argument, given on the remainder of
the line.  This text, if present, is the cartouche title.  It is output
in bold or otherwise emphasized at the beginning of the cartouche, and
is centered in some output formats.

   The following example illustrates a cartouche with a title:

     @cartouche Important
     Text explaining something important out of the main
     flow of the text.
     @end cartouche

   The cartouche with a title looks like this:

                               Important
   Text explaining something important out of the main flow of the text.

   A cartouche is output on a single page in printed output, similarly
to ‘@group’ (*note @group::).


File: texinfo.info,  Node: small,  Prev: @cartouche,  Up: Quotations and Examples

7.15 ‘@small...’ Block Commands
===============================

In addition to the regular ‘@example’ and similar commands, Texinfo has
"small" example-style commands.  These are ‘@smallquotation’,
‘@smallindentedblock’, ‘@smalldisplay’, ‘@smallexample’, ‘@smallformat’,
and ‘@smalllisp’.

   In most output formats, the ‘@small...’ commands are equivalent to
their non-small companion commands.

   In printed output, however, the ‘@small...’ commands typeset text in
a smaller font than the non-small example commands.  Thus, for instance,
code examples can contain longer lines and still fit on a page without
needing to be rewritten.

   Mark the end of a ‘@small...’ block with a corresponding ‘@end
small...’.  For example, pair ‘@smallexample’ with ‘@end smallexample’.

   Here is an example of the font used by the ‘@smallexample’ command
(in most output formats, the output will be the same as usual):

     ... to make sure that you have the freedom to
     distribute copies of free software (and charge for
     this service if you wish), that you receive source
     code or can get it if you want it, that you can
     change the software or use pieces of it in new free
     programs; and that you know you can do these things.

   The ‘@small...’ commands use the same font style as their normal
counterparts: ‘@smallexample’ and ‘@smalllisp’ use a fixed-width font,
and everything else uses the regular font.  They also have the same
behavior in other respects--whether filling is done and whether margins
are narrowed.  They do not take arguments even when their normal
counterparts do, however.

   As a general rule, it's better to just use the regular commands (such
as ‘@example’ instead of ‘@smallexample’), unless you have a good reason
for it.  When processing with ‘texinfo.tex’ only, you can obtain a
similar effect with ‘@set dispenvsize small’, which uses a smaller font
for ‘@example’ and other environments.  In HTML output, you can use CSS
to change the font size of enviroments if needed; *note HTML CSS::.


File: texinfo.info,  Node: Lists and Tables,  Next: Special Displays,  Prev: Quotations and Examples,  Up: Top

8 Lists and Tables
******************

Texinfo has several ways of making lists and tables.  Lists can be
bulleted or numbered; two-column tables can highlight the items in the
first column; multi-column tables are also supported.

* Menu:

* Introducing Lists::          Texinfo formats lists for you.
* @itemize::                   How to construct a simple list.
* @enumerate::                 How to construct a numbered list.
* Two-column Tables::          How to construct a two-column table.
* Multi-column Tables::        How to construct generalized tables.


File: texinfo.info,  Node: Introducing Lists,  Next: @itemize,  Up: Lists and Tables

8.1 Introducing Lists
=====================

Texinfo automatically indents the text in lists or tables, and numbers
an enumerated list.  This last feature is useful if you modify the list,
since you do not need to renumber it yourself.

   Numbered lists and tables begin with the appropriate @-command at the
beginning of a line, and end with the corresponding ‘@end’ command on a
line by itself.  The table and itemized-list commands also require that
you write formatting information on the same line as the beginning
@-command.

   Begin an enumerated list, for example, with an ‘@enumerate’ command
and end the list with an ‘@end enumerate’ command.  Begin an itemized
list with an ‘@itemize’ command, followed on the same line by a
formatting command such as ‘@bullet’, and end the list with an ‘@end
itemize’ command.

   Precede each element of a list with an ‘@item’ or ‘@itemx’ command.


Here is an itemized list of the different kinds of table and lists:

   • Itemized lists with and without bullets.

   • Enumerated lists, using numbers or letters.

   • Two-column tables with highlighting.


Here is an enumerated list with the same items:

  1. Itemized lists with and without bullets.

  2. Enumerated lists, using numbers or letters.

  3. Two-column tables with highlighting.


And here is a two-column table with the same items and their @-commands:

‘@itemize’
     Itemized lists with and without bullets.

‘@enumerate’
     Enumerated lists, using numbers or letters.

‘@table’
‘@ftable’
‘@vtable’
     Two-column tables, optionally with indexing.


File: texinfo.info,  Node: @itemize,  Next: @enumerate,  Prev: Introducing Lists,  Up: Lists and Tables

8.2 ‘@itemize’: Making an Itemized List
=======================================

The ‘@itemize’ command produces a sequence of "items", each starting
with a bullet or other mark inside the left margin, and generally
indented.

   Begin an itemized list by writing ‘@itemize’ at the beginning of a
line.  Follow the command, on the same line, with a Texinfo command or
character to generate a mark.  Usually, you will use ‘@bullet’ after
‘@itemize’, but you can use ‘@minus’, or any other Texinfo command or
character.  If you don't specify a mark command, the default is
‘@bullet’.

   After the ‘@itemize’, write your items, each starting with ‘@item’.
Text can follow on the same line as the ‘@item’.  The text of an item
can continue for more than one paragraph.

   Here is an example of the use of ‘@itemize’:

     @itemize @bullet{}
     @item
     Some text for foo.

     @item
     Some text
     for bar.
     @end itemize

This produces:

        • Some text for foo.

        • Some text for bar.

   When you give a mark command such as ‘@bullet’ as the argument to
‘@itemize’ command, you may omit the ‘{}’ that would normally follow the
command.

   If you don't want any mark at all, but still want logical items, use
‘@w{}’ (in this case the braces are required).

   There should be at least one ‘@item’ inside the ‘@itemize’
environment.  If none are present, ‘texi2any’ gives a warning.  If you
just want indented text and not a list of items, use ‘@indentedblock’;
*note @indentedblock::.

   Index entries that occur immediately before an ‘@item’ are associated
with the ‘@item’.

   Usually, you should put a blank line between items.  This puts a
blank line in the Info file.  (TeX inserts the proper vertical space in
any case.)  Except when the entries are very brief, these blank lines
make the list look better.

   Itemized lists may be embedded within other itemized lists.  Here is
a list marked with dashes embedded in a list marked with bullets:

     @itemize @bullet{}
     @item
     First item.

     @itemize @minus{}
     @item
     Inner item.

     @item
     Second inner item.
     @end itemize

     @item
     Second outer item.
     @end itemize

This produces:

        • First item.

             − Inner item.

             − Second inner item.

        • Second outer item.


File: texinfo.info,  Node: @enumerate,  Next: Two-column Tables,  Prev: @itemize,  Up: Lists and Tables

8.3 ‘@enumerate’: Making a Numbered or Lettered List
====================================================

‘@enumerate’ is like ‘@itemize’ (*note @itemize::), except that the
labels on the items are successive integers or letters instead of
bullets.

   Write the ‘@enumerate’ command at the beginning of a line.  The
command does not require an argument, but accepts either a number or a
letter as an option.  Without an argument, ‘@enumerate’ starts the list
with the number ‘1’.  With a numeric argument, such as ‘3’, the command
starts the list with that number.  With an upper- or lowercase letter,
such as ‘a’ or ‘A’, the command starts the list with that letter.

   Write the text of the enumerated list in the same way as an itemized
list: write a line starting with ‘@item’ at the beginning of each item
in the enumeration.  It is ok to have text following the ‘@item’, and
the text for an item can continue for several paragraphs.

   You should put a blank line between entries in the list.  This
generally makes it easier to read the Info file.

   Here is an example of ‘@enumerate’ without an argument:

     @enumerate
     @item
     Underlying causes.

     @item
     Proximate causes.
     @end enumerate

This produces:

  1. Underlying causes.

  2. Proximate causes.

   Here is an example with an argument of ‘3’:

     @enumerate 3
     @item
     Predisposing causes.

     @item
     Precipitating causes.

     @item
     Perpetuating causes.
     @end enumerate

This produces:

  3. Predisposing causes.

  4. Precipitating causes.

  5. Perpetuating causes.

   Here is a summary:

  a. ‘@enumerate’

     Without an argument, produce a numbered list, with the first item
     numbered 1.

  b. ‘@enumerate UNSIGNED-INTEGER’

     With an (unsigned) numeric argument, start a numbered list with
     that number.  You can use this to continue a list that you
     interrupted with other text.

  c. ‘@enumerate UPPER-CASE-LETTER’

     With an uppercase letter as argument, start a list in which each
     item is marked by a letter, beginning with that uppercase letter.

  d. ‘@enumerate LOWER-CASE-LETTER’

     With a lowercase letter as argument, start a list in which each
     item is marked by a letter, beginning with that lowercase letter.

   You can also nest enumerated lists, as in an outline.


File: texinfo.info,  Node: Two-column Tables,  Next: Multi-column Tables,  Prev: @enumerate,  Up: Lists and Tables

8.4 Making a Two-column Table
=============================

‘@table’ is similar to ‘@itemize’ (*note @itemize::), but allows you to
specify a name or heading line for each item.  The ‘@table’ command is
used to produce two-column tables, and is especially useful for
glossaries, explanatory exhibits, and command-line option summaries.

* Menu:

* @table::                     How to construct a two-column table.
* @ftable @vtable::            Automatic indexing for two-column tables.
* @itemx::                     How to put more entries in the first column.


File: texinfo.info,  Node: @table,  Next: @ftable @vtable,  Up: Two-column Tables

8.4.1 Using the ‘@table’ Command
--------------------------------

Use the ‘@table’ command to produce a two-column table.  This command is
typically used when you have a list of items and a brief text with each
one, such as a list of definitions.

   Write the ‘@table’ command at the beginning of a line, after a blank
line, and follow it on the same line with an argument that is an
'indicating' command, such as ‘@code’, ‘@samp’, ‘@var’, ‘@option’, or
‘@kbd’ (*note Indicating::).  This command will be applied to the text
in the first column.  For example, ‘@table @code’ will cause the text in
the first column to be output as if it had been the argument to a
‘@code’ command.

   You may use the ‘@asis’ command as an argument to ‘@table’.  ‘@asis’
is a command that does nothing: if you use this command after ‘@table’,
the first column entries are output without added highlighting ("as
is").

   The ‘@table’ command works with other commands besides those
explicitly mentioned here.  However, you can only use predefined Texinfo
commands that take an argument in braces.  You cannot reliably use a new
command defined with ‘@macro’, although an ‘@alias’ (for a suitable
predefined command) is acceptable.  *Note Defining New Texinfo
Commands::.

   Begin each table entry with an ‘@item’ command at the beginning of a
line.  Write the text for the first column on the same line as the
‘@item’ command.  Write the text for the second column on the line
following the ‘@item’ line and on subsequent lines.  You may write as
many lines of supporting text as you wish, even several paragraphs.  But
only the text on the same line as the ‘@item’ will be placed in the
first column (including any footnotes).  You do not need to type
anything for an empty second column.

   Normally, you should put a blank line between table entries.  This
puts a blank line in the Info file, which looks better unless the
entries are very brief.

   End the table with a line consisting of ‘@end table’.  Follow the end
of the table by a blank line for consistent formatting across output
formats.

   For example, the following table highlights the text in the first
column with the ‘@samp’ command:

     @table @samp
     @item foo
     This is the text for
     @samp{foo}.

     @item bar
     Text for @samp{bar}.
     @end table

This produces:

‘foo’
     This is the text for ‘foo’.
‘bar’
     Text for ‘bar’.

   If you want to list two or more named items with a single block of
text, use the ‘@itemx’ command.  (*Note @itemx::.)

   The ‘@table’ command (*note @table::) is not supported inside
‘@display’.  Since ‘@display’ is line-oriented, it doesn't make sense to
use them together.  If you want to indent a table, try ‘@quotation’
(*note @quotation::) or ‘@indentedblock’ (*note @indentedblock::).


File: texinfo.info,  Node: @ftable @vtable,  Next: @itemx,  Prev: @table,  Up: Two-column Tables

8.4.2 ‘@ftable’ and ‘@vtable’
-----------------------------

The ‘@ftable’ and ‘@vtable’ commands are the same as the ‘@table’
command except that ‘@ftable’ automatically enters each of the items in
the first column of the table into the index of functions and ‘@vtable’
automatically enters each of the items in the first column of the table
into the index of variables.  This simplifies the task of creating
indices.  Only the items on the same line as the ‘@item’ or ‘@itemx’
commands are indexed, and they are indexed in exactly the form that they
appear on that line.  *Note Indices::, for more information about
indices.

   Begin a two-column table using ‘@ftable’ or ‘@vtable’ by writing the
@-command at the beginning of a line, followed on the same line by an
argument that is a Texinfo command such as ‘@code’, exactly as you would
for a ‘@table’ command; and end the table with an ‘@end ftable’ or ‘@end
vtable’ command on a line by itself.

   See the example for ‘@table’ in the previous section.


File: texinfo.info,  Node: @itemx,  Prev: @ftable @vtable,  Up: Two-column Tables

8.4.3 ‘@itemx’: Second and Subsequent Items
-------------------------------------------

Use the ‘@itemx’ command inside a table when you have two or more first
column entries for the same item, each of which should appear on a line
of its own.

   Use ‘@item’ for the first entry, and ‘@itemx’ for all subsequent
entries; ‘@itemx’ must always follow an ‘@item’ command, with no blank
line intervening.

   The ‘@itemx’ command works exactly like ‘@item’ except that it does
not generate extra vertical space above the first column text in some
output formats.  If you have multiple consecutive ‘@itemx’ commands, do
not insert any blank lines between them.

   For example,

     @table @code
     @item upcase
     @itemx downcase
     These two functions accept a character or a string as
     argument, and return the corresponding uppercase (lowercase)
     character or string.
     @end table

This produces:

‘upcase’
‘downcase’
     These two functions accept a character or a string as argument, and
     return the corresponding uppercase (lowercase) character or string.

(Note also that this example illustrates multi-line supporting text in a
two-column table.)


File: texinfo.info,  Node: Multi-column Tables,  Prev: Two-column Tables,  Up: Lists and Tables

8.5 ‘@multitable’: Multi-column Tables
======================================

‘@multitable’ allows you to construct tables with any number of columns,
with each column having any width you like.

   You define the column widths on the ‘@multitable’ line itself, and
write each row of the actual table following an ‘@item’ command, with
columns separated by a ‘@tab’ command.  Finally, ‘@end multitable’
completes the table.  Details in the sections below.

* Menu:

* Multitable Column Widths::   Defining multitable column widths.
* Multitable Rows::            Defining multitable rows, with examples.


File: texinfo.info,  Node: Multitable Column Widths,  Next: Multitable Rows,  Up: Multi-column Tables

8.5.1 Multitable Column Widths
------------------------------

You can define the column widths for a multitable in two ways: as
fractions of the line length; or with a prototype row.  Mixing the two
methods is not supported.  In either case, the widths are defined
entirely on the same line as the ‘@multitable’ command.

  1. To specify column widths as fractions of the line length, write
     ‘@columnfractions’ and the decimal numbers (presumably less than 1;
     a leading zero is allowed and ignored) after the ‘@multitable’
     command, as in:

          @multitable @columnfractions .33 .33 .33

     The fractions need not add up exactly to 1.0, as these do not.
     This allows you to produce tables that do not need the full line
     length.

     When using ‘@columnfractions’, the leftmost column may appear
     slightly wider than you might expect, relative to the other
     columns.  This is due to spacing between columns being included in
     the width of the other columns.

  2. To specify a prototype row, write the longest entry for each column
     enclosed in braces after the ‘@multitable’ command.  For example:

          @multitable {some text for column one} {for column two}

     The first column will then have the width of the typeset 'some text
     for column one', and the second column the width of 'for column
     two'.

     The prototype entries need not appear in the table itself.

     Although we used simple text in this example, the prototype entries
     can contain Texinfo commands; markup commands such as ‘@code’ are
     particularly likely to be useful.

     Prototype rows have no effect in HTML output.


File: texinfo.info,  Node: Multitable Rows,  Prev: Multitable Column Widths,  Up: Multi-column Tables

8.5.2 Multitable Rows
---------------------

After the ‘@multitable’ command defining the column widths (see the
previous section), you begin each row in the body of a multitable with
‘@item’, and separate the column entries with ‘@tab’.  Line breaks are
not special within the table body, and you may break input lines in your
source file as necessary.

   You can also use ‘@headitem’ instead of ‘@item’ to produce a “heading
row”.  The TeX output for such a row is in bold, and the HTML and
DocBook output uses the ‘<thead>’ tag.  In Info, the heading row is
followed by a separator line made of dashes (‘-’ characters).

   The command ‘@headitemfont’ can be used in templates when the entries
in a ‘@headitem’ row need to be used in a template.  It is a synonym for
‘@b’, but using ‘@headitemfont’ avoids any dependency on that particular
font style, in case we provide a way to change it in the future.

   Here is a complete example of a multi-column table (the text is from
‘The GNU Emacs Manual’, *note Splitting Windows: (emacs)Split Window.):

     @multitable @columnfractions .15 .45 .4
     @headitem Key @tab Command @tab Description
     @item C-x 2
     @tab @code{split-window-vertically}
     @tab Split the selected window into two windows,
     with one above the other.
     @item C-x 3
     @tab @code{split-window-horizontally}
     @tab Split the selected window into two windows
     positioned side by side.
     @item C-Mouse-2
     @tab
     @tab In the mode line or scroll bar of a window,
     split that window.
     @end multitable

produces:

Key         Command                          Description
---------------------------------------------------------------------------
C-x 2       ‘split-window-vertically’        Split the selected window
                                             into two windows, with one
                                             above the other.
C-x 3       ‘split-window-horizontally’      Split the selected window
                                             into two windows positioned
                                             side by side.
C-Mouse-2                                    In the mode line or scroll
                                             bar of a window, split that
                                             window.


File: texinfo.info,  Node: Special Displays,  Next: Indices,  Prev: Lists and Tables,  Up: Top

9 Special Displays
******************

The commands in this chapter allow you to write text that is specially
displayed (output format permitting), outside of the normal document
flow.

   One set of such commands is for creating "floats", that is, figures,
tables, and the like, set off from the main text, possibly numbered,
captioned, and/or referred to from elsewhere in the document.  Images
are often included in these displays.

   Another group of commands is for creating footnotes in Texinfo.

* Menu:

* Floats::                     Figures, tables, and the like.
* Images::                     Including graphics and images.
* Footnotes::                  Writing footnotes.


File: texinfo.info,  Node: Floats,  Next: Images,  Up: Special Displays

9.1 Floats
==========

A “float” is a display which is set off from the main text.  It is
typically labeled as being a "Figure", "Table", "Example", or some
similar type.

   A float is so-named because, in principle, it can be moved to the
bottom or top of the current page, or to a following page, in the
printed output.  (Floating does not make sense in other output formats.)
In every output format except for LaTeX, however, this floating is
unfortunately not yet implemented.  Instead, the floating material is
simply output at the current location, more or less as if it were an
‘@group’ (*note @group::).

* Menu:

* @float::                     Producing floating material.
* @caption @shortcaption::     Specifying descriptions for floats.
* @listoffloats::              A table of contents for floats.


File: texinfo.info,  Node: @float,  Next: @caption @shortcaption,  Up: Floats

9.1.1 ‘@float’ [TYPE][,LABEL]: Floating Material
------------------------------------------------

To produce floating material, enclose the material you want to be
displayed separate between ‘@float’ and ‘@end float’ commands, on lines
by themselves.

   Floating material often uses ‘@image’ to display an already-existing
graphic (*note Images::), or ‘@multitable’ to display a table (*note
Multi-column Tables::).  However, the contents of the float can be
anything.  Here's an example with simple text:

     @float Figure,fig:ex1
     This is an example float.
     @end float

And the output:

This is an example float.

Figure 9.1
   As shown in the example, ‘@float’ takes two arguments (separated by a
comma), TYPE and LABEL.  Both are optional.

TYPE
     Specifies the sort of float this is; typically a word such as
     "Figure", "Table", etc.  If this is not given, and LABEL is, any
     cross-referencing will simply use a bare number.

LABEL
     Specifies a cross-reference label for this float.  If given, this
     float is automatically given a number, and will appear in any
     ‘@listoffloats’ output (*note @listoffloats::).  Cross references
     to LABEL are allowed.  For example, ‘see @ref{fig:ex1}’ will
     produce see *note Figure 9.1: fig:ex1.

     On the other hand, if LABEL is not given, then the float will not
     be numbered and consequently will not appear in the ‘@listoffloats’
     output or be cross-referenceable.

Ordinarily, you specify both TYPE and LABEL, to get a labeled and
numbered float.

   In the LaTeX output, code loading the ‘float’ package is output in
the preamble if ‘@float’ are present.  A ‘@float’ with type ‘figure’ or
‘table’ (case insensitive) is already defined by the package.  Other
float types lead to the definition of a new float environment, with
names based on the ‘@float’ type with anything else than letters and ‘-’
removed.

   In Texinfo, all floats are numbered in the same way: with the chapter
number (or appendix letter), a period, and the float number, which
simply counts 1, 2, 3, ..., and is reset at each chapter.  Each float
type is counted independently.

   Floats within an ‘@unnumbered’, or outside of any chapter, are simply
numbered consecutively from 1.

   These numbering conventions are not, at present, changeable.


File: texinfo.info,  Node: @caption @shortcaption,  Next: @listoffloats,  Prev: @float,  Up: Floats

9.1.2 ‘@caption’ & ‘@shortcaption’
----------------------------------

You may write a ‘@caption’ anywhere within a ‘@float’ environment, to
define a caption for the float.  It is not allowed in any other context.
‘@caption’ takes a single argument, enclosed in braces.  Here's an
example:

     @float
     An example float, with caption.
     @caption{Caption for example float.}
     @end float

The output is:

An example float, with caption.

Caption for example float.

   ‘@caption’ can appear anywhere within the float; it is not processed
until the ‘@end float’.  The caption text is usually a sentence or two,
but may consist of several paragraphs if necessary.

   In the output, the caption always appears below the float; this is
not currently changeable.  It is preceded by the float type and/or
number, as specified to the ‘@float’ command (see the previous section).

   The ‘@shortcaption’ command likewise may be used only within
‘@float’, and takes a single argument in braces.  The short caption text
is used instead of the caption text in a list of floats (see the next
section).  Thus, you can write a long caption for the main document, and
a short title to appear in the list of floats.  For example:

     @float
     ... as above ...
     @shortcaption{Text for list of floats.}
     @end float

   The text for ‘@shortcaption’ may not contain comments (‘@c’),
verbatim text (‘@verb’), environments such as ‘@example’, footnotes
(‘@footnote’), multiple paragraphs, or other complex constructs.  The
same constraints apply to ‘@caption’ unless there is a ‘@shortcaption’.
In LaTeX a multi-paragraph ‘@caption’ will lead to an error when
formatted, unless there is a ‘@shortcaption’.


File: texinfo.info,  Node: @listoffloats,  Prev: @caption @shortcaption,  Up: Floats

9.1.3 ‘@listoffloats’: Tables of Contents for Floats
----------------------------------------------------

You can write a ‘@listoffloats’ command to generate a list of floats for
a given float type (*note @float::), analogous to the document's overall
table of contents.  Typically, it is written in its own ‘@unnumbered’
node to provide a heading and structure, rather like ‘@printindex’
(*note Printing Indices & Menus::).

   ‘@listoffloats’ takes one optional argument, the float type.  Here's
an example:

     @node List of Figures
     @unnumbered List of Figures
     @listoffloats Figure

Without any argument, ‘@listoffloats’ generates a list of floats for
which no float type was specified, i.e., no first argument to the
‘@float’ command (*note @float::).

   Here's what the output from ‘@listoffloats’ looks like, given the
example figure earlier in this chapter:

     *      Figure 12.1:      fig:ex1.

   Usually, each line in the list of floats contains the float type (if
any), the float number, and the caption, if any--the ‘@shortcaption’
argument, if it was specified, else the ‘@caption’ argument.  The page
number may also be included, depending on output format.

   Unnumbered floats (those without cross-reference labels) are omitted
from the list of floats.

   The formatting of ‘@listoffloats’ depends on the output format.  In
Info, for example, a ‘@listoffloats’ is formatted as a menu.

   In LaTeX output, ‘\listoffigures’ is output for the ‘figure’ (case
insensitive) float type, ‘\listoftables’ is output for the ‘table’ (case
insensitive) float type.  For other float types, a specific ‘\listof’
command is output.


File: texinfo.info,  Node: Images,  Next: Footnotes,  Prev: Floats,  Up: Special Displays

9.2 Inserting Images
====================

You can insert an image given in an external file with the ‘@image’
command.  Although images can be used anywhere, including the middle of
a paragraph, we describe them in this chapter since they are most often
part of a displayed figure or example.

* Menu:

* Image Syntax::
* Image Scaling::


File: texinfo.info,  Node: Image Syntax,  Next: Image Scaling,  Up: Images

9.2.1 Image Syntax
------------------

Here is the synopsis of the ‘@image’ command:

     @image{FILENAME[, WIDTH[, HEIGHT[, ALTTEXT[, EXTENSION]]]]}

   The FILENAME argument is mandatory, and must not have an extension,
because the different processors support different formats:

   • TeX (DVI output) reads the file ‘FILENAME.eps’ (Encapsulated
     PostScript format).

   • TeX (PDF output) reads ‘FILENAME.pdf’, ‘FILENAME.png’,
     ‘FILENAME.jpg’, or ‘FILENAME.jpeg’ (in that order).  It also tries
     uppercase versions of the extensions.  The PDF format does not
     support EPS images, so such must be converted first.

   • In Info, ‘FILENAME.txt’ is included verbatim (more or less as if it
     were in ‘@verbatim’).  The Info output may also include a reference
     to ‘FILENAME.png’ or ‘FILENAME.jpg’.  (See below.)

   • In HTML, a reference to ‘FILENAME.png’, ‘FILENAME.jpg’,
     ‘FILENAME.jpeg’ or ‘FILENAME.gif’ (in that order) is output.  If
     none of those exist, it gives an error, and outputs a reference to
     ‘FILENAME.jpg’ anyway.

   • In DocBook, references to ‘FILENAME.eps’, ‘FILENAME.gif’,
     ‘FILENAME.jpeg’, ‘FILENAME.jpg’, ‘FILENAME.pdf’, ‘FILENAME.png’ and
     ‘FILENAME.svg’ are output, for every file found.  Also,
     ‘FILENAME.txt’ is included verbatim, if present.  (The subsequent
     DocBook processor is supposed to choose the appropriate one.)

   • For LaTeX, ‘FILENAME’ without any extension is used; the subsequent
     LaTeX processor is supposed to choose the appropriate image type.

   • For Info and HTML output, the optional fifth argument EXTENSION to
     ‘@image’ is used for the file extension, if it is specified and the
     file is found.  Any leading period should be included in EXTENSION.
     For example:

          @image{foo,,,,.xpm}

   If you want to install image files for use by Info readers too, we
recommend putting them in a subdirectory like ‘FOO-figures’ for a
package FOO.  Copying the files into ‘$(infodir)/FOO-figures/’ should be
done in your ‘Makefile’.

   The WIDTH and HEIGHT arguments are described in the next section.

   If an image is the first thing in a paragraph and followed by more
text, then you should precede the ‘@image’ command with ‘@indent’ or
‘@noindent’ to indicate the beginning of paragraph formatting.  This is
especially important for TeX output to get correct paragraph
indentation.

   Use ‘@center’ to center an image (*note @titlefont @center @sp::).

   For HTML output, the “alt attribute” for inline images is set to the
optional ALTTEXT (fourth) argument to ‘@image’, if supplied.  If not
supplied, the full file name of the image being displayed is used.  The
ALTTEXT is processed as Texinfo text, so special characters such as ‘"’
and ‘<’ and ‘&’ are escaped in the HTML output; also, you can get an
empty ‘alt’ string with ‘@-’ (a command that produces no output; *note
@- @hyphenation::).

   For Info output, the ALTTEXT string is also processed as Texinfo text
and output.  In this case, ‘\’ is escaped as ‘\\’ and ‘"’ as ‘\"’; no
other escapes are done.

   In Info output, a reference to the binary image file is written
(trying FILENAME suffixed with ‘EXTENSION’, ‘.EXTENSION’, ‘.png’, or
‘.jpg’, in that order) if one exists.  The ‘.txt’ file is also literally
included, if one exists.  This way, Info readers which can display
images (such as the Emacs Info browser, running under X) can do so,
whereas Info readers which can only use text (such as the standalone
Info reader) can display the textual version.


File: texinfo.info,  Node: Image Scaling,  Prev: Image Syntax,  Up: Images

9.2.2 Image Scaling
-------------------

The optional WIDTH and HEIGHT arguments to the ‘@image’ command (see the
previous section) specify the size to which to scale the image.  They
are only taken into account in printed output.

   In TeX, if neither is specified, the image is presented in its
natural size (given in the file); if only one is specified, the other is
scaled proportionately; and if both are specified, both are respected,
thus likely distorting the original image by changing its aspect ratio.

   The WIDTH and HEIGHT may be specified using any valid TeX dimension,
namely:

pt
     point (72.27pt = 1in)
pc
     pica (1pc = 12pt)
bp
     big point (72bp = 1in)
in
     inch
cm
     centimeter (2.54cm = 1in)
mm
     millimeter (10mm = 1cm)
dd
     didôt point (1157dd = 1238pt)
cc
     cicero (1cc = 12dd)
sp
     scaled point (65536sp = 1pt)

   For example, the following will scale a file ‘ridt.eps’ to one inch
vertically, with the width scaled proportionately:

     @image{ridt,,1in}

   For ‘@image’ to work with TeX, the file ‘epsf.tex’ must be installed
somewhere that TeX can find it.  (The standard location is
‘TEXMF/tex/generic/dvips/epsf.tex’, where TEXMF is a root of your TeX
directory tree.)  This file is included in the Texinfo distribution and
is also available from <ftp://tug.org/tex/epsf.tex>, among other places.

   ‘@image’ can be used within a line as well as for displayed figures.
Therefore, if you intend it to be displayed, be sure to leave a blank
line before the command, or the output will run into the preceding text.

   Image scaling is presently implemented only in printed output, not in
any other sort of output.


File: texinfo.info,  Node: Footnotes,  Prev: Images,  Up: Special Displays

9.3 Footnotes
=============

A “footnote” is for a reference that documents or elucidates the primary
text.(1)

   Footnotes are distracting; use them sparingly at most, and it is best
to avoid them completely.  Standard bibliographical references are
usually better placed in a bibliography at the end of a document instead
of in footnotes throughout.

* Menu:

* Footnote Commands::          How to write a footnote in Texinfo.
* Footnote Styles::            Controlling how footnotes appear.

   ---------- Footnotes ----------

   (1) A footnote should complement or expand upon the primary text, but
a reader should not need to read a footnote to understand the primary
text.  For a thorough discussion of footnotes, see ‘The Chicago Manual
of Style’, which is published by the University of Chicago Press.


File: texinfo.info,  Node: Footnote Commands,  Next: Footnote Styles,  Up: Footnotes

9.3.1 Footnote Commands
-----------------------

In Texinfo, footnotes are created with the ‘@footnote’ command.  This
command is followed immediately by a left brace, then by the text of the
footnote, and then by a terminating right brace.  Footnotes may be of
any length (they will be broken across pages if necessary), but are
usually short.  The template is:

     ordinary text@footnote{TEXT OF FOOTNOTE}

   As shown here, the ‘@footnote’ command should come right after the
text being footnoted, with no intervening space; otherwise, the footnote
marker might end up starting a line.

   For example, this clause is followed by a sample footnote(1); in the
Texinfo source, it looks like this:

     ...a sample footnote@footnote{Here is the sample
     footnote.}; in the Texinfo source...

   As you can see, this source includes two punctuation marks next to
each other; in this case, ‘.};’ is the sequence.  This is normal (the
first ends the footnote and the second belongs to the sentence being
footnoted), so don't worry that it looks odd.  (Another style, perfectly
acceptable, is to put the footnote after punctuation belonging to the
sentence, as in ‘;@footnote{...’.)

   In printed output formats, the reference mark for a footnote is a
small, superscripted number; the text of the footnote appears at the
bottom of the page, below a horizontal line.

   In Info, the reference mark for a footnote is a pair of parentheses
with the footnote number between them, like this: ‘(1)’.  The reference
mark is followed by a cross-reference link to the footnote text if
footnotes are put in separate nodes (*note Footnote Styles::).

   In the HTML output, footnote references are generally marked with a
small, superscripted number which is rendered as a hypertext link to the
footnote text.

   Footnotes cannot be nested, and cannot appear in section headings of
any kind or other "unusual" places.

   A final tip: footnotes in the argument of an ‘@item’ command for an
‘@table’ must be entirely on the same line as the ‘@item’ (as usual).
*Note Two-column Tables::.

   ---------- Footnotes ----------

   (1) Here is the sample footnote.


File: texinfo.info,  Node: Footnote Styles,  Prev: Footnote Commands,  Up: Footnotes

9.3.2 Footnote Styles
---------------------

Online formats have two footnote styles, which determine where the text
of the footnote is located, the ‘end’ and ‘separate’ footnote style.

‘end’
     For Info, in the ‘end’ node style, all the footnotes for a single
     node are placed at the end of that node.  The footnotes are
     separated from the rest of the node by a line of dashes with the
     word ‘Footnotes’ within it.  Each footnote begins with an ‘(N)’
     reference mark.

     Here is an example of the Info output for a single footnote in the
     end-of-node style:

          --------- Footnotes ---------

          (1)  Here is a sample footnote.

     In HTML, when the footnote style is ‘end’, or if the output is not
     split, footnotes are put at the end of each output file.

‘separate’
     For Info, in the ‘separate’ node style, all the footnotes for a
     single node are placed in an automatically constructed node of
     their own.  In this style, a "footnote reference" follows each
     ‘(N)’ reference mark in the body of the node.  The footnote
     reference is actually a cross-reference which you use to reach the
     footnote node.

     The name of the node with the footnotes is constructed by appending
     ‘-Footnotes’ to the name of the node that contains the footnotes.
     (Consequently, the footnotes' node for the ‘Footnotes’ node is
     ‘Footnotes-Footnotes’!)  The footnotes' node has an 'Up' node
     pointer that leads back to its parent node.

     Here is how the first footnote in this manual looks after being
     formatted for Info in the separate node style:

          File: texinfo.info  Node: Overview-Footnotes, Up: Overview

          (1) The first syllable of "Texinfo" is pronounced like
          "speck", not "hex". ...

     In HTML, when the footnote style is ‘separate’, and the output is
     split, footnotes are placed in a separate file.

   Unless your document has long and important footnotes (as in, say,
Gibbon's ‘Decline and Fall ...’), we recommend the ‘end’ style, as it is
simpler for readers to follow.

   Use the ‘@footnotestyle’ command to specify the footnote style.
Write this command at the beginning of a line followed by an argument,
either ‘end’ for the end node style or ‘separate’ for the separate node
style.

   For example,

     @footnotestyle end
or
     @footnotestyle separate

   Write a ‘@footnotestyle’ command in the Texinfo file preamble.


File: texinfo.info,  Node: Indices,  Next: Insertions,  Prev: Special Displays,  Up: Top

10 Indices
**********

Using Texinfo, you can generate indices without having to sort and
collate entries manually.  In an index, the entries are listed in
alphabetical order, together with information on how to find the
discussion of each entry.  In a printed manual, this information
consists of page numbers.  In other formats, links to the index entries
location or to the associated nodes are generated.

   Texinfo provides several predefined kinds of indices: an index for
functions, an index for variables, an index for concepts, and so on.
You can combine indices or use them for other than their canonical
purpose.  Lastly, you can define your own new indices.

* Menu:

* Predefined Indices::         Use different indices for different kinds of
                               entries.
* Indexing Commands::          How to make an index entry.
* Advanced Indexing::          Advanced indexing commands.
* Index Entries::              Choose different words for index entries.
* Printing Indices & Menus::   How to print an index in hardcopy and generate
                               index menus in Info.
* Combining Indices::          How to combine indices.
* New Indices::                How to define your own indices.


File: texinfo.info,  Node: Predefined Indices,  Next: Indexing Commands,  Up: Indices

10.1 Predefined Indices
=======================

Texinfo provides six predefined indices.  Here are their nominal
meanings, abbreviations, and the corresponding index entry commands:

‘cp’
     (‘@cindex’) Concept index, for general concepts.
‘fn’
     (‘@findex’) Function index, for function and function-like names
     (such as entry points of libraries).
‘ky’
     (‘@kindex’) Keystroke index, for keyboard commands.
‘pg’
     (‘@pindex’) Program index, for names of programs.
‘tp’
     (‘@tindex’) Data type index, for type names (such as structures
     defined in header files).
‘vr’
     (‘@vindex’) Variable index, for variable names (such as library
     global variables).

Not every manual needs all of these, and most manuals use only two or
three at most.  The present manual, for example, has three indices: a
concept index, a variable index, and an @-command index.  (The last is
actually the function index but is called a command index in the chapter
heading.)

   You are not required to use the predefined indices strictly for their
canonical purposes.  For example, suppose you wish to index some C
preprocessor macros.  You could put them in the function index along
with actual functions, just by writing ‘@findex’ commands for them;
then, when you print the "Function Index" as an unnumbered chapter, you
could give it the title 'Function and Macro Index' and all will be
consistent for the reader.

   On the other hand, it is best not to stray too far from the meaning
of the predefined indices.  Otherwise, in the event that your text is
combined with other text from other manuals, the index entries will not
match up.  Instead, define your own new index (*note New Indices::).

   We recommend having a single index in the final document whenever
possible, however many source indices you use, since then readers have
only one place to look.  Two or more source indices can be combined into
one output index by using the ‘@synindex’ or ‘@syncodeindex’ commands
(*note Combining Indices::).

   Index entry commands based on the the two letter index names are also
valid, for example ‘@cpindex’ can be used instead of ‘@cindex’.


File: texinfo.info,  Node: Indexing Commands,  Next: Advanced Indexing,  Prev: Predefined Indices,  Up: Indices

10.2 Defining the Entries of an Index
=====================================

The data to make an index come from many individual indexing commands
scattered throughout the Texinfo source file.  Each command says to add
one entry to a particular index; after formatting, the index will give
the current page number or node name as the reference.

   An index entry consists of an indexing command at the beginning of a
line followed, on the rest of the line, by the entry.

   For example, this section begins with the following five entries for
the concept index:

     @cindex Defining indexing entries
     @cindex Index entries, defining
     @cindex Entries for an index
     @cindex Specifying index entries
     @cindex Creating index entries

   Each predefined index has its own indexing command--‘@cindex’ for the
concept index, ‘@findex’ for the function index, and so on, as listed in
the previous section.

   Index entries should precede the visible material that is being
indexed.  For instance:

     @cindex hello
     Hello, there!

Among other reasons, that way following indexing links (in whatever
context) ends up before the material, where readers want to be, instead
of after.

   In Info, an index is usually formatted as a menu.  Try to avoid using
a colon in index entries, as this may confuse some Info readers.  *Note
Menu Parts:: for more information about the structure of a menu entry.

   By default, entries for a concept index are printed in a roman font
and entries for the other indices are printed in a typewriter font.  You
may change the way part of an entry is printed with the usual Texinfo
commands, such as ‘@file’ for file names (*note Marking Text::), and
‘@r’ for the normal roman font (*note Fonts::).

   You may specify an explicit sort key for an index entry using
‘@sortas’ following either the index command or the text of the entry.
For example: ‘@findex @sortas{\} \ @r{(literal \ in @code{@@math})’
sorts the index entry this produces under backslash.

   You may choose to ignore certain characters in index entries for the
purposes of sorting.  The characters that you can currently choose to
ignore are ‘\’, ‘-’, ‘<’ and ‘@’, which are ignored by giving as an
argument to the ‘@set’ command, respectively, ‘txiindexbackslashignore’,
‘txiindexhyphenignore’, ‘txiindexlessthanignore’ and
‘txiindexatsignignore’.  For example, specifying ‘@set
txiindexbackslashignore’ causes the ‘\mathopsup’ entry in the index for
this manual to be sorted as if it were ‘mathopsup’, so that it appears
among the other entries beginning with 'M'. This avoids the need to
provide explicit sort keys for index entries containing these
characters.

   When using these options, it is possible to get an index entry with
an empty sort key.  To avoid this, specify a ‘@sortas’ directive in the
index entry.  For example:

     @set txiindexbackslashignore
     @findex @sortas{\} \


File: texinfo.info,  Node: Advanced Indexing,  Next: Index Entries,  Prev: Indexing Commands,  Up: Indices

10.3 Advanced Indexing Commands
===============================

Texinfo provides several further commands for indexing.

   First, you can create “multilevel” index entries, allowing you to
group many related subtopics under the same higher-level topic.  You do
this by separating the parts of such an entry with the ‘@subentry’
command.  Such commands might look like this:

     @cindex Superhumans @subentry villains
     @cindex Superhumans @subentry heroes

   You may have up to three levels in an entry:

     @cindex coffee makers @subentry electric @subentry pink
     @cindex coffee makers @subentry electric @subentry blue

   You can use the ‘@sortas’ command mentioned earlier with any or all
of the three parts of an entry to cause them to sort differently than
they would by default.

   Second, you may provide an index entry that points to another, using
the ‘@seeentry’ ("see entry") command.  For example:

     @cindex Indexes @seeentry{Indices}

   Such an entry should be unique in your document; the idea is to
redirect the reader to the other entry where they will find all the
information they are looking for.

   Finally, you may provide a "see also" entry using the ‘@seealso’
command.  These entries go along with regular entries, and are grouped
together with them in the final printed index.  For example:

     @cindex Coffee
     @cindex Coffee @subentry With milk and sugar
     @cindex Coffee @subentry With doughnuts
     @cindex Coffee @subentry Decaffeinated
     @cindex Coffee @seealso{Tea}

   When using all three of these advanced commands, _do not_ place a
comma between the different parts of the index text.  The ‘texindex’
program, which sorts the index entries and generates the indexing
formatting commands, takes care of placing commas in the correct places
for you.

   Do not interrupt an index or ‘@subentry’ entry by ‘@sortas’ or
advanced commands with braces; place the commands with braces at the
beginning or at the end of the entry.

   These features are the most useful with printed documents, and when
translating Texinfo to DocBook.


File: texinfo.info,  Node: Index Entries,  Next: Printing Indices & Menus,  Prev: Advanced Indexing,  Up: Indices

10.4 Making Index Entries
=========================

Concept index entries consist of text.  The best way to write an index
is to devise entries which are terse yet clear.  If you can do this, the
index usually looks better if the entries are written just as they would
appear in the middle of a sentence, that is, capitalizing only proper
names and acronyms that always call for uppercase letters.  This is the
case convention we use in most GNU manuals' indices.

   If you don't see how to make an entry terse yet clear, make it longer
and clear--not terse and confusing.  If many of the entries are several
words long, the index may look better if you use a different convention:
capitalize the first word of each entry.  Whichever case convention you
use, use it consistently.

   In any event, do not ever capitalize a case-sensitive name such as a
C or Lisp function name or a shell command; that would be a spelling
error.  Entries in indices other than the concept index are symbol names
in programming languages, or program names; these names are usually
case-sensitive, so likewise use upper- and lowercase as required.

   It is a good idea to make index entries unique wherever feasible.
That way, people using the printed output or online completion of index
entries don't see undifferentiated lists.  Consider this an opportunity
to make otherwise-identical index entries be more specific, so readers
can more easily find the exact place they are looking for.  The advanced
indexing features described in *note Advanced Indexing:: can help with
this, as well.

   When you are making index entries, it is good practice to think of
the different ways people may look for something.  Different people _do
not_ think of the same words when they look something up.  A helpful
index will have items indexed under all the different words that people
may use.  For example, one reader may think it obvious that the
two-letter names for indices should be listed under "Indices, two-letter
names", since "Indices" are the general concept.  But another reader may
remember the specific concept of two-letter names and search for the
entry listed as "Two letter names for indices".  A good index will have
both entries and will help both readers.

   Like typesetting, the construction of an index is a skilled art, the
subtleties of which may not be appreciated until you need to do it
yourself.


File: texinfo.info,  Node: Printing Indices & Menus,  Next: Combining Indices,  Prev: Index Entries,  Up: Indices

10.5 Printing Indices and Menus
===============================

‘@printindex’ takes one argument, a two-letter index abbreviation.  You
must include the ‘@printindex’ command at the place in the document
where you want the index to appear.  This does not happen automatically
just because you use ‘@cindex’ or other index-entry generating commands
in the Texinfo file; those just cause the raw data for the index to be
accumulated.

   You should precede the ‘@printindex’ command with a suitable section
or chapter command (usually ‘@appendix’ or ‘@unnumbered’) to supply the
chapter heading and put the index into the table of contents.  Precede
the chapter heading with an ‘@node’ line as usual.

   For example:

     @node Variable Index
     @unnumbered Variable Index

     @printindex vr

     @node Concept Index
     @unnumbered Concept Index

     @printindex cp

   The text ‘Index’ needs to appear in the name of the node containing
the index for the index to be found by Info readers.

   If you have more than one index, we recommend placing the concept
index last.

   Other details of index output in output formats:

   • As part of the process of creating a printed manual with TeX, you
     run a program called ‘texindex’ (*note Hardcopy with TeX::) to sort
     the raw data to produce a sorted index file.  The sorted index file
     is what is actually used to print the index.

     ‘@printindex’ reads the corresponding sorted index file and
     produces a traditional two-column index, with index terms and page
     numbers.

   • In Info output, ‘@printindex’ produces a special menu containing
     the line number of the entry, relative to the start of the node.
     Info readers can use this to go to the exact line of an entry, not
     just the containing node.  (Older Info readers will just go to the
     node.)  Here's an example:

          * First index entry:   Top.   (line  7)

   • In plain text output, ‘@printindex’ formatting is usually similar
     to a menu in Info, showing the line number of each entry relative
     to the start of the file.

   • In HTML output, ‘@printindex’ produces links to the index entries.

   • In DocBook and LaTeX output, it simply records the index to be
     printed.


File: texinfo.info,  Node: Combining Indices,  Next: New Indices,  Prev: Printing Indices & Menus,  Up: Indices

10.6 Combining Indices
======================

Sometimes you will want to combine two disparate indices such as
functions and concepts, perhaps because you have few enough entries that
a separate index would look silly.

   You could put functions into the concept index by writing ‘@cindex’
commands for them instead of ‘@findex’ commands, and produce a
consistent manual by printing the concept index with the title 'Function
and Concept Index' and not printing the 'Function Index' at all; but
this is not a robust procedure.  It works only if your document is never
included as part of another document that is designed to have a separate
function index; if your document were to be included with such a
document, the functions from your document and those from the other
would not end up together.  Also, to make your function names appear in
the right font in the concept index, you would need to enclose every one
of them between the braces of ‘@code’.

* Menu:

* @syncodeindex::              How to merge two indices, using ‘@code’ font for
                               the merged-from index.
* @synindex::                  How to merge two indices, using the roman font
                               for the merged-from index.


File: texinfo.info,  Node: @syncodeindex,  Next: @synindex,  Up: Combining Indices

10.6.1 ‘@syncodeindex’: Combining Indices Using ‘@code’
-------------------------------------------------------

When you want to combine functions and concepts into one index, you
should index the functions with ‘@findex’ and index the concepts with
‘@cindex’, and use the ‘@syncodeindex’ command to redirect the function
index entries into the concept index.

   The ‘@syncodeindex’ command takes two arguments; they are the name of
the index to redirect, and the name of the index to redirect it to.  The
template looks like this:

     @syncodeindex FROM TO

   For this purpose, the indices are given two-letter names:

‘cp’
     Concept index
‘fn’
     Function index
‘ky’
     Key index
‘pg’
     Program index
‘tp’
     Data type index
‘vr’
     Variable index

   Write a ‘@syncodeindex’ command before or shortly after the
end-of-header line at the beginning of a Texinfo file.  For example, to
merge a function index with a concept index, write the following:

     @syncodeindex fn cp

This causes all entries designated for the function index to merge in
with the concept index instead.

   To merge both a variable index and a function index into a concept
index, write the following:

     @syncodeindex vr cp
     @syncodeindex fn cp

   The ‘@syncodeindex’ command puts all the entries from the 'from'
index (the redirected index) into the ‘@code’ font, overriding whatever
default font is used by the index to which the entries are now directed.
This way, if you direct function names from a function index into a
concept index, all the function names are printed in the ‘@code’ font as
you would expect.


File: texinfo.info,  Node: @synindex,  Prev: @syncodeindex,  Up: Combining Indices

10.6.2 ‘@synindex’: Combining Indices
-------------------------------------

The ‘@synindex’ command is nearly the same as the ‘@syncodeindex’
command, except that it does not put the 'from' index entries into the
‘@code’ font; rather it puts them in the roman font.  Thus, you use
‘@synindex’ when you merge a concept index into a function index.

   *Note Printing Indices & Menus::, for information about printing an
index at the end of a book or creating an index menu in an Info file.


File: texinfo.info,  Node: New Indices,  Prev: Combining Indices,  Up: Indices

10.7 Defining New Indices
=========================

In addition to the predefined indices (*note Predefined Indices::), you
may use the ‘@defindex’ and ‘@defcodeindex’ commands to define new
indices.  These commands create new indexing @-commands with which you
mark index entries.  The ‘@defindex’ command is used like this:

     @defindex NAME

   New index names are usually two-letter words, such as ‘au’.  For
example:

     @defindex au

   This defines a new index, called the ‘au’ index.  At the same time,
it creates a new indexing command, ‘@auindex’, that you can use to make
index entries.  Use this new indexing command just as you would use a
predefined indexing command.

   For example, here is a section heading followed by a concept index
entry and two ‘au’ index entries.

     @section Cognitive Semantics
     @cindex kinesthetic image schemas
     @auindex Johnson, Mark
     @auindex Lakoff, George

(Evidently, ‘au’ serves here as an abbreviation for "author".)

   Texinfo constructs the new indexing command by concatenating the name
of the index with ‘index’; thus, defining an ‘xy’ index leads to the
automatic creation of an ‘@xyindex’ command.

   Use the ‘@printindex’ command to print the index, as you do with the
predefined indices.  For example:

     @node Author Index
     @unnumbered Author Index

     @printindex au

   The ‘@defcodeindex’ command is like the ‘@defindex’ command, except
that, in the printed output, it prints entries in an ‘@code’ font by
default instead of in a roman font.

   You should define new indices before the end-of-header line of a
Texinfo file, and (of course) before any ‘@synindex’ or ‘@syncodeindex’
commands (*note Texinfo File Header::).

   As mentioned earlier (*note Predefined Indices::), we recommend
having a single index in the final document whenever possible (no matter
how many source indices you use), since then readers have only one place
to look.

   When creating an index, TeX creates a file whose extension is the
name of the index (*note Names of index files::).  Therefore you should
avoid using index names that collide with extensions used for other
purposes, such as ‘.aux’ or ‘.xml’.  ‘texi2any’ already reports an error
if a new index conflicts well-known extension name.


File: texinfo.info,  Node: Insertions,  Next: Breaks,  Prev: Indices,  Up: Top

11 Special Insertions
*********************

Texinfo provides several commands for inserting characters that have
special meaning in Texinfo, such as braces, and for other graphic
elements that do not correspond to simple characters you can type.

* Menu:

* Special Characters::         Inserting @ {} , \ # &
* Inserting Quote Characters:: Inserting left and right quotes, in code.
* Inserting Space::            Inserting the right amount of whitespace.
* Inserting Accents::          Inserting accents and special characters.
* Inserting Quotation Marks::  Inserting quotation marks.
* Inserting Subscripts and Superscripts::  Inserting sub/superscripts.
* Inserting Math::             Formatting mathematical expressions.
* Glyphs for Text::            Inserting dots, bullets, currencies, etc.
* Glyphs for Programming::     Indicating results of evaluation, expansion of
                               macros, errors, etc.
* Inserting Unicode::          Inserting a Unicode character by code point.


File: texinfo.info,  Node: Special Characters,  Next: Inserting Quote Characters,  Up: Insertions

11.1 Special Characters: Inserting @ {} , \ # &
===============================================

‘@’ and curly braces are the basic special characters in Texinfo.  To
insert these characters so they appear in text, you must put an ‘@’ in
front of these characters to prevent Texinfo from misinterpreting them.
Alphabetic commands are also provided.

   The other characters (comma, backslash, hash, ampersand) are special
only in restricted contexts, as explained in the respective sections.

* Menu:

* Inserting an Atsign::        ‘@@’, ‘@atchar{}’.
* Inserting Braces::           ‘@{ @}’, ‘@l rbracechar{}’.
* Inserting a Comma::          , and ‘@comma{}’.
* Inserting a Backslash::      \ and ‘@backslashchar{}’.
* Inserting a Hashsign::       # and ‘@hashchar{}’.
* Inserting an Ampersand::     & and ‘@ampchar{}’.


File: texinfo.info,  Node: Inserting an Atsign,  Next: Inserting Braces,  Up: Special Characters

11.1.1 Inserting '@' with ‘@@’ and ‘@atchar{}’
----------------------------------------------

‘@@’ produces a single ‘@’ character in the output.  Do not put braces
after an ‘@@’ command.

   ‘@atchar{}’ also produces a single ‘@’ character in the output.  It
does need following braces, as usual for alphabetic commands.  In inline
conditionals (*note Inline Conditionals::), it can be necessary to avoid
using the literal ‘@’ character in the source (and may be clearer in
other contexts).


File: texinfo.info,  Node: Inserting Braces,  Next: Inserting a Comma,  Prev: Inserting an Atsign,  Up: Special Characters

11.1.2 Inserting '{ '}' with ‘@{ @}’ and ‘@l rbracechar{}’
----------------------------------------------------------

‘@{’ produces a single ‘{’ in the output, and ‘@}’ produces a single
‘}’.  Do not put braces after either an ‘@{’ or an ‘@}’ command.

   ‘@lbracechar{}’ and ‘@rbracechar{}’ also produce single ‘{’ and ‘}’
characters in the output.  They do need following braces, as usual for
alphabetic commands.  In inline conditionals (*note Inline
Conditionals::), it can be necessary to avoid using literal brace
characters in the source (and may be clearer in other contexts).


File: texinfo.info,  Node: Inserting a Comma,  Next: Inserting a Backslash,  Prev: Inserting Braces,  Up: Special Characters

11.1.3 Inserting ',' with ‘@comma{}’
------------------------------------

Ordinarily, a comma ',' is a normal character that can be simply typed
in your input where you need it.

   However, Texinfo uses the comma as a special character only in one
context: to separate arguments to those Texinfo commands, such as
‘@node’ (*note Node Line Requirements::), ‘@acronym’ (*note @acronym::)
and ‘@xref’ (*note Cross References::), as well as user-defined macros
(*note Defining Macros::), which take more than one argument.

   Since a comma character would confuse Texinfo's parsing for these
commands, you must use the command ‘@comma{}’ instead if you want to
pass an actual comma.  Here are some examples:

     @acronym{ABC, A Bizarre @comma{}}
     @xref{Comma,, The @comma{} symbol}
     @mymac{One argument@comma{} containing a comma}

   Although ‘@comma{}’ can be used nearly anywhere, there is no need for
it anywhere except in this unusual case.

   (Incidentally, the name ‘@comma’ lacks the ‘char’ suffix used in its
companion commands only for historical reasons.  It didn't seem
important enough to define a synonym.)


File: texinfo.info,  Node: Inserting a Backslash,  Next: Inserting a Hashsign,  Prev: Inserting a Comma,  Up: Special Characters

11.1.4 Inserting '\' with ‘@backslashchar{}’
--------------------------------------------

Ordinarily, a backslash '\' is a normal character in Texinfo that can be
simply typed in your input where you need it.  The result is to typeset
the backslash from the typewriter font.

   However, Texinfo uses the backslash as a special character in one
restricted context: to delimit formal arguments in the bodies of
user-defined macros (*note Defining Macros::).

   Due to the vagaries of macro argument parsing, it is more reliable to
pass an alphabetic command that produces a backslash instead of using a
literal \.  Hence ‘@backslashchar{}’.  Here is an example macro call:

     @mymac{One argument@backslashchar{} with a backslash}

   Texinfo documents may also use \ as a command character inside
‘@math’ (*note Inserting Math::).  In this case, ‘@\’ or ‘\backslash’
produce a "math" backslash (from the math symbol font), while
‘@backslashchar{}’ produces a typewriter backslash as usual.

   Although ‘@backslashchar{}’ can be used nearly anywhere, there is no
need for it except in these unusual cases.

