Merged in changes from CVS HEAD

[emacs.git] / man / cc-mode.texi

\input texinfo

@c Notes to self regarding line handling:
@c
@c Empty lines are often significant before @end directives; avoid them.
@c
@c Empty lines before and after @example directives are significant in
@c info output but not in TeX.  Empty lines inside @example directives
@c are significant.

@c Conventions for formatting examples:
@c o  If the example contains empty lines then put the surrounding empty
@c    lines inside the @example directives.  Put them outside otherwise.
@c o  Use @group inside the example only if it shows indentation where
@c    the relation between lines inside is relevant.
@c o  Format line number columns like this:
@c     1: foo
@c     2: bar
@c       ^ one space
@c    ^^ two columns, right alignment
@c o  Check line lengths in TeX output; they can typically be no longer
@c    than 70 chars, 60 if the paragraph is indented.

@comment TBD: Document the finer details of statement anchoring?

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment %**start of header (This is for running Texinfo on a region)
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@comment No overfull hbox marks in the dvi file.
@finalout

@setfilename  ../info/ccmode
@settitle     CC Mode Manual
@footnotestyle end

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment @setchapternewpage odd !! we don't want blank pages !!
@comment %**end of header (This is for running Texinfo on a region)
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment 
@comment Texinfo manual for CC Mode
@comment Generated from the original README file by Krishna Padmasola
@comment <krishna@earth-gw.njit.edu>
@comment
@comment Authors:
@comment Barry A. Warsaw
@comment Martin Stjernholm
@comment
@comment Maintained by Martin Stjernholm <bug-cc-mode@gnu.org>
@comment 
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@comment Define an index for syntactic symbols.
@defindex ss

@comment Combine key, syntactic symbol and concept indices into one.
@syncodeindex ss cp
@syncodeindex ky cp

@copying
This manual is for CC Mode in Emacs.

Copyright @copyright{} 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
2003 Free Software Foundation, Inc.

@quotation
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``The GNU Manifesto'', ``Distribution'' and
``GNU GENERAL PUBLIC LICENSE'', with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.
@end quotation
@end copying

@comment Info directory entry for use by install-info. The indentation
@comment here is by request from the FSF folks.
@dircategory Emacs
@direntry
* CC Mode: (ccmode).    Emacs mode for editing C, C++, Objective-C,
                        Java, Pike, AWK, and CORBA IDL code.
@end direntry

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment TeX title page
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@titlepage
@sp 10

@center @titlefont{CC Mode 5.30}
@sp 2
@center @subtitlefont{A GNU Emacs mode for editing C and C-like languages}
@sp 2
@center Barry A. Warsaw, Martin Stjernholm, Alan Mackenzie (AWK support)

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

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment The Top node contains the master menu for the Info file.
@comment This appears only in the Info file, not the printed manual.
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@node    Top, Introduction, (dir), (dir)
@comment node-name, next, previous, up

@macro ccmode
CC Mode
@end macro

@ifinfo
@top @ccmode{}

@ccmode{} is a GNU Emacs mode for editing files containing C, C++,
Objective-C, Java, CORBA IDL (and the variants PSDL and CIDL), Pike
code and to a certain extent, AWK code @xref{AWK Mode}.  It provides
syntax-based indentation, font locking, and has several handy commands
and some minor modes to make the editing easier.  It does not provide
tools to look up and navigate between functions, classes etc - there are
other packages for that.
@end ifinfo

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@menu
* Introduction::
* Getting Connected::
* Indentation Engine::
* Minor Modes::
* Text Filling and Line Breaking::
* Macro Handling::
* Font Locking::
* Commands::
* Customizing Indentation::
* Syntactic Symbols::
* Indentation Functions::
* AWK Mode::
* Odds and Ends::
* Performance Issues::
* Limitations and Known Bugs::
* Frequently Asked Questions::
* Getting the Latest CC Mode Release::
* Mailing Lists and Submitting Bug Reports::
* Sample .emacs File::

 --- Indices ---

* Command and Function Index::
* Variable Index::
* Concept Index::

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

Indentation Engine

* Syntactic Analysis::
* Indentation Calculation::

Minor Modes

* Auto-newline Insertion::
* Hungry-deletion of Whitespace::

Font Locking

* Font Locking Preliminaries::
* Faces::
* Documentation Comments::

Auto-newline Insertion

* Hanging Braces::
* Hanging Colons::
* Hanging Semicolons and Commas::
* Other Electric Commands::
* Clean-ups::

Commands

* Indentation Commands::
* Movement Commands::
* Other Commands::

Customizing Indentation

* Interactive Customization::
* Permanent Customization::
* Hooks::
* Styles::
* Advanced Customizations::

Styles

* Built-in Styles::
* Choosing a Style::
* Adding Styles::
* File Styles::

Advanced Customizations

* Custom Indentation Functions::
* Custom Brace and Colon Hanging::
* Customizing Semicolons and Commas::
* Other Special Indentations::

AWK Mode

* Initialising AWK Mode::
* AWK Mode Font Locking::
* AWK Mode Defuns::
@end detailmenu
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Introduction, Getting Connected, Top, Top
@comment node-name, next, previous, up
@chapter Introduction
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex BOCM

Welcome to @ccmode{}, a GNU Emacs mode for editing files containing C,
C++, Objective-C, Java, CORBA IDL (and the variants CORBA PSDL and
CIDL), Pike and to a certain extent, AWK code (@pxref{AWK Mode}).  This
incarnation of the mode is descended from @file{c-mode.el} (also called
``Boring Old C Mode'' or BOCM @t{:-)}, and @file{c++-mode.el} version 2,
which Barry has been maintaining since 1992.  Late in 1997, Martin
joined the @ccmode{} Maintainers Team, and implemented the Pike support.
As of 2000 Martin has taken over as the sole maintainer.  @ccmode{} did
not originally contain the font lock support for its languages --- that
was added in version 5.30.  AWK support was also added in 5.30 by Alan
Mackenzie.

This manual describes @ccmode{}
@comment The following line must appear on its own, so that the automated
version 5.30.
@comment Release.py script can update the version number automatically

@ccmode{} supports the editing of K&R and ANSI C, C++, Objective-C,
Java, CORBA's Interface Definition Language, Pike@footnote{A C-like
scripting language with its roots in the LPC language used in some MUD
engines.  See @uref{http://pike.ida.liu.se/}.} and AWK files.  In this
way, you can easily set up consistent font locking and coding styles for
use in editing all of these languages, although AWK is not yet as
uniformly integrated as the other languages.

@findex c-mode
@findex c++-mode
@findex objc-mode
@findex java-mode
@findex idl-mode
@findex pike-mode
@findex awk-mode
Note that the name of this package is ``@ccmode{},'' but there is no top
level @code{cc-mode} entry point.  All of the variables, commands, and
functions in @ccmode{} are prefixed with @code{c-@var{thing}}, and
@code{c-mode}, @code{c++-mode}, @code{objc-mode}, @code{java-mode},
@code{idl-mode}, @code{pike-mode}, and @code{awk-mode} entry points are
provided.  This package is intended to be a replacement for
@file{c-mode.el}, @file{c++-mode.el} and @file{awk-mode.el}.

@c @cindex @file{cc-compat.el} file
@c This distribution also contains a file
@c called @file{cc-compat.el} which should ease your transition from BOCM
@c to @ccmode{}.  If you have a BOCM configuration you are really happy
@c with, and want to postpone learning how to configure @ccmode{}, take a
@c look at that file.  It maps BOCM configuration variables to @ccmode{}'s
@c indentation model.  It is not actively supported so for the long run,
@c you should learn how to customize @ccmode{} to support your coding
@c style.

A special word of thanks goes to Krishna Padmasola for his work in
converting the original @file{README} file to Texinfo format.  I'd also
like to thank all the @ccmode{} victims who help enormously during the
early beta stages of @ccmode{}'s development.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Getting Connected, Indentation Engine, Introduction, Top
@comment node-name, next, previous, up
@chapter Getting Connected
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If you got this version of @ccmode{} with Emacs or XEmacs, it should
work just fine right out of the box.  Note however that you may not have
the latest @ccmode{} release and may want to upgrade your copy.

If you are upgrading an existing @ccmode{} installation, please see the
@file{README} file for installation details.  @ccmode{} may not work
with older versions of Emacs or XEmacs.  See the @ccmode{} release notes
at @uref{http://cc-mode.sourceforge.net} for the latest information on
Emacs version and package compatibility (@pxref{Getting the Latest CC
Mode Release}).

@deffn Command c-version
@findex version (c-)
You can find out what version of @ccmode{} you are using by visiting a C
file and entering @kbd{M-x c-version RET}.  You should see this message in
the echo area:

@example
Using CC Mode version 5.XX
@end example

@noindent
where @samp{XX} is the minor release number.
@end deffn


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Indentation Engine, Minor Modes, Getting Connected, Top
@comment node-name, next, previous, up
@chapter Indentation Engine
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} has an indentation engine that provides a flexible and general
mechanism for customizing indentation. It separates indentation
calculation into two steps: first, @ccmode{} analyzes the line of code
being indented to determine the kind of language construct it's looking
at, then it applies user defined offsets to the current line based on
this analysis.

This section will briefly cover how indentation is calculated in
@ccmode{}. It is important to understand the indentation model being
used so that you will know how to customize @ccmode{} for your personal
coding style.  All the details are in @ref{Customizing Indentation}, and
later chapters.

@defopt c-syntactic-indentation
@vindex syntactic-indentation (c-)
Syntactic analysis for indentation is done when this is non-@code{nil}
(which is the default).  When it's @code{nil} every line is just
indented to the same level as the previous one, and @kbd{TAB}
(@code{c-indent-command}) adjusts the indentation in steps of
@code{c-basic-offset}.  The indentation style has no effect, nor any of
the indentation associated variables, e.g. @code{c-special-indent-hook}.
@end defopt

@menu
* Syntactic Analysis::
* Indentation Calculation::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Syntactic Analysis, Indentation Calculation, , Indentation Engine
@comment node-name, next, previous, up
@section Syntactic Analysis
@cindex syntactic analysis
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex relative buffer position
@cindex syntactic symbols
@cindex syntactic component
@cindex syntactic component list
The first thing @ccmode{} does when indenting a line of code, is to
analyze the line, determining the @dfn{syntactic component list} of the
construct on that line.  A syntactic component consists of a pair of
elements (in lisp parlance, a @emph{cons cell}), the first being
a @dfn{syntactic symbol}, the second being a @dfn{relative
buffer position}.  Syntactic symbols describe elements of C code
@footnote{Unless otherwise noted, the term ``C code'' refers to all
the C-like languages.}, e.g. @code{statement}, @code{substatement},
@code{class-open}, @code{class-close}, etc.  @xref{Syntactic Symbols},
for a complete list of currently recognized syntactic symbols and their
semantics.  The style variable @code{c-offsets-alist} also contains the
list of currently supported syntactic symbols.

Conceptually, a line of C code is always indented relative to the
indentation of some line higher up in the buffer.  This is represented
by the relative buffer position in the syntactic component.

Here is an example.  Suppose we had the following code as the only thing
in a C++ buffer @footnote{The line numbers in this and future examples
don't actually appear in the buffer, of course!}:

@example
 1: void swap( int& a, int& b )
 2: @{
 3:     int tmp = a;
 4:     a = b;
 5:     b = tmp;
 6: @}
@end example

@kindex C-c C-s
@findex c-show-syntactic-information
@findex show-syntactic-information (c-)
We can use the command @kbd{C-c C-s} (bound to
@code{c-show-syntactic-information}) to simply report what the
syntactic analysis is for the current line.  Running this command on
line 4 of this example, we'd see in the echo area@footnote{With a
universal argument (i.e. @kbd{C-u C-c C-s}) the analysis is inserted
into the buffer as a comment on the current line.}:

@example
((statement 35))
@end example

This tells us that the line is a statement and it is indented relative
to buffer position 35, which happens to be the @samp{i} in @code{int} on
line 3.  If you were to move point to line 3 and hit @kbd{C-c C-s}, you
would see:

@example
((defun-block-intro 29))
@end example

This indicates that the @samp{int} line is the first statement in a top
level function block, and is indented relative to buffer position 29,
which is the brace just after the function header.

Here's another example:

@example
 1: int add( int val, int incr, int doit )
 2: @{
 3:     if( doit )
 4:         @{
 5:             return( val + incr );
 6:         @}
 7:     return( val );
 8: @}
@end example

@noindent
Hitting @kbd{C-c C-s} on line 4 gives us:

@example
((substatement-open 46))
@end example

@cindex substatement
@cindex substatement block
@noindent
which tells us that this is a brace that @emph{opens} a substatement
block. @footnote{A @dfn{substatement} is the line after a
conditional statement, such as @code{if}, @code{else}, @code{while},
@code{do}, @code{switch}, etc.  A @dfn{substatement
block} is a brace block following one of these conditional statements.}

@cindex comment-only line
Syntactic component lists can contain more than one component, and
individual syntactic components need not have relative buffer positions.
The most common example of this is a line that contains a @dfn{comment
only line}.

@example
 1: void draw_list( List<Drawables>& drawables )
 2: @{
 3:         // call the virtual draw() method on each element in list
 4:     for( int i=0; i < drawables.count(), ++i )
 5:     @{
 6:         drawables[i].draw();
 7:     @}
 8: @}
@end example

@noindent
Hitting @kbd{C-c C-s} on line 3 of this example gives:

@example
((comment-intro) (defun-block-intro 46))
@end example

@noindent
and you can see that the syntactic component list contains two syntactic
components.  Also notice that the first component,
@samp{(comment-intro)} has no relative buffer position.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Indentation Calculation, , Syntactic Analysis, Indentation Engine
@comment node-name, next, previous, up
@section Indentation Calculation
@cindex indentation
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Indentation for a line is calculated using the syntactic
component list derived in step 1 above (@pxref{Syntactic Analysis}).
Each component contributes to the final total indentation of the line in
two ways.

First, the syntactic symbols are looked up in the @code{c-offsets-alist}
style variable, which is an association list of syntactic symbols and
the offsets to apply for those symbols.  These offsets are added to a
running total.

Second, if the component has a relative buffer position, @ccmode{}
adds the column number of that position to the running total.  By adding
up the offsets and columns for every syntactic component on the list,
the final total indentation for the current line is computed.

Let's use our two code examples above to see how this works.  Here is
our first example again:

@example
 1: void swap( int& a, int& b )
 2: @{
 3:     int tmp = a;
 4:     a = b;
 5:     b = tmp;
 6: @}
@end example

Let's say point is on line 3 and we hit the @kbd{TAB} key to reindent
the line.  Remember that the syntactic component list for that
line is:

@example
((defun-block-intro 29))
@end example

@noindent
@ccmode{} looks up @code{defun-block-intro} in the
@code{c-offsets-alist} style variable.  Let's say it finds the value
@samp{4}; it adds this to the running total (initialized to zero),
yielding a running total indentation of 4 spaces.

Next @ccmode{} goes to buffer position 29 and asks for the current
column.  This brace is in column zero, so @ccmode{}
adds @samp{0} to the running total.  Since there is only one syntactic
component on the list for this line, indentation calculation is
complete, and the total indentation for the line
is 4 spaces.

Here's another example:

@example
 1: int add( int val, int incr, int doit )
 2: @{
 3:     if( doit )
 4:         @{
 5:             return( val + incr );
 6:         @}
 7:     return( val );
 8: @}
@end example

If we were to hit @kbd{TAB} on line 4 in the above example, the same
basic process is performed, despite the differences in the syntactic
component list.  Remember that the list for this line is:

@example
((substatement-open 46))
@end example

Here, @ccmode{} first looks up the @code{substatement-open} symbol
in @code{c-offsets-alist}. Let's say it finds the value @samp{4}.  This
yields a running total of 4.  @ccmode{} then goes to
buffer position 46, which is the @samp{i} in @code{if} on line 3.  This
character is in the fourth column on that line so adding this to the
running total yields an indentation for the line of 8 spaces.

Simple, huh?

Actually, the mode usually just does The Right Thing without you having
to think about it in this much detail.  But when customizing
indentation, it's helpful to understand the general indentation model
being used.

As you configure @ccmode{}, you might want to set the variable
@code{c-echo-syntactic-information-p} to non-@code{nil} so that the
syntactic component list and calculated offset will always be echoed in
the minibuffer when you hit @kbd{TAB}.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Minor Modes, Text Filling and Line Breaking, Indentation Engine, Top
@comment node-name, next, previous, up
@chapter Minor Modes
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} contains two minor-mode-like features that you should
find useful while entering new C code.  The first is called
@dfn{auto-newline} mode, and the second is called @dfn{hungry-delete}
mode.  These minor modes can be toggled on and off independently, and
@ccmode{} can be configured so that it starts up with any
combination of these minor modes.  By default, both of these minor modes
are turned off.

The state of the minor modes is always reflected in the minor mode list
on the modeline of the @ccmode{} buffer.  When auto-newline mode is
enabled, you will see @samp{C/a} on the mode line@footnote{The @samp{C}
would be replaced with the name of the language in question for the
other languages @ccmode{} supports.}.  When hungry delete mode is
enabled you will see @samp{C/h} and if both modes were enabled, you'd
see @samp{C/ah}.

@kindex C-c C-a
@kindex C-c C-d
@kindex C-c C-t
@findex c-toggle-hungry-state
@findex c-toggle-auto-state
@findex c-toggle-auto-hungry-state
@findex toggle-hungry-state (c-)
@findex toggle-auto-state (c-)
@findex toggle-auto-hungry-state (c-)
@ccmode{} provides key bindings which allow you to toggle the minor
modes on the fly while editing code.  To toggle just the auto-newline
state, hit @kbd{C-c C-a} (bound to @code{c-toggle-auto-state}).  When
you do this, you should see the @samp{a} indicator either appear or
disappear on the modeline.  Similarly, to toggle just the
hungry-delete state, use @kbd{C-c C-d} (@code{c-toggle-hungry-state}),
and to toggle both states, use @kbd{C-c C-t}
(@code{c-toggle-auto-hungry-state}).

To set up the auto-newline and hungry-delete states to your preferred
values, you would need to add some lisp to your @file{.emacs} file that
called one of the @code{c-toggle-*-state} functions directly.  When
called programmatically, each function takes a numeric value, where
a positive number enables the minor mode, a negative number disables the
mode, and zero toggles the current state of the mode.

So for example, if you wanted to enable both auto-newline and
hungry-delete for all your C file editing, you could add the following
to your @file{.emacs} file:

@example
(add-hook 'c-mode-common-hook
          (lambda () (c-toggle-auto-hungry-state 1)))
@end example

@menu
* Auto-newline Insertion::
* Hungry-deletion of Whitespace::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Auto-newline Insertion, Hungry-deletion of Whitespace, , Minor Modes
@comment node-name, next, previous, up
@section Auto-newline Insertion
@cindex auto-newline
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex electric characters
Auto-newline minor mode works by enabling certain @dfn{electric
characters}.  Special characters such as the left and right braces,
colons, semicolons, etc., have been made electric to perform some
magic formatting in addition to inserting the typed character.  As a
general rule, electric characters are only electric when the following
conditions apply:

@itemize @bullet
@item
Auto-newline minor mode is enabled, as evidenced by a @samp{C/a} or
@samp{C/ah} indicator on the modeline.

@item
@cindex literal
@cindex syntactic whitespace
The character was not typed inside of a literal @footnote{A
@dfn{literal} is defined as any comment, string, or preprocessor macro
definition.  These constructs are also known as @dfn{syntactic
whitespace} since they are usually ignored when scanning C code.}.

@item
No numeric argument was supplied to the command (i.e. it was typed as
normal, with no @kbd{C-u} prefix).
@end itemize

@menu
* Hanging Braces::
* Hanging Colons::
* Hanging Semicolons and Commas::
* Other Electric Commands::
* Clean-ups::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Hanging Braces, Hanging Colons, , Auto-newline Insertion
@comment node-name, next, previous, up
@subsection Hanging Braces
@cindex hanging braces
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@findex c-electric-brace
@findex electric-brace (c-)
@kindex @{
@kindex @}

When you type either an open or close brace (i.e. @kbd{@{} or @kbd{@}}),
the electric command @code{c-electric-brace} gets run.  This command has
two electric formatting behaviors.  First, it will perform some
reindentation of the line the brace was typed on, and second, it will
add various newlines before and/or after the typed brace.
Reindentation occurs automatically whenever the electric behavior is
enabled.  If the brace ends up on a line other than the one it was typed
on, then that line is also reindented.

The default in auto-newline mode is to insert newlines both before and
after a brace, but that can be controlled by the
@code{c-hanging-braces-alist} style variable.

@defopt c-hanging-braces-alist
@vindex hanging-braces-alist (c-)

This variable contains a mapping between syntactic symbols related to
braces, and a list of places to insert a newline.  The syntactic symbols
that are useful for this list are @code{brace-list-intro},
@code{statement-cont}, @code{inexpr-class-open},
@code{inexpr-class-close}, and all the @code{*-open} and @code{*-close}
symbols.  @xref{Syntactic Symbols}, for a more detailed description of
these syntactic symbols, except for @code{inexpr-class-open} and
@code{inexpr-class-close}, which aren't actual syntactic symbols.

The braces of anonymous inner classes in Java are given the special
symbols @code{inexpr-class-open} and @code{inexpr-class-close}, so that
they can be distinguished from the braces of normal classes@footnote{The
braces of anonymous classes produce a combination of
@code{inexpr-class}, and @code{class-open} or @code{class-close} in
normal indentation analysis.}.

Note that the aggregate constructs in Pike mode, @samp{(@{}, @samp{@})},
@samp{([}, @samp{])}, and @samp{(<}, @samp{>)}, do not count as brace
lists in this regard, even though they do for normal indentation
purposes.  It's currently not possible to set automatic newlines on
these constructs.

The value associated with each syntactic symbol in this association list
is called an @var{action}, which can be either a function or a list.
@xref{Custom Brace and Colon Hanging}, for a more detailed discussion of
using a function as a brace hanging @var{action}.

When the @var{action} is a list, it can contain any combination of the
symbols @code{before} and @code{after}, directing @ccmode{} where to
put newlines in relationship to the brace being inserted.  Thus, if the
list contains only the symbol @code{after}, then the brace is said to
@dfn{hang} on the right side of the line, as in:

@example
// here, open braces always `hang'
void spam( int i ) @{
    if( i == 7 ) @{
        dosomething(i);
    @}
@}
@end example

When the list contains both @code{after} and @code{before}, the braces
will appear on a line by themselves, as shown by the close braces in the
above example.  The list can also be empty, in which case no newlines
are added either before or after the brace.

If a syntactic symbol is missing entirely from
@code{c-hanging-braces-alist}, it's treated in the same way as an
@var{action} with a list containing @code{before} and @code{after}, so
that braces by default end up on their own line.

For example, the default value of @code{c-hanging-braces-alist} is:

@example
((brace-list-open)
 (brace-entry-open)
 (statement-cont)
 (substatement-open after)
 (block-close . c-snug-do-while)
 (extern-lang-open after)
 (inexpr-class-open after)
 (inexpr-class-close before))
@end example

@noindent which says that @code{brace-list-open},
@code{brace-entry-open} and @code{statement-cont}@footnote{Brace lists
inside statements, such as initializers for static array variables
inside functions in C, are recognized as @code{statement-cont}.  All
normal substatement blocks are recognized with other symbols.} braces
should both hang on the right side and allow subsequent text to follow
on the same line as the brace.  Also, @code{substatement-open},
@code{extern-lang-open}, and @code{inexpr-class-open} braces should hang
on the right side, but subsequent text should follow on the next line.
The opposite holds for @code{inexpr-class-close} braces; they won't
hang, but the following text continues on the same line.  Here, in the
@code{block-close} entry, you also see an example of using a function as
an @var{action}.  In all other cases, braces are put on a line by
themselves.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Hanging Colons, Hanging Semicolons and Commas, Hanging Braces, Auto-newline Insertion
@comment node-name, next, previous, up
@subsection Hanging Colons
@cindex hanging colons
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Using a mechanism similar to brace hanging (@pxref{Hanging Braces}),
colons can also be made to hang using the style variable
@code{c-hanging-colons-alist}.

@defopt c-hanging-colons-alist
@vindex hanging-colons-alist (c-)

The syntactic symbols appropriate for this association list are:
@code{case-label}, @code{label}, @code{access-label},
@code{member-init-intro}, and @code{inher-intro}.  Note however that for
@code{c-hanging-colons-alist}, @var{action}s as functions are not
supported. See also @ref{Custom Brace and Colon Hanging} for details.

In C++, double-colons are used as a scope operator but because these
colons always appear right next to each other, newlines before and after
them are controlled by a different mechanism, called @dfn{clean-ups} in
@ccmode{}.  @xref{Clean-ups}, for details.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Hanging Semicolons and Commas, Other Electric Commands, Hanging Colons, Auto-newline Insertion
@comment node-name, next, previous, up
@subsection Hanging Semicolons and Commas
@cindex hanging semicolons
@cindex hanging commas
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Semicolons and commas are also electric in @ccmode{}, but since
these characters do not correspond directly to syntactic symbols, a
different mechanism is used to determine whether newlines should be
automatically inserted after these characters.  @xref{Customizing
Semicolons and Commas}, for details.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Other Electric Commands, Clean-ups, Hanging Semicolons and Commas, Auto-newline Insertion
@comment node-name, next, previous, up
@subsection Other Electric Commands
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

A few other keys also provide electric behavior, often only to reindent
the line.  Common to all of them is that they only reindent if used in
normal code (as opposed to in a string literal or comment), and
@code{c-syntactic-indentation} isn't @code{nil}.  They are:

@table @kbd
@item #
@kindex #
@findex c-electric-pound
@findex electric-pound (c-)
@vindex c-electric-pound-behavior
@vindex electric-pound-behavior (c-)
Pound (bound to @code{c-electric-pound}) is electric when typed as the
first non-whitespace character on a line and not within a macro
definition.  In this case, the variable @code{c-electric-pound-behavior}
is consulted for the electric behavior.  This variable takes a list
value, although the only element currently defined is @code{alignleft},
which tells this command to force the @samp{#} character into column
zero.  This is useful for entering preprocessor macro definitions.

Pound is not electric in AWK buffers, where @samp{#} starts a comment,
and is bound to @code{self-insert-command} like any typical printable
character.

@item *
@kindex *
@itemx /
@kindex /
@findex c-electric-star
@findex electric-star (c-)
@findex c-electric-slash
@findex electric-slash (c-)
Stars and slashes (bound to @code{c-electric-star} and
@code{c-electric-slash} respectively) are also electric under certain
circumstances.  If a @samp{*} is inserted as the second character of a C
style block comment on a comment-only line, then the comment delimiter
is indented as defined by @code{c-offsets-alist}.  A comment-only line
is defined as a line which contains only a comment, as in:

@example
@group
void spam( int i )
@{
    // this is a comment-only line...
    if( i == 7 )                // but this is not
    @{
        dosomething(i);
    @}
@}
@end group
@end example

Likewise, if a @samp{/} is inserted as the second slash in a C++ style
line comment (also only on a comment-only line), then the line is
indented as defined by @code{c-offsets-alist}.

In AWK mode, @samp{*} and @samp{/} do not delimit comments and are
bound to @code{self-insert-command}.

@item <
@kindex <
@itemx >
@kindex >
@findex c-electric-lt-gt
@findex electric-lt-gt (c-)
Less-than and greater-than signs (bound to @code{c-electric-lt-gt}) are
electric, but only in C++ mode.  Hitting the second of two @kbd{<} or
@kbd{>} keys reindents the line if it is a C++ style stream operator.

@item (
@kindex (
@itemx )
@kindex )
@findex c-electric-paren
@findex electric-paren (c-)
The normal parenthesis characters @samp{(} and @samp{)} reindent the
current line.  This is useful for getting the closing parenthesis of an
argument list aligned automatically.
@end table

@deffn Command c-electric-continued-statement
@findex electric-continued-statement (c-)

Certain keywords, depending on language, are electric to cause
reindentation when they are preceded only by whitespace on the line.
The keywords are those that continue an earlier statement instead of
starting a new one: @code{else}, @code{while}, @code{catch} (only in C++
and Java) and @code{finally} (only in Java).

An example:

@example
@group
for (i = 0; i < 17; i++)
  if (a[i])
    res += a[i]->offset;
else
@end group
@end example

Here, the @code{else} should be indented like the preceding @code{if},
since it continues that statement. @ccmode{} will automatically reindent
it after the @code{else} has been typed in full, since it's not until
then it's possible to decide whether it's a new statement or a
continuation of the preceding @code{if}.

@vindex abbrev-mode
@findex abbrev-mode
@cindex Abbrev mode
@ccmode{} uses Abbrev mode (@pxref{Abbrevs,,, emacs, The Emacs Editor})
to accomplish this. It's therefore turned on by default in all language
modes except IDL mode, since CORBA IDL doesn't have any statements.
@end deffn


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Clean-ups, , Other Electric Commands, Auto-newline Insertion
@comment node-name, next, previous, up
@subsection Clean-ups
@cindex clean-ups
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@dfn{Clean-ups} are mechanisms complementary to colon and brace hanging.
On the surface, it would seem that clean-ups overlap the functionality
provided by the @code{c-hanging-*-alist} variables.  Clean-ups are
however used to adjust code ``after-the-fact,'' i.e. to adjust the
whitespace in constructs after they are typed.

Most of the clean-ups are only applicable to counteract automatically
inserted newlines, and will therefore only have any effect if the
auto-newline minor mode is turned on.  Others will work all the time.

@defopt c-cleanup-list
@vindex cleanup-list (c-)
@cindex literal

You can configure @ccmode{}'s clean-ups by setting the style variable
@code{c-cleanup-list}, which is a list of clean-up symbols.  By default,
@ccmode{} cleans up only the @code{scope-operator} construct, which is
necessary for proper C++ support.  Note that clean-ups are only
performed when the construct does not occur within a literal
(@pxref{Auto-newline Insertion}), and when there is nothing but
whitespace appearing between the individual components of the construct.
@end defopt

These are the clean-ups that are only active in the auto-newline minor
mode:

@c TBD: Would like to use some sort of @deffoo here; @table indents a
@c bit too much in dvi output.
@table @code
@item brace-else-brace
Clean up @samp{@} else @{} constructs by placing the entire construct on
a single line.  Clean-up occurs when the open brace after the
@samp{else} is typed.  So for example, this:

@example
@group
void spam(int i)
@{
    if( i==7 ) @{
        dosomething();
    @}
    else
    @{
@end group
@end example

@noindent
appears like this after the last open brace is typed:

@example
@group
void spam(int i)
@{
    if( i==7 ) @{
        dosomething();
    @} else @{
@end group
@end example

@item brace-elseif-brace
Similar to the @code{brace-else-brace} clean-up, but this cleans up
@samp{@} else if (...) @{} constructs.  For example:

@example
@group
void spam(int i)
@{
    if( i==7 ) @{
        dosomething();
    @}
    else if( i==3 )
    @{
@end group
@end example

@noindent
appears like this after the last open parenthesis is typed:

@example
@group
void spam(int i)
@{
    if( i==7 ) @{
        dosomething();
    @} else if( i==3 )
    @{
@end group
@end example

@noindent
and like this after the last open brace is typed:

@example
@group
void spam(int i)
@{
    if( i==7 ) @{
        dosomething();
    @} else if( i==3 ) @{
@end group
@end example

@item brace-catch-brace
Analogous to @code{brace-elseif-brace}, but cleans up @samp{@} catch
(...) @{} in C++ and Java mode.

@item empty-defun-braces
Clean up braces following a top-level function or class definition that
contains no body.  Clean up occurs when the closing brace is typed.
Thus the following:

@example
@group
class Spam
@{
@}
@end group
@end example

@noindent
is transformed into this when the close brace is typed:

@example
@group
class Spam
@{@}
@end group
@end example

@item defun-close-semi
Clean up the terminating semicolon on top-level function or class
definitions when they follow a close brace.  Clean up occurs when the
semicolon is typed.  So for example, the following:

@example
@group
class Spam
@{
@}
;
@end group
@end example

@noindent
is transformed into this when the semicolon is typed:

@example
@group
class Spam
@{
@};
@end group
@end example

@item list-close-comma
Clean up commas following braces in array and aggregate initializers.
Clean up occurs when the comma is typed.

@item scope-operator
Clean up double colons which may designate a C++ scope operator split
across multiple lines@footnote{Certain C++ constructs introduce
ambiguous situations, so @code{scope-operator} clean-ups may not always
be correct.  This usually only occurs when scoped identifiers appear in
switch label tags.}.  Clean up occurs when the second colon is typed.
You will always want @code{scope-operator} in the @code{c-cleanup-list}
when you are editing C++ code.
@end table

The following clean-ups are always active when they occur on
@code{c-cleanup-list}, and are thus not affected by the auto-newline
minor mode:

@table @code
@item space-before-funcall
Insert a space between the function name and the opening parenthesis of
a function call.  This produces function calls in the style mandated by
the GNU coding standards, e.g. @samp{signal (SIGINT, SIG_IGN)} and
@samp{abort ()}.  Clean up occurs when the opening parenthesis is typed.

@item compact-empty-funcall
Clean up any space between the function name and the opening parenthesis
of a function call that has no arguments.  This is typically used
together with @code{space-before-funcall} if you prefer the GNU function
call style for functions with arguments but think it looks ugly when
it's only an empty parenthesis pair.  I.e. you will get @samp{signal
(SIGINT, SIG_IGN)}, but @samp{abort()}.  Clean up occurs when the
closing parenthesis is typed.
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Hungry-deletion of Whitespace, , Auto-newline Insertion, Minor Modes
@comment node-name, next, previous, up
@section Hungry-deletion of Whitespace
@cindex hungry-deletion
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hungry deletion of whitespace, or as it more commonly called,
@dfn{hungry-delete mode}, is a simple feature that some people find
extremely useful.  In fact, you might find yourself wanting
hungry-delete in @strong{all} your editing modes!

@kindex DEL
@kindex C-d

In a nutshell, when hungry-delete mode is enabled, hitting the @kbd{DEL}
or @kbd{C-d} keys will consume all preceding or following whitespace,
including newlines and tabs.  This can really cut down on the number of
times you have to hit these keys if, for example, you made a mistake on
the preceding line.

@deffn Command c-electric-backspace
@findex electric-backspace (c-)
This command is run by default when you hit the @kbd{DEL} key.  It
deletes any amount of whitespace in the backwards direction if
hungry-delete mode is enabled.  When it's disabled, or when used with
a prefix argument or in a literal (@pxref{Auto-newline Insertion}),
the function contained in the @code{c-backspace-function} variable is
called with the prefix argument.
@end deffn

@defvar c-backspace-function
@vindex backspace-function (c-)
@findex backward-delete-char-untabify
Hook that gets called by @code{c-electric-backspace} when it doesn't
do an ``electric'' deletion of the preceding whitespace.  The default
value is @code{backward-delete-char-untabify}.
@end defvar

@deffn Command c-electric-delete-forward
@findex electric-delete-forward (c-)
This function, which is bound to @kbd{C-d} by default, works just like
@code{c-electric-backspace} but in the forward direction.  When it
doesn't do an ``electric'' deletion of the following whitespace, it
calls the function in @code{c-delete-function} with its prefix
argument.
@end deffn

@defvar c-delete-function
@vindex delete-function (c-)
@findex delete-char
Hook that gets called by @code{c-electric-delete-forward} when it
doesn't do an ``electric'' deletion of the following whitespace.  The
default value is @code{delete-char}.
@end defvar

Above we have only talked about the @kbd{DEL} and @kbd{C-d} key events,
without connecting them to the physical keys commonly known as
@key{Backspace} and @key{Delete}.  The default behavior of those two
depends on the flavor of (X)Emacs you are using.

@findex c-electric-delete
@findex electric-delete (c-)
@vindex delete-key-deletes-forward

In XEmacs 20.3 and beyond, the @key{Backspace} key is bound to
@code{c-electric-backspace} and the @key{Delete} key is bound to
@code{c-electric-delete}.  You control the direction it deletes in by
setting the variable @code{delete-key-deletes-forward}, a standard
XEmacs variable.  When this variable is non-@code{nil},
@code{c-electric-delete} will do forward deletion with
@code{c-electric-delete-forward}, otherwise it does backward deletion
with @code{c-electric-backspace}.

In other Emacs versions, @ccmode{} doesn't bind either @key{Backspace}
or @key{Delete}.  In XEmacs 19 and Emacs prior to 21 that means that
it's up to you to fix them.  Emacs 21 automatically binds them as
appropriate to @kbd{DEL} and @kbd{C-d}.

Another way to use hungry deletion is to bind
@code{c-hungry-backspace} and @code{c-hungry-delete-forward} directly
to keys, and not use the mode toggling.  For example @kbd{C-c C-d} and
@kbd{C-c DEL} to match plain @kbd{C-d} and @kbd{DEL},

@example
(add-hook
 'c-mode-common-hook
 (lambda ()
   (define-key c-mode-base-map
               [?\C-c ?\d] 'c-hungry-backspace)
   (define-key c-mode-base-map
               [?\C-c ?\C-d] 'c-hungry-delete-forward)))
@end example

@deffn Command c-hungry-backspace
@findex hungry-backspace (c-)
Delete any amount of whitespace in the backwards direction (regardless
whether hungry-delete mode is enabled or not).
@end deffn

@deffn Command c-hungry-delete-forward
@findex hungry-delete-forward (c-)
Delete any amount of whitespace in the forward direction (regardless
whether hungry-delete mode is enabled or not).
@end deffn


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Text Filling and Line Breaking, Macro Handling, Minor Modes, Top
@comment node-name, next, previous, up
@chapter Text Filling and Line Breaking
@cindex text filling
@cindex line breaking
@cindex comment handling
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Since there's a lot of normal text in comments and string literals,
@ccmode{} provides features to edit these like in text mode.  The goal
is to do it as seamlessly as possible, i.e. you can use auto fill mode,
sentence and paragraph movement, paragraph filling, adaptive filling etc
wherever there's a piece of normal text without having to think much
about it.  @ccmode{} should keep the indentation, fix the comment line
decorations, and so on, for you.  It does that by hooking in on the
different line breaking functions and tuning relevant variables as
necessary.

@vindex c-comment-prefix-regexp
@vindex comment-prefix-regexp (c-)
@cindex comment line prefix
@vindex comment-start
@vindex comment-end
@vindex comment-start-skip
@vindex paragraph-start
@vindex paragraph-separate
@vindex paragraph-ignore-fill-prefix
@vindex adaptive-fill-mode
@vindex adaptive-fill-regexp
@vindex adaptive-fill-first-line-regexp
To make Emacs recognize comments and treat text in them as normal
paragraphs, @ccmode{} makes several standard
variables@footnote{@code{comment-start}, @code{comment-end},
@code{comment-start-skip}, @code{paragraph-start},
@code{paragraph-separate}, @code{paragraph-ignore-fill-prefix},
@code{adaptive-fill-mode}, @code{adaptive-fill-regexp}, and
@code{adaptive-fill-first-line-regexp}.} buffer local and modifies them
according to the language syntax and the comment line prefix.

@defopt c-comment-prefix-regexp
@vindex comment-prefix-regexp (c-)
This style variable contains the regexp used to recognize the
@dfn{comment line prefix}, which is the line decoration that starts
every line in a comment.  The default is @samp{//+\\|\\**}, which
matches C++ style line comments like

@example
// blah blah
@end example

@noindent
with two or more slashes in front of them, and C style block comments
like

@example
@group
/*
 * blah blah
 */
@end group
@end example

@noindent
with zero or more stars at the beginning of every line.  If you change
this variable, please make sure it still matches the comment starter
(i.e. @code{//}) of line comments @emph{and} the line prefix inside
block comments.

@findex c-setup-paragraph-variables
@findex setup-paragraph-variables (c-)
Also note that since @ccmode{} uses the value of
@code{c-comment-prefix-regexp} to set up several other variables at mode
initialization, there won't have any effect if you change it inside a
@ccmode{} buffer.  You need to call the command
@code{c-setup-paragraph-variables} to update those other variables with
the new value.  That's also the case if you modify this variable in a
mode hook, since @ccmode{} sets up all variables before calling them.
@end defopt

@findex auto-fill-mode
@cindex Auto Fill mode
@cindex paragraph filling
Line breaks are by default handled (almost) the same regardless whether
they are made by auto fill mode (@pxref{Auto Fill,,, emacs, The Emacs
Editor}), paragraph filling (e.g. with @kbd{M-q}), or explicitly with
@kbd{M-j} or similar methods.  In string literals, the new line gets the
same indentation as the previous nonempty line (may be changed with the
@code{string} syntactic symbol).  In comments, @ccmode{} uses
@code{c-comment-prefix-regexp} to adapt the line prefix from the other
lines in the comment.

@vindex adaptive-fill-mode
@cindex Adaptive Fill mode
@ccmode{} uses adaptive fill mode (@pxref{Adaptive Fill,,, emacs, The
Emacs Editor}) to make Emacs correctly keep the line prefix when filling
paragraphs.  That also makes Emacs preserve the text indentation
@emph{inside} the comment line prefix.  E.g. in the following comment,
both paragraphs will be filled with the left margins of the texts kept
intact:

@example
@group
/* Make a balanced b-tree of the nodes in the incoming
 * stream.  But, to quote the famous words of Donald E.
 * Knuth,
 *
 *     Beware of bugs in the above code; I have only
 *     proved it correct, not tried it.
 */
@end group
@end example

@findex c-setup-filladapt
@findex setup-filladapt (c-)
@findex filladapt-mode
@vindex filladapt-mode
@cindex Filladapt mode
It's also possible to use other adaptive filling packages, notably Kyle
E. Jones' Filladapt package@footnote{It's available from
@uref{http://www.wonderworks.com/}.  As of version 2.12, it does however
lack a feature that makes it work suboptimally when
@code{c-comment-prefix-regexp} matches the empty string (which it does
by default).  A patch for that is available from
@uref{http://cc-mode.sourceforge.net/,, the CC Mode web site}.},
which handles things like bulleted lists nicely.  There's a convenience
function @code{c-setup-filladapt} that tunes the relevant variables in
Filladapt for use in @ccmode{}.  Call it from a mode hook, e.g. with
something like this in your @file{.emacs}:

@example
(defun my-c-mode-common-hook ()
  (c-setup-filladapt)
  (filladapt-mode 1))
(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
@end example

@defopt c-block-comment-prefix
@vindex block-comment-prefix (c-)
@vindex c-comment-continuation-stars
@vindex comment-continuation-stars (c-)
Normally the comment line prefix inserted for a new line inside a
comment is deduced from other lines in it.  However there's one
situation when there's no hint about what the prefix should look like,
namely when a block comment is broken for the first time.  This style
variable@footnote{In versions before 5.26, this variable was called
@code{c-comment-continuation-stars}.  As a compatibility measure,
@ccmode{} still uses the value on that variable if it's set.} is used
then as the comment prefix.  It defaults to @samp{* }, which makes a
comment

@example
/* Got O(n^2) here, which is a Bad Thing. */
@end example

@noindent
break into

@example
@group
/* Got O(n^2) here,
 * which is a Bad Thing. */
@end group
@end example

Note that it won't work to adjust the indentation by putting leading
spaces in @code{c-block-comment-prefix}, since @ccmode{} still uses the
normal indentation engine to indent the line.  Thus, the right way to
fix the indentation is by customizing the @code{c} syntactic symbol.  It
defaults to @code{c-lineup-C-comments}, which handles the indentation of
most common comment styles, see @ref{Indentation Functions}.
@end defopt

@defopt c-ignore-auto-fill
@vindex ignore-auto-fill (c-)
When auto fill mode is enabled, @ccmode{} can selectively ignore it
depending on the context the line break would occur in, e.g. to never
break a line automatically inside a string literal.  This variable
takes a list of symbols for the different contexts where auto-filling
never should occur:

@table @code
@item string
Inside a string or character literal.
@item c
Inside a C style block comment.
@item c++
Inside a C++ style line comment.
@item cpp
Inside a preprocessor directive.
@item code
Anywhere else, i.e. in normal code.
@end table

By default, @code{c-ignore-auto-fill} is set to @code{'(string cpp
code)}, which means that auto-filling only occurs in comments when
auto-fill mode is activated.  In literals, it's often desirable to have
explicit control over newlines.  In preprocessor directives, the
necessary @samp{\} escape character before the newline is not
automatically inserted, so an automatic line break would produce invalid
code.  In normal code, line breaks are normally dictated by some logical
structure in the code rather than the last whitespace character, so
automatic line breaks there will produce poor results in the current
implementation.
@end defopt

The commands that do the actual work follow.

@table @asis
@item @kbd{M-q} (@code{c-fill-paragraph})
@kindex M-q
@findex c-fill-paragraph
@findex fill-paragraph (c-)
@cindex Javadoc markup
@cindex Pike autodoc markup
This is the replacement for @code{fill-paragraph} in @ccmode{}
buffers. It's used to fill multiline string literals and both block and
line style comments.  In Java buffers, the Javadoc markup words are
recognized as paragraph starters.  The line oriented Pike autodoc markup
words are recognized in the same way in Pike mode.

The function keeps the comment starters and enders of block comments as
they were before the filling.  This means that a comment ender on the
same line as the paragraph being filled will be filled with the
paragraph, and one on a line by itself will stay as it is.  The comment
starter is handled similarly@footnote{This means that the variables
@code{c-hanging-comment-starter-p} and @code{c-hanging-comment-ender-p},
which controlled this behavior in earlier versions of @ccmode{}, are now
obsolete.}.

@item @kbd{M-j} (@code{c-indent-new-comment-line})
@kindex M-j
@findex c-indent-new-comment-line
@findex indent-new-comment-line (c-)
This is the replacement for @code{indent-new-comment-line}.  It breaks
the line at point and indents the new line like the current one.

@vindex comment-multi-line
If inside a comment and @code{comment-multi-line} is non-@code{nil}, the
indentation and line prefix are preserved.  If inside a comment and
@code{comment-multi-line} is @code{nil}, a new comment of the same type
is started on the next line and indented as appropriate for comments.

Note that @ccmode{} sets @code{comment-multi-line} to @code{t} at
startup.  The reason is that @kbd{M-j} could otherwise produce sequences
of single line block comments for texts that should logically be treated
as one comment, and the rest of the paragraph handling code
(e.g. @kbd{M-q} and @kbd{M-a}) can't cope with that, which would lead to
inconsistent behavior.

@item @kbd{M-x c-context-line-break}
@findex c-context-line-break
@findex context-line-break (c-)
This is a function that works like @code{indent-new-comment-line} in
comments and @code{newline-and-indent} elsewhere, thus combining those
two in a way that uses each one in the context it's best suited for.
I.e. in comments the comment line prefix and indentation is kept for
the new line, and in normal code it's indented according to context by
the indentation engine.

In macros it acts like @code{newline-and-indent} but additionally
inserts and optionally aligns the line ending backslash so that the
macro remains unbroken.  @xref{Macro Handling}, for details about the
backslash alignment.

It's not bound to a key by default, but it's intended to be used on the
@kbd{RET} key.  If you like the behavior of @code{newline-and-indent} on
@kbd{RET}, you should consider switching to this function.

@item @kbd{M-x c-context-open-line}
@findex c-context-open-line
@findex context-open-line (c-)
This is to @kbd{C-o} (@kbd{M-x open-line}) as
@code{c-context-line-break} is to @kbd{RET}.  I.e. it works just like
@code{c-context-line-break} but leaves the point before the inserted
line break.
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Macro Handling, Font Locking, Text Filling and Line Breaking, Top
@comment node-name, next, previous, up
@chapter Macro Handling
@cindex macros
@cindex preprocessor directives
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Preprocessor directives are handled as syntactic whitespace from other
code, i.e. they can be interspersed anywhere without affecting the
syntactic analysis, just like comments.

The code inside macro definitions is still analyzed syntactically so
that you get relative indentation there just as you'd get if the same
code was outside a macro.  However, since there is no hint about the
syntactic context, i.e. whether the macro expands to an expression, to some
statements, or perhaps to whole functions, the syntactic recognition can be
wrong.  @ccmode{} manages to figure it out correctly most of the time,
though.  @xref{Syntactic Symbols}, for details about the indentation.

@defopt c-syntactic-indentation-in-macros
@vindex syntactic-indentation-in-macros (c-)
Enable syntactic analysis inside macros, which is the default.  If this
is @code{nil}, all lines inside macro definitions are analyzed as
@code{cpp-macro-cont}.
@end defopt

@ccmode{} provides some tools to help keep the line continuation
backslashes in macros neat and tidy:

@table @asis
@item @kbd{C-c C-\} (@code{c-backslash-region})
@kindex C-c C-\
@findex c-backslash-region
@findex backslash-region (c-)
This function inserts and aligns or deletes the end-of-line backslashes
in the current region.

With no prefix argument, it inserts any missing backslashes and aligns
them according to the @code{c-backslash-column} and
@code{c-backslash-max-column} variables.  With a prefix argument, it
deletes any backslashes.

The function does not modify blank lines at the start of the region.  If
the region ends at the start of a line, it always deletes the backslash
(if any) at the end of the previous line.
@end table

@defopt c-backslash-column
@vindex backslash-column (c-)
@defoptx c-backslash-max-column
@vindex backslash-max-column (c-)
These variables control the alignment columns for line continuation
backslashes in multiline macros.  They are used by the functions that
automatically insert or align such backslashes,
e.g. @code{c-backslash-region} and @code{c-context-line-break}.

@code{c-backslash-column} specifies the minimum column for the
backslashes.  If any line in the macro exceeds it then the next tab
stop from that line is used as the alignment column for all the
backslashes, so that they remain in a single column.  However, if some
lines exceed @code{c-backslash-max-column} then the backslashes in the
rest of the macro will be kept at that column, so that the
lines which are too long ``stick out'' instead.
@end defopt

@defopt c-auto-align-backslashes
@vindex auto-align-backslashes (c-)
Align automatically inserted line continuation backslashes if
non-@code{nil}.  When line continuation backslashes are inserted
automatically for line breaks in multiline macros, e.g. by
@code{c-context-line-break}, they are aligned with the other backslashes
in the same macro if this flag is set.  Otherwise the inserted
backslashes are preceded by a single space.
@end defopt

The recommended line breaking function, @code{c-context-line-break}
(@pxref{Text Filling and Line Breaking}), is especially nice if you edit
multiline macros frequently.  When used inside a macro, it automatically
inserts and adjusts the mandatory backslash at the end of the line to
keep the macro together, and it leaves the point at the right
indentation column for the code.  Thus you can write code inside macros
almost exactly as you can elsewhere, without having to bother with the
trailing backslashes.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Font Locking, Commands, Macro Handling, Top
@comment node-name, next, previous, up
@chapter Font Locking
@cindex font locking
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@strong{Note:} The font locking in AWK mode is currently not integrated
with the rest of @ccmode{}, so this section does not apply there.
@xref{AWK Mode Font Locking}, instead.

@cindex Font Lock mode

@ccmode{} provides font locking for its supported languages by supplying
patterns for use with Font Lock mode.  This means that you get distinct
faces on the various syntactic parts such as comments, strings, keywords
and types, which is very helpful in telling them apart at a glance and
discovering syntactic errors.  @xref{Font Lock,,, emacs, The Emacs
Editor}, for ways to enable font locking in @ccmode{} buffers.

@menu
* Font Locking Preliminaries::
* Faces::
* Documentation Comments::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Font Locking Preliminaries, Faces, , Font Locking
@comment node-name, next, previous, up
@section Font Locking Preliminaries
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The font locking for most of the @ccmode{} languages were provided
directly by the Font Lock package prior to version 5.30 of @ccmode{}.
In the transition to @ccmode{} the patterns have been reworked
completely and are applied uniformly across all the languages except AWK
mode, just like the indentation rules (although each language still has
some pecularities of its own, of course).  Since the languages
previously had completely separate font locking patterns, this means
that it's a bit different in most languages now.

The main goal for the font locking in @ccmode{} is accuracy, to provide
a dependable aid in recognizing the various constructs.  Some, like
strings and comments, are easy to recognize while others like
declarations and types can be very tricky.  @ccmode{} can go to great
lengths to recognize declarations and casts correctly, especially when
the types aren't recognized by standard patterns.  This is a fairly
demanding analysis which can be slow on older hardware, and it can
therefore be disabled by choosing a lower decoration level with the
variable @code{font-lock-maximum-decoration}.

@vindex font-lock-maximum-decoration

The decoration levels are used as follows:

@enumerate
@comment 1
@item
Minimal font locking: Fontify only comments, strings and preprocessor
directives (in the languages that use cpp).

@comment 2
@item
Fast normal font locking: In addition to level 1, fontify keywords,
simple types and declarations that are easy to recognize.  The variables
@code{*-font-lock-extra-types} (where @samp{*} is the name of the
language) are used to recognize types (see below).  Documentation
comments like Javadoc are fontified according to
@code{c-doc-comment-style} (@pxref{Documentation Comments}).

Use this if you think the font locking is too slow.  It's the closest
corresponding level to level 3 in the old font lock patterns.

@comment 3
@item
Accurate normal font locking: Like level 2 but uses a different approach
that can recognize types and declarations much more accurately.  The
@code{*-font-lock-extra-types} variables are still used, but user
defined types are recognized correctly anyway in most cases.  Therefore
those variables should be fairly restrictive and not contain patterns
that are uncertain.

@cindex Lazy Lock mode
@cindex Just-in-time Lock mode

This level is designed for fairly modern hardware and a font lock
support mode like Lazy Lock or Just-in-time Lock mode that only
fontifies the parts that are actually shown.
@end enumerate

@cindex user defined types
@cindex types, user defined

Since user defined types are hard to recognize you can provide
additional regexps to match those you use:

@defopt c-font-lock-extra-types
@defoptx c++-font-lock-extra-types
@defoptx objc-font-lock-extra-types
@defoptx java-font-lock-extra-types
@defoptx idl-font-lock-extra-types
@defoptx pike-font-lock-extra-types
For each language there's a variable @code{*-font-lock-extra-types},
where @samp{*} stands for the language in question.  It contains a list
of regexps that matches identifiers that should be recognized as types,
e.g. @samp{\\sw+_t} to recognize all identifiers ending with @samp{_t}
as is customary in C code.  Each regexp should not match more than a
single identifier.

The default values contain regexps for many types in standard runtime
libraries that are otherwise difficult to recognize, and patterns for
standard type naming conventions like the @samp{_t} suffix in C and C++.
Java, Objective-C and Pike have as a convention to start class names
with capitals, so there are patterns for that in those languages.

Despite the names of these variables, they are not only used for
fontification but in other places as well where @ccmode{} needs to
recognize types.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Faces, Documentation Comments, Font Locking Preliminaries, Font Locking
@comment node-name, next, previous, up
@section Faces
@cindex faces
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} attempts to use the standard faces for programming languages
in accordance with their intended purposes as far as possible.  No extra
faces are currently provided, with the exception of a replacement face
@code{c-invalid-face} for emacsen that don't provide
@code{font-lock-warning-face}.

@itemize @bullet
@item
@vindex font-lock-comment-face
Normal comments are fontified in @code{font-lock-comment-face}.

@item
@vindex font-lock-doc-face
@vindex font-lock-doc-string-face
@vindex font-lock-comment-face
Comments that are recognized as documentation (@pxref{Documentation
Comments}) get @code{font-lock-doc-face} (Emacs) or
@code{font-lock-doc-string-face} (XEmacs) if those faces exist.  If they
don't then @code{font-lock-comment-face} is used.

@item
@vindex font-lock-string-face
String and character literals are fontified in
@code{font-lock-string-face}.

@item
@vindex font-lock-keyword-face
Keywords are fontified with @code{font-lock-keyword-face}.

@item
@vindex font-lock-function-name-face
@code{font-lock-function-name-face} is used for function names in
declarations and definitions, and classes in those contexts.  It's also
used for preprocessor defines with arguments.

@item
@vindex font-lock-variable-name-face
Variables in declarations and definitions, and other identifiers in such
variable contexts, get @code{font-lock-variable-name-face}.  It's also
used for preprocessor defines without arguments.

@item
@vindex font-lock-constant-face
@vindex font-lock-reference-face
Builtin constants are fontified in @code{font-lock-constant-face} if it
exists, @code{font-lock-reference-face} otherwise.  As opposed to the
preceding two faces, this is used on the names in expressions, and it's
not used in declarations, even if there happen to be a @samp{const} in
them somewhere.

@item
@vindex font-lock-type-face
@code{font-lock-type-face} is put on types (both predefined and user
defined) and classes in type contexts.

@item
@vindex font-lock-constant-face
@vindex font-lock-reference-face
Label identifiers get @code{font-lock-constant-face} if it exists,
@code{font-lock-reference-face} otherwise.

@item
Name qualifiers and identifiers for scope constructs are fontified like
labels.

@item
Special markup inside documentation comments are also fontified like
labels.

@item
@vindex font-lock-preprocessor-face
@vindex font-lock-builtin-face
@vindex font-lock-reference-face
Preprocessor directives get @code{font-lock-preprocessor-face} if it
exists (i.e. XEmacs).  In Emacs they get @code{font-lock-builtin-face}
or @code{font-lock-reference-face}, for lack of a closer equivalent.

@item
@vindex font-lock-warning-face
@vindex c-invalid-face
@vindex invalid-face (c-)
Some kinds of syntactic errors are fontified with
@code{font-lock-warning-face} in Emacs.  In older XEmacs versions
there's no corresponding standard face, so there a special
@code{c-invalid-face} is used, which is defined to stand out sharply by
default.

Note that it's not used for @samp{#error} or @samp{#warning} directives,
since those aren't syntactic errors in themselves.
@end itemize


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Documentation Comments, , Faces, Font Locking
@comment node-name, next, previous, up
@section Documentation Comments
@cindex documentation comments
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

There are various tools to supply documentation in the source as
specially structured comments, e.g. the standard Javadoc tool in Java.
@ccmode{} provides an extensible mechanism to fontify such comments and
the special markup inside them.

@defopt c-doc-comment-style
@vindex doc-comment-style (c-)
This is a style variable that specifies which documentation comment
style to recognize, e.g. @code{javadoc} for Javadoc comments.

The value may also be a list of styles, in which case all of them are
recognized simultaneously (presumably with markup cues that don't
conflict).

The value may also be an association list to specify different comment
styles for different languages.  The symbol for the major mode is then
looked up in the alist, and the value of that element is interpreted as
above if found.  If it isn't found then the symbol `other' is looked up
and its value is used instead.

Note that @ccmode{} uses this variable to set other variables that
handle fontification etc.  That's done at mode initialization or when
you switch to a style which sets this variable.  Thus, if you change it
in some other way, e.g. interactively in a CC Mode buffer, you will need
to do @kbd{M-x java-mode} (or whatever mode you're currently using) to
reinitialize.

@findex c-setup-doc-comment-style
@findex setup-doc-comment-style (c-)
Note also that when @ccmode{} starts up, the other variables are
modified before the mode hooks are run.  If you change this variable in
a mode hook, you have to call @code{c-setup-doc-comment-style}
afterwards to redo that work.
@end defopt

@ccmode{} currently provides handing of the following doc comment
styles:

@table @code
@item javadoc
@cindex Javadoc markup
Javadoc comments, the standard tool in Java.

@item autodoc
@cindex Pike autodoc markup
For Pike autodoc markup, the standard in Pike.
@end table

The above is by no means complete.  If you'd like to see support for
other doc comment styles, please let us know (@pxref{Mailing Lists and
Submitting Bug Reports}).

You can also write your own doc comment fontification support to use
with @code{c-doc-comment-style}: Supply a variable or function
@code{*-font-lock-keywords} where @samp{*} is the name you want to use
in @code{c-doc-comment-style}.  If it's a variable, it's prepended to
@code{font-lock-keywords}.  If it's a function, it's called at mode
initialization and the result is prepended.  For an example, see
@code{javadoc-font-lock-keywords} in @file{cc-fonts.el}.

If you add support for another doc comment style, please consider
contributing it --- send a note to @email{bug-cc-mode@@gnu.org}.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Commands, Customizing Indentation, Font Locking, Top
@comment node-name, next, previous, up
@chapter Commands
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@menu
* Indentation Commands::
* Movement Commands::
* Other Commands::
@end menu

See also @ref{Text Filling and Line Breaking} and @ref{Macro Handling},
for commands concerning those bits.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Indentation Commands, Movement Commands, , Commands
@comment node-name, next, previous,up
@section Indentation Commands
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The following list of commands reindent C constructs.  Note that when
you change your coding style, either interactively or through some other 
means, your file does @emph{not} automatically get reindented.  You
will need to execute one of the following commands to see the effects of 
your changes.

@cindex GNU indent program
Also, variables like @code{c-hanging-*} and @code{c-cleanup-list}
only affect how on-the-fly code is formatted.  Changing the
``hanginess'' of a brace and then reindenting, will not move the brace
to a different line.  For this, you're better off getting an external
program like GNU @code{indent}, which will rearrange brace location,
among other things.

Reindenting large sections of code can take a long time.  When
@ccmode{} reindents a region of code, it is essentially equivalent to
hitting @kbd{TAB} on every line of the region.

These commands are useful when indenting code:

@table @asis
@item @kbd{TAB} (@code{c-indent-command})
@kindex TAB
@findex c-indent-command
@findex indent-command (c-)
Indents the current line.  The actual behavior is controlled by several
variables, described below.  See @code{c-tab-always-indent},
@code{c-insert-tab-function}, and @code{indent-tabs-mode}.  With a
numeric argument, this command rigidly indents the region, preserving
the relative indentation among the lines.

@item @kbd{C-M-q} (@code{c-indent-exp})
@kindex C-M-q
@findex c-indent-exp
@findex indent-exp (c-)
Indent an entire balanced brace or parenthesis expression.  Note that
point must be on the opening brace or parenthesis of the expression you
want to indent.

@item @kbd{C-c C-q} (@code{c-indent-defun})
@kindex C-c C-q
@findex c-indent-defun
@findex indent-defun (c-)
Indents the entire top-level function, class or macro definition
encompassing point.  It leaves point unchanged.  This function can't be
used to reindent a nested brace construct, such as a nested class or
function, or a Java method.  The top-level construct being reindented
must be complete, i.e. it must have both a beginning brace and an ending
brace.

@item @kbd{C-M-\} (@code{indent-region})
@kindex C-M-\
@findex indent-region
Indents an arbitrary region of code.  This is a standard Emacs command,
tailored for C code in a @ccmode{} buffer.  Note, of course, that point
and mark must delineate the region you want to indent.

@item @kbd{M-;} (@code{indent-for-comment})
@kindex M-;
@findex indent-for-comment
Insert a comment at the end of the current line, if none is there already.
Then reindent the comment according to the variables
@code{c-indent-comment-alist}, @code{c-indent-comments-syntactically-p}
and @code{comment-column}.  Then position the point after the comment
starter.  This is a standard Emacs command, but @ccmode{} enhances it a
bit with two variables:

@defopt c-indent-comment-alist
@vindex indent-comment-alist (c-)
@vindex comment-column
This style variable allows you to control which column @kbd{M-;}
indents the comment to, depending on the preceding code and the
indentation of a similar comment on the preceding line, if there is
any.  It is an association list that maps different types of lines to
actions describing how they should be handled.  If a certain line type
isn't present on the list then the line is indented to the column
specified by @code{comment-column}.  See the documentation string for
@code{c-indent-comment-alist} for a full description of the available
line types and actions (use @kbd{C-h v c-indent-comment-alist}).
@end defopt

@defopt c-indent-comments-syntactically-p
@vindex indent-comments-syntactically-p (c-)
Normally, when this variable is @code{nil}, @kbd{M-;} will indent
comment-only lines according to @code{c-indent-comment-alist}, just as
it does with lines where other code precede the comments.  However, if
you want it to act just like @kbd{TAB} for comment-only lines you can
get that by setting @code{c-indent-comments-syntactically-p} to
non-@code{nil}.

If @code{c-indent-comments-syntactically-p} is non-@code{nil} then
@code{c-indent-comment-alist} won't be consulted at all for comment-only
lines.
@end defopt

@item @kbd{C-M-h} (@code{c-mark-function})
@kindex C-M-h
@findex c-mark-function
@findex mark-function (c-)
While not strictly an indentation command, this is useful for marking
the current top-level function or class definition as the current
region.  As with @code{c-indent-defun}, this command operates on
top-level constructs, and can't be used to mark say, a Java method.
@end table

These variables are also useful when indenting code:

@defopt c-tab-always-indent
@vindex tab-always-indent (c-)
@kindex TAB
@cindex literal
This variable controls how @kbd{TAB} (@code{c-indent-command}) operates.
When it is @code{t}, @kbd{TAB} always indents the current line.  When it
is @code{nil}, the line is indented only if point is at the left margin,
or on or before the first non-whitespace character on the line,
otherwise some whitespace is inserted.  If this variable is the symbol
@code{other}, then some whitespace is inserted only within strings and
comments (literals), and inside preprocessor directives, but the line is
always reindented.
@end defopt

@defopt c-insert-tab-function
@vindex insert-tab-function (c-)
@findex tab-to-tab-stop
When ``some whitespace'' is inserted as described above, what actually
happens is that the function stored in @code{c-insert-tab-function} is
called.  Normally, this just inserts a real tab character, or the
equivalent number of spaces, depending on @code{indent-tabs-mode}.
Some people, however, set @code{c-insert-tab-function} to
@code{tab-to-tab-stop} so as to get hard tab stops when indenting.
@end defopt

@defopt indent-tabs-mode
This is a standard Emacs variable that controls how line indentation
is composed.  When it's non-@code{nil}, tabs can be used in a line's
indentation, otherwise only spaces can be used.
@end defopt

@defopt c-progress-interval
@vindex progress-interval (c-)
When indenting large regions of code, this variable controls how often a
progress message is displayed.  Set this variable to @code{nil} to
inhibit the progress messages, or set it to an integer which is how
often (in seconds) progress messages are to be displayed.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Movement Commands, Other Commands, Indentation Commands, Commands
@comment node-name, next, previous, up
@section Movement Commands
@cindex movement
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} contains some useful commands for moving around in C
code.

@table @asis
@item @kbd{M-x c-beginning-of-defun}
@findex c-beginning-of-defun
@findex beginning-of-defun (c-)
@findex beginning-of-defun
Move point back to the least-enclosing brace.  This function is
analogous to the Emacs built-in command @code{beginning-of-defun},
except it eliminates the constraint that the top-level opening brace
must be in column zero.  See @code{beginning-of-defun} for more
information.

Depending on the coding style being used, you might prefer
@code{c-beginning-of-defun} to @code{beginning-of-defun}.  If so,
consider binding @kbd{C-M-a} to the former instead.  For backwards
compatibility reasons, the default binding remains in effect.

In AWK mode, a defun doesn't necessarily have braces at all.  AWK Mode
therefore has its own version of this function which is bound by
default to @kbd{C-M-a}.  You can thus chose freely which function to
bind to @kbd{C-M-a} for the other modes without worrying about AWK
buffers.  @xref{AWK Mode Defuns}.

@item @kbd{M-x c-end-of-defun}
@findex c-end-of-defun
@findex end-of-defun (c-)
@findex end-of-defun
Moves point to the end of the current top-level definition.  This
function is analogous to the Emacs built-in command @code{end-of-defun},
except it eliminates the constraint that the top-level opening brace of
the defun must be in column zero.  See @code{end-of-defun} for more
information.

Depending on the coding style being used, you might prefer
@code{c-end-of-defun} to @code{end-of-defun}.  If so,
consider binding @kbd{C-M-e} to the former instead.  For backwards
compatibility reasons, the default binding remains in effect.

In AWK Mode, a defun doesn't necessarily have braces at all.  AWK Mode
therefore has its own version of this function which is bound by
default to @kbd{C-M-e}.  You can thus chose freely which function to
bind to @kbd{C-M-e} for the other modes without worrying about AWK
buffers.  @ref{AWK Mode Defuns}.

@item @kbd{C-c C-u} (@code{c-up-conditional})
@kindex C-c C-u
@findex c-up-conditional
@findex up-conditional (c-)
Move point back to the containing preprocessor conditional, leaving the
mark behind.  A prefix argument acts as a repeat count.  With a negative
argument, move point forward to the end of the containing
preprocessor conditional.

@samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
function stops at them when going backward, but not when going forward.

@item @kbd{M-x c-up-conditional-with-else}
@findex c-up-conditional-with-else
@findex up-conditional-with-else (c-)
A variety of @code{c-up-conditional} that also stops at @samp{#else}
lines.  Normally those lines are ignored.

@item @kbd{M-x c-down-conditional}
@findex c-down-conditional
@findex down-conditional (c-)
Move point forward into the next nested preprocessor conditional,
leaving the mark behind.  A prefix argument acts as a repeat count.
With a negative argument, move point backward into the previous
nested preprocessor conditional.

@samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
function stops at them when going forward, but not when going backward.

@item @kbd{M-x c-down-conditional-with-else}
@findex c-down-conditional-with-else
@findex down-conditional-with-else (c-)
A variety of @code{c-down-conditional} that also stops at @samp{#else}
lines.  Normally those lines are ignored.

@item @kbd{C-c C-p} (@code{c-backward-conditional})
@kindex C-c C-p
@findex c-backward-conditional
@findex backward-conditional (c-)
Move point back over a preprocessor conditional, leaving the mark
behind.  A prefix argument acts as a repeat count.  With a negative
argument, move forward.

@item @kbd{C-c C-n} (@code{c-forward-conditional})
@kindex C-c C-n
@findex c-forward-conditional
@findex forward-conditional (c-)
Move point forward across a preprocessor conditional, leaving the mark
behind.  A prefix argument acts as a repeat count.  With a negative
argument, move backward.

@item @kbd{M-a} (@code{c-beginning-of-statement})
@kindex M-a
@findex c-beginning-of-statement
@findex beginning-of-statement (c-)
Move point to the beginning of the innermost C statement.  If point is
already at the beginning of a statement, move to the beginning of the
closest preceding statement, even if that means moving into a block (you
can use @kbd{C-M-b} to move over a balanced block).  With prefix
argument @var{n}, move back @var{n} @minus{} 1 statements.

If point is within or next to a comment or a string which spans more
than one line, this command moves by sentences instead of statements.

When called from a program, this function takes three optional
arguments: the repetition count, a buffer position limit which is the
farthest back to search for the syntactic context, and a flag saying
whether to do sentence motion in or near comments and multiline strings.

@item @kbd{M-e} (@code{c-end-of-statement})
@kindex M-e
@findex c-end-of-statement
@findex end-of-statement (c-)
Move point to the end of the innermost C statement.  If point is at the
end of a statement, move to the end of the next statement, even if it's
inside a nested block (use @kbd{C-M-f} to move to the other side of the
block).  With prefix argument @var{n}, move forward @var{n} @minus{} 1
statements.

If point is within or next to a comment or a string which spans more
than one line, this command moves by sentences instead of statements.

When called from a program, this function takes three optional
arguments: the repetition count, a buffer position limit which is the
farthest back to search for the syntactic context, and a flag saying
whether to do sentence motion in or near comments and multiline strings.

@item @kbd{M-x c-forward-into-nomenclature}
@findex c-forward-into-nomenclature
@findex forward-into-nomenclature (c-)
A popular programming style, especially for object-oriented languages
such as C++ is to write symbols in a mixed case format, where the first
letter of each word is capitalized, and not separated by underscores.
E.g. @samp{SymbolsWithMixedCaseAndNoUnderlines}.

This command moves point forward to next capitalized word.  With prefix
argument @var{n}, move @var{n} times.

@item @kbd{M-x c-backward-into-nomenclature}
@findex c-backward-into-nomenclature
@findex backward-into-nomenclature (c-)
Move point backward to beginning of the next capitalized
word.  With prefix argument @var{n}, move @var{n} times.  If
@var{n} is negative, move forward.
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Other Commands, , Movement Commands, Commands
@comment node-name, next, previous, up
@section Other Commands
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Here are the various other commands that didn't fit anywhere else:

@table @asis
@item @kbd{C-c :} (@code{c-scope-operator})
@kindex C-c :
@findex c-scope-operator
@findex scope-operator (c-)
In C++, it is also sometimes desirable to insert the double-colon scope
operator without performing the electric behavior of colon insertion.
@kbd{C-c :} does just this.
@end table

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Customizing Indentation, Syntactic Symbols, Commands, Top
@comment node-name, next, previous, up
@chapter Customizing Indentation
@cindex customization, indentation
@cindex indentation
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The context sensitive indentation is mainly controlled by the variable
@code{c-offsets-alist}:

@defopt c-offsets-alist
@vindex offsets-alist (c-)
This special style variable contains the mappings between syntactic
symbols and the offsets to apply for those symbols.  It's set at mode
initialization from a @emph{style} you may specify.  Styles are
groupings of syntactic symbol offsets and other style variable values.
Most likely, you'll find that one of the predefined styles will suit
your needs.  @xref{Styles}, for an explanation of how to set up named
styles.

Only syntactic symbols not already bound on @code{c-offsets-alist} will
be set from styles.  This means that any association you set on it, be
it before or after mode initialization, will not be changed.  The
@code{c-offsets-alist} variable may therefore be used from e.g. the
Customization interface@footnote{Available in Emacs 20 and later, and
XEmacs 19.15 and later.} to easily change indentation offsets without
having to bother about styles.  Initially @code{c-offsets-alist} is
empty, so that all syntactic symbols are set by the style system.

The offset associated with any particular syntactic symbol can be an
integer, a function or lambda expression, a variable name, a vector, a
list, or one of the following special symbols: @code{+}, @code{-},
@code{++}, @code{--}, @code{*}, or @code{/}.  The meaning of these
values are described in detail below.
@end defopt

The special symbols describe an offset in multiples of the value of
@code{c-basic-offset}:

@defopt c-basic-offset
@vindex basic-offset (c-)
Style variable that holds the basic offset between indentation levels.
@end defopt

By defining a style's indentation in terms of @code{c-basic-offset},
you can change the amount of whitespace given to an indentation level
while maintaining the same basic shape of your code.  Here are the
values that the special symbols correspond to:

@table @code
@item +
@code{c-basic-offset} times 1
@item -
@code{c-basic-offset} times -1
@item ++
@code{c-basic-offset} times 2
@item --
@code{c-basic-offset} times -2
@item *
@code{c-basic-offset} times 0.5
@item /
@code{c-basic-offset} times -0.5
@end table

@cindex indentation functions

When a function is used as offset, it's called an @dfn{indentation
function}.  Such functions are useful when more context than just the
syntactic symbol is needed to get the desired indentation.
@xref{Indentation Functions}, and @ref{Custom Indentation Functions},
for details about them.

If the offset is a vector, its first element sets the absolute
indentation column, which will override any previous relative
indentation.  It won't override additional relative indentation for
nested constructs, though.

@vindex c-strict-syntax-p
@vindex strict-syntax-p (c-)
The offset can also be a list, in which case it is evaluated recursively
using the semantics described above.  The first element of the list that
returns a non-@code{nil} value succeeds and the evaluation stops.  If
none of the list elements return a non-@code{nil} value, then an offset
of 0 (zero) is used@footnote{There is however a variable
@code{c-strict-syntax-p} that, when set to non-@code{nil}, will cause an
error to be signalled in that case.  It's now considered obsolete since
it doesn't work well with some of the alignment functions that now
returns @code{nil} instead of zero to be more usable in lists.  You
should therefore leave @code{c-strict-syntax-p} set to @code{nil}.}.

So, for example, because most of the default offsets are defined in
terms of @code{+}, @code{-}, and @code{0}, if you like the general
indentation style, but you use 4 spaces instead of 2 spaces per level,
you can probably achieve your style just by changing
@code{c-basic-offset} like so@footnote{You can try this interactively in
a C buffer by typing the text that appears in italics.}:

@example
@emph{M-x set-variable RET}
Set variable: @emph{c-basic-offset RET}
Set c-basic-offset to value: @emph{4 RET}
@end example

@noindent
This would change

@example
@group
int add( int val, int incr, int doit )
@{
  if( doit )
    @{
      return( val + incr );
    @}
  return( val );
@}
@end group
@end example

@noindent
to

@example
@group
int add( int val, int incr, int doit )
@{
    if( doit )
        @{
            return( val + incr );
        @}
    return( val );
@}
@end group
@end example

To change indentation styles more radically, you will want to change the
offsets associated with other syntactic symbols.  First, I'll show you
how to do that interactively, then I'll describe how to make changes to
your @file{.emacs} file so that your changes are more permanent.

@menu
* Interactive Customization::
* Permanent Customization::
* Hooks::
* Styles::
* Advanced Customizations::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Interactive Customization, Permanent Customization, , Customizing Indentation
@comment node-name, next, previous, up
@section Interactive Customization
@cindex customization, interactive
@cindex interactive customization
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

As an example of how to customize indentation, let's change the
style of this example@footnote{In this and subsequent examples, the
original code is formatted using the @samp{gnu} style unless otherwise
indicated.  @xref{Styles}.}:

@example
@group
 1: int add( int val, int incr, int doit )
 2: @{
 3:   if( doit )
 4:     @{
 5:       return( val + incr );
 6:     @}
 7:   return( val );
 8: @}
@end group
@end example

@noindent
to:

@example
@group
 1: int add( int val, int incr, int doit )
 2: @{
 3:   if( doit )
 4:   @{
 5:     return( val + incr );
 6:   @}
 7:   return( val );
 8: @}
@end group
@end example

In other words, we want to change the indentation of braces that open a
block following a condition so that the braces line up under the
conditional, instead of being indented.  Notice that the construct we
want to change starts on line 4.  To change the indentation of a line,
we need to see which syntactic components affect the offset calculations
for that line.  Hitting @kbd{C-c C-s} on line 4 yields:

@example
((substatement-open 44))
@end example

@noindent
so we know that to change the offset of the open brace, we need to
change the indentation for the @code{substatement-open} syntactic
symbol.

To do this interactively, just hit @kbd{C-c C-o}.  This prompts
you for the syntactic symbol to change, providing a reasonable default.
In this case, the default is @code{substatement-open}, which is just the
syntactic symbol we want to change!

After you hit return, @ccmode{} will then prompt you for the new
offset value, with the old value as the default.  The default in this
case is @samp{+}, but we want no extra indentation so enter
@samp{0} and @kbd{RET}.  This will associate the offset 0 with the
syntactic symbol @code{substatement-open}.

To check your changes quickly, just hit @kbd{C-c C-q}
(@code{c-indent-defun}) to reindent the entire function.  The example
should now look like:

@example
@group
 1: int add( int val, int incr, int doit )
 2: @{
 3:   if( doit )
 4:   @{
 5:     return( val + incr );
 6:   @}
 7:   return( val );
 8: @}
@end group
@end example

Notice how just changing the open brace offset on line 4 is all we
needed to do.  Since the other affected lines are indented relative to
line 4, they are automatically indented the way you'd expect.  For more
complicated examples, this may not always work.  The general approach to
take is to always start adjusting offsets for lines higher up in the
file, then reindent and see if any following lines need further
adjustments.

@deffn Command c-set-offset symbol offset
@findex set-offset (c-)
@kindex C-c C-o
This is the command bound to @kbd{C-c C-o}.  It provides a convenient
way to set offsets on @code{c-offsets-alist} both interactively (see
the example above) and from your mode hook.

It takes two arguments when used programmatically: @var{symbol} is the
syntactic element symbol to change and @var{offset} is the new offset
for that syntactic element.
@end deffn


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Permanent Customization, Hooks, Interactive Customization, Customizing Indentation
@comment node-name, next, previous, up
@section Permanent Customization
@cindex customization, permanent
@cindex permanent customization
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

To make your changes permanent, you need to add some lisp code to your
@file{.emacs} file.  @ccmode{} supports many different ways to be
configured, from the straightforward way by setting variables globally
in @file{.emacs} or in the Customization interface, to the complex and
precisely controlled way by using styles and hook functions.

The simplest way of customizing @ccmode{} permanently is to set the
variables in your @file{.emacs} with @code{setq} and similar commands.
So to make a permanent setting of @code{substatement-open} to 0, add
this to the @file{.emacs} file:

@example
@group
(setq c-offsets-alist
      '((substatement-open . 0)))
@end group
@end example

When @ccmode{} initializes a buffer, it will fill out
@code{c-offsets-alist} with the remaining syntactic symbols according to
the style system.

You can also use the more user friendly Customization interface, but
this manual does not cover how that works.

Variables set like this at the top level in @file{.emacs} take effect in
all @ccmode{} buffers, regardless of language.  The indentation style
related variables, e.g. @code{c-offsets-alist}, that you don't set this
way get their value from the style system (@pxref{Styles}), and they
therefore depend on the setting of @code{c-default-style}.  Note that if
you use Customize, this means that the greyed-out default values
presented there might not be the ones you actually get, since the actual
values depend on the style, which may very well be different for
different languages.

If you want to make more advanced configurations, e.g. language-specific
customization, setting global variables isn't enough.  For that you can
use the language hooks, see @ref{Hooks}, and/or the style system, see
@ref{Styles}.

@defopt c-style-variables-are-local-p
@vindex style-variables-are-local-p (c-)
By default, all style variables are buffer local, so that different
buffers can have different style settings.  If you only use one style
in all the files you edit you might want to share them between buffers
so that a change take effect in all buffers.  That's done by setting
this variable to @code{nil}.  The value takes effect when @ccmode{} is
activated in a buffer for the first time in the Emacs session, so you
typically set it in your @file{.emacs} file and then restart Emacs.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Hooks, Styles, Permanent Customization, Customizing Indentation
@comment node-name, next, previous, up
@section Hooks
@cindex mode hooks
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} provides several hooks that you can use to customize the mode
according to your coding style.  Each language mode has its own hook,
adhering to standard Emacs major mode conventions.  There is also one
general hook and one package initialization hook:

@defvar c-initialization-hook
@vindex initialization-hook (c-)
Hook run only once per Emacs session, when @ccmode{} is initialized.
@end defvar

@defvar c-mode-common-hook
@vindex mode-common-hook (c-)
Common hook across all languages.  It's run immediately before the
language specific hook.
@end defvar

@defvar c-mode-hook
@defvarx c++-mode-hook
@defvarx objc-mode-hook
@defvarx java-mode-hook
@defvarx idl-mode-hook
@defvarx pike-mode-hook
@defvarx awk-mode-hook
The language specific mode hooks.  The appropriate one is run as the
last thing when you enter that language mode.
@end defvar

Note that all the language-specific mode setup that CC Mode does is done
prior to both @code{c-mode-common-hook} and the language specific hook.
That includes installing the indentation style, which can be mode
specific (and also is by default for Java mode).  Thus, any style
settings done in @code{c-mode-common-hook} will override whatever
language-specific style is chosen by @code{c-default-style}.

Here's a simplified example of what you can add to your @file{.emacs}
file to do things whenever any @ccmode{} language is edited.  See the
Emacs manuals for more information on customizing Emacs via hooks.
@xref{Sample .emacs File}, for a more complete sample @file{.emacs}
file.

@example
(defun my-c-mode-common-hook ()
  ;; my customizations for all of c-mode and related modes
  (no-case-fold-search)
  )
(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
@end example


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Styles, Advanced Customizations, Hooks, Customizing Indentation
@comment node-name, next, previous, up
@section Styles
@cindex styles
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Most people only need to edit code formatted in just a few well-defined
and consistent styles.  For example, their organization might impose a
``blessed'' style that all its programmers must conform to.  Similarly,
people who work on GNU software will have to use the GNU coding style.
Some shops are more lenient, allowing a variety of coding styles, and as
programmers come and go, there could be a number of styles in use.  For
this reason, @ccmode{} makes it convenient for you to set up logical
groupings of customizations called @dfn{styles}, associate a single name
for any particular style, and pretty easily start editing new or
existing code using these styles.

@cindex style variables
The variables that the style system affect are called @dfn{style
variables}.  They are handled specially in several ways:

@itemize @bullet
@item
Style variables are by default buffer local variables.  However, they
can instead be made global by setting
@code{c-style-variables-are-local-p} to @code{nil} before @ccmode{} is
initialized.

@item
@vindex c-old-style-variable-behavior
@vindex old-style-variable-behavior (c-)
The default value of any style variable (with two exceptions --- see
below) is the special symbol @code{set-from-style}.  Variables that are
still set to that symbol when a @ccmode{} buffer is initialized will be
set according to the current style, otherwise they will keep their
current value@footnote{This is a big change from versions of @ccmode{}
earlier than 5.26, where such settings would get overridden by the style
system unless special precautions were taken.  That was changed since it
was counterintuitive and confusing, especially to novice users.  If your
configuration depends on the old overriding behavior, you can set the
variable @code{c-old-style-variable-behavior} to non-@code{nil}.}.

Note that when we talk about the ``default value'' for a style variable,
we don't mean the @code{set-from-style} symbol that all style variables
are set to initially, but instead the value it will get at mode
initialization when neither a style nor a global setting has set its
value.

The style variable @code{c-offsets-alist} is handled a little
differently from the other style variables.  It's an association list,
and is thus by default set to the empty list, @code{nil}.  When the
style system is initialized, any syntactic symbols already on it are
kept --- only the missing ones are filled in from the chosen style.

The style variable @code{c-special-indent-hook} is also handled in a
special way.  Styles may only add more functions on this hook, so the
global settings on it are always preserved@footnote{This did not change
in version 5.26.}.

@item
The global settings of style variables get captured in the special
@code{user} style, which is used as the base for all the other styles.
@xref{Built-in Styles}, for details.
@end itemize

The style variables are:
@code{c-basic-offset},
@code{c-comment-only-line-offset},
@code{c-block-comment-prefix},
@code{c-comment-prefix-regexp},
@code{c-cleanup-list},
@code{c-hanging-braces-alist},
@code{c-hanging-colons-alist},
@code{c-hanging-semi&comma-criteria},
@code{c-backslash-column},
@code{c-backslash-max-column},
@code{c-special-indent-hook},
@code{c-label-minimum-indentation}, and
@code{c-offsets-alist}.

@menu
* Built-in Styles::
* Choosing a Style::
* Adding Styles::
* File Styles::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Built-in Styles, Choosing a Style, , Styles
@comment node-name, next, previous, up
@subsection Built-in Styles
@cindex styles, built-in
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If you're lucky, one of @ccmode{}'s built-in styles might be just
what you're looking for.  These include:

@table @code
@item gnu
@cindex GNU style
Coding style blessed by the Free Software Foundation
for C code in GNU programs.

@item k&r
@cindex K&R style
The classic Kernighan and Ritchie style for C code.

@item bsd
@cindex BSD style
Also known as ``Allman style'' after Eric Allman.

@item whitesmith
@cindex Whitesmith style
Popularized by the examples that came with Whitesmiths C, an early
commercial C compiler.

@item stroustrup
@cindex Stroustrup style
The classic Stroustrup style for C++ code.

@item ellemtel
@cindex Ellemtel style
Popular C++ coding standards as defined by ``Programming in C++, Rules
and Recommendations,'' Erik Nyquist and Mats Henricson,
Ellemtel@footnote{This document is available at
@uref{http://www.doc.ic.ac.uk/lab/cplus/c++.rules/} among other
places.}.

@item linux
@cindex Linux style
C coding standard for Linux (the kernel).

@item python
@cindex Python style
C coding standard for Python extension modules@footnote{Python is a
high level scripting language with a C/C++ foreign function interface.
For more information, see @uref{http://www.python.org/}.}.

@item java
@cindex Java style
The style for editing Java code.  Note that the default
value for @code{c-default-style} installs this style when you enter
@code{java-mode}.

@item user
@cindex User style
This is a special style for several reasons.  First, the
@ccmode{} customizations you do by using either the Customization
interface, or by writing @code{setq}'s at the top level of your
@file{.emacs} file, will be captured in the @code{user} style.  Also,
all other styles implicitly inherit their settings from @code{user}
style.  This means that for any styles you add via @code{c-add-style}
(@pxref{Adding Styles}) you need only define the differences between
your new style and @code{user} style.
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Choosing a Style, Adding Styles, Built-in Styles, Styles
@comment node-name, next, previous, up
@subsection Choosing a Style
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Use @kbd{C-c .} to choose a style interactively:

@deffn Command c-set-style style-name
@findex set-style (c-)
@kindex C-c .
Switch to the specified style in the current buffer.  Use
interactively like this:

@example
@kbd{C-c . @var{style-name} RET}
@end example

Note that all style names are case insensitive, even the ones you
define.

Setting a style in this way does @emph{not} automatically reindent your
file.  For commands that you can use to view the effect of your changes,
see @ref{Commands}.
@end deffn

The default style in all newly created buffers is @code{gnu}, except
in Java mode where it's @code{java}.  Although the @code{user} style
is not the default style, any style variable settings you do with the
Customization interface or on the top level in your @file{.emacs} file
will by default override the style system, so you don't need to set
@code{c-default-style} to @code{user} to see the effect of such
settings.

@defopt c-default-style
@vindex default-style (c-)
This variable specifies which style to install by default in new
buffers.  It takes either a style name string, or an association list
of major mode symbols to style names:

@enumerate
@item
When @code{c-default-style} is a string, it must be an existing style
name.  This style is then used for all modes.

@item
When @code{c-default-style} is an association list, the mode language
is looked up to find a style name string.

@item
If @code{c-default-style} is an association list where the mode
language mode isn't found then the special symbol @samp{other} is
looked up.  If it's found then the associated style is used.

@item
If @samp{other} is not found then the @samp{gnu} style is used.

@item
In all cases, the style described in @code{c-default-style} is installed 
@emph{before} the language hooks are run, so you can always override
this setting by including an explicit call to @code{c-set-style} in your 
language mode hook, or in @code{c-mode-common-hook}.
@end enumerate
@end defopt

@defvar c-indentation-style
@vindex indentation-style (c-)
This variable always contains the buffer's current style name, as a
string.
@end defvar


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Adding Styles, File Styles, Choosing a Style, Styles
@comment node-name, next, previous, up
@subsection Adding Styles
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If none of the built-in styles is appropriate, you'll probably want to
add a new @dfn{style definition}.  Styles are kept in the
@code{c-style-alist} variable, but you should never modify this
variable directly.  Instead, @ccmode{} provides the function
@code{c-add-style} that you can use to easily add new styles or change
existing styles:

@defun c-add-style stylename description &optional set-p
@findex add-style (c-)
Add or update a style.  If @var{stylename} is not already in
@code{c-style-alist} then a new style according to @var{description}
is added, otherwise the existing style is changed.  If the optional
@var{set-p} is non-@code{nil} then the new style is applied to the
current buffer as well.

@comment TBD: The next paragraph is bogus.  I really need to better
@comment document adding styles, including setting up inherited styles.

The sample @file{.emacs} file provides a concrete example of how a new
style can be added and automatically set.  @xref{Sample .emacs File}.
@end defun

@defvar c-style-alist
@vindex style-alist (c-)
This is the variable that holds the definitions for the styles.  It
should not be changed directly; use @code{c-add-style} instead.
@end defvar


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    File Styles, , Adding Styles, Styles
@comment node-name, next, previous, up
@subsection File Styles
@cindex styles, file local
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex file local variables

The Emacs manual describes how you can customize certain variables on
a per-file basis by including a @dfn{file local variable} block at the
end of the file.  So far, you've only seen a functional interface to
@ccmode{} customization, which can't be used there.  @ccmode{}
provides two variables allow customization of the indentation style on
a per-file basis:

@defvar c-file-style
@vindex file-style (c-)
This variable can be set to a style name string.  When the file is
visited, @ccmode{} will automatically set the file's style to this
one using @code{c-set-style}.
@end defvar

@defvar c-file-offsets
@vindex file-offsets (c-)
This variable takes an association list similar to what is allowed in
@code{c-offsets-alist}.  When the file is visited, @ccmode{} will
automatically institute these offsets using @code{c-set-offset}.
@end defvar

Note that file style settings (i.e. @code{c-file-style}) are applied
before file offset settings (i.e. @code{c-file-offsets}).  Also, if
either of these are set in a file's local variable section, all the
style variable values are made local to that buffer.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Advanced Customizations, , Styles, Customizing Indentation
@comment node-name, next, previous, up
@section Advanced Customizations
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

For most users, @ccmode{} will support their coding styles with very
little need for more advanced customizations.  Usually, one of the
standard styles (@pxref{Built-in Styles}) will do the trick.  At most,
perhaps one of the syntactic symbol offsets will need to be tweaked
slightly, or maybe @code{c-basic-offset} will need to be changed.
However, some styles require a more flexible framework for
customization, and one of the real strengths of @ccmode{} is that the
syntactic analysis model provides just such a framework. This allows
you to implement custom indentation calculations for situations not
handled by the mode directly.

@menu
* Custom Indentation Functions::
* Custom Brace and Colon Hanging::
* Customizing Semicolons and Commas::
* Other Special Indentations::
@end menu

@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Custom Indentation Functions, Custom Brace and Colon Hanging, , Advanced Customizations
@comment node-name, next, previous, up
@subsection Custom Indentation Functions
@cindex customization, indentation functions
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The most flexible way to customize @ccmode{} is by writing custom
indentation functions, and associating them with specific syntactic
symbols (@pxref{Syntactic Symbols}).  @ccmode{} itself uses indentation
functions to provide more sophisticated indentation, for example when
lining up C++ stream operator blocks:

@example
@group
 1: void main(int argc, char**)
 2: @{
 3:   cout << "There were "
 4:     << argc
 5:     << "arguments passed to the program"
 6:     << endl;
 7: @}
@end group
@end example

In this example, lines 4 through 6 are assigned the @code{stream-op}
syntactic symbol.  Here, @code{stream-op} has an offset of @code{+}, and
with a @code{c-basic-offset} of 2, you can see that lines 4 through 6
are simply indented two spaces to the right of line 3.  But perhaps we'd
like @ccmode{} to be a little more intelligent so that it aligns
all the @samp{<<} symbols in lines 3 through 6.  To do this, we have
to write a custom indentation function which finds the column of the first
stream operator on the first line of the statement.  Here is sample 
lisp code implementing this:

@example
(defun c-lineup-streamop (langelem)
  (save-excursion
    (goto-char (cdr langelem))
    (re-search-forward "<<\\|>>" (c-point 'eol) 'move)
    (goto-char (match-beginning 0))
    (vector (current-column))))
@end example

Indentation functions take a single argument, which is a syntactic
component cons cell (@pxref{Syntactic Analysis}).  The function can
return an integer which is added to the running total indentation for
the line, or a vector containing an integer which is an absolute
column to align to.  Usually an absolute column is wanted when
aligning to existing text, as in this example.

The function should return @code{nil} if it's used in a situation where
it doesn't want to make any decision.  If the function is used in a list
expression (@pxref{Customizing Indentation}), that will cause @ccmode{}
to go on and check the next entry in the list.

Now, to associate the function @code{c-lineup-streamop} with the
@code{stream-op} syntactic symbol, we can add something like the
following to our @code{c++-mode-hook}@footnote{It probably makes more
sense to add this to @code{c++-mode-hook} than @code{c-mode-common-hook}
since stream operators are only relevant for C++.}:

@example
(c-set-offset 'stream-op 'c-lineup-streamop)
@end example

Now the function looks like this after reindenting (using @kbd{C-c
C-q}):

@example
@group
 1: void main(int argc, char**)
 2: @{
 3:   cout << "There were "
 4:        << argc
 5:        << " arguments passed to the program"
 6:        << endl;
 7: @}
@end group
@end example

Custom indentation functions can be as simple or as complex as you like,
and any syntactic symbol that appears in @code{c-offsets-alist} can have
a custom indentation function associated with it.

@ccmode{} comes with an extensive set of predefined indentation
functions, not all of which are used by the default styles.  So there's
a good chance the function you want already exists.  @xref{Indentation
Functions}, for a list of them.  If you have written an indentation
function that you think is generally useful, you're very welcome to
contribute it; please contact @email{bug-cc-mode@@gnu.org}.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Custom Brace and Colon Hanging, Customizing Semicolons and Commas, Custom Indentation Functions, Advanced Customizations
@comment node-name, next, previous, up
@subsection Custom Brace and Colon Hanging
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@vindex c-hanging-braces-alist
@vindex hanging-braces-alist (c-)
Syntactic symbols aren't the only place where you can customize
@ccmode{} with the lisp equivalent of callback functions.  Brace
``hanginess'' can also be determined by custom functions associated with
syntactic symbols on the @code{c-hanging-braces-alist} style variable.
Remember that @var{action}'s are typically a list containing some
combination of the symbols @code{before} and @code{after}
(@pxref{Hanging Braces}).  However, an @var{action} can also be a
function which gets called when a brace matching that syntactic symbol
is entered.

@cindex customization, brace hanging
These @var{action} functions are called with two arguments: the
syntactic symbol for the brace, and the buffer position at which the
brace was inserted.  The @var{action} function is expected to return a
list containing some combination of @code{before} and @code{after},
including neither of them (i.e. @code{nil}).  This return value has the
normal brace hanging semantics.

As an example, @ccmode{} itself uses this feature to dynamically
determine the hanginess of braces which close ``do-while''
constructs:

@example
void do_list( int count, char** atleast_one_string )
@{
    int i=0;
    do @{
        handle_string( atleast_one_string[i] );
        i++;
    @} while( i < count );
@}
@end example

@ccmode{} assigns the @code{block-close} syntactic symbol to the
brace that closes the @code{do} construct, and normally we'd like the
line that follows a @code{block-close} brace to begin on a separate
line.  However, with ``do-while'' constructs, we want the
@code{while} clause to follow the closing brace.  To do this, we
associate the @code{block-close} symbol with the @var{action} function
@code{c-snug-do-while}:

@example
(defun c-snug-do-while (syntax pos)
  "Dynamically calculate brace hanginess for do-while statements."
  (save-excursion
    (let (langelem)
      (if (and (eq syntax 'block-close)
               (setq langelem (assq 'block-close c-syntactic-context))
               (progn (goto-char (cdr langelem))
                      (if (= (following-char) ?@{)
                          (forward-sexp -1))
                      (looking-at "\\<do\\>[^_]")))
          '(before)
        '(before after)))))
@end example

@findex c-snug-do-while
@findex snug-do-while (c-)
This function simply looks to see if the brace closes a ``do-while''
clause and if so, returns the list @samp{(before)} indicating
that a newline should be inserted before the brace, but not after it.
In all other cases, it returns the list @samp{(before after)} so
that the brace appears on a line by itself.

@defvar c-syntactic-context
@vindex syntactic-context (c-)
During the call to the indentation or brace hanging @var{action}
function, this variable is bound to the full syntactic analysis list.
@end defvar

@cindex customization, colon hanging
@vindex c-hanging-colons-alist
@vindex hanging-colons-alist (c-)
Note that for symmetry, colon hanginess should be customizable by
allowing function symbols as @var{action}s on the
@code{c-hanging-colons-alist} style variable.  Since no use has actually
been found for this feature, it isn't currently implemented!


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Customizing Semicolons and Commas, Other Special Indentations, Custom Brace and Colon Hanging, Advanced Customizations
@comment node-name, next, previous, up
@subsection Customizing Semicolons and Commas
@cindex customization, semicolon newlines
@cindex customization, comma newlines
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You can also customize the insertion of newlines after semicolons and
commas when the auto-newline minor mode is enabled (@pxref{Minor
Modes}).

@defopt c-hanging-semi&comma-criteria
@vindex hanging-semi&comma-criteria (c-)
This style variable takes a list of hooks that get called when a
semicolon or comma is inserted.  The hooks are called in order without
arguments, and are expected to return one of the following values:

@table @code
@item t
A newline is inserted, and no more functions from the list are called.
@item stop
No more functions from the list are called, but no newline is
inserted.
@item nil
No determination is made, and the next function in the list is called.
@end table

If every function in the list is called without a determination being
made, then no newline is added. The default value for this variable is a
list containing a single function which inserts newlines only after
semicolons which do not appear inside parenthesis lists (i.e. those
that separate @code{for}-clause statements).
@end defopt

@defun c-semi&comma-no-newlines-before-nonblanks
@findex semi&comma-no-newlines-before-nonblanks (c-)
This is an example of a criteria function, provided by @ccmode{}.  It
prevents newlines from being inserted after semicolons when there is a
non-blank following line.  Otherwise, it makes no determination.  To
use, add this function to the front of the
@code{c-hanging-semi&comma-criteria} list.

@example
(defun c-semi&comma-no-newlines-before-nonblanks ()
  (save-excursion
    (if (and (eq last-command-char ?\;)
             (zerop (forward-line 1))
             (not (looking-at "^[ \t]*$")))
        'stop
      nil)))
@end example
@end defun

@defun c-semi&comma-inside-parenlist
@findex semi&comma-inside-parenlist (c-)
@defunx c-semi&comma-no-newlines-for-oneline-inliners
@findex semi&comma-no-newlines-for-oneline-inliners (c-)
The function @code{c-semi&comma-inside-parenlist} is what prevents
newlines from being inserted inside the parenthesis list of @code{for}
statements.  In addition to
@code{c-semi&comma-no-newlines-before-nonblanks} described above,
@ccmode{} also comes with the criteria function
@code{c-semi&comma-no-newlines-for-oneline-inliners}, which suppresses
newlines after semicolons inside one-line inline method definitions
(e.g. in C++ or Java).
@end defun


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Other Special Indentations, , Customizing Semicolons and Commas, Advanced Customizations
@comment node-name, next, previous, up
@subsection Other Special Indentations
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Here are the remaining odds and ends regarding indentation:

@defopt c-label-minimum-indentation
@vindex label-minimum-indentation (c-)
In @samp{gnu} style (@pxref{Built-in Styles}), a minimum indentation
is imposed on lines inside top-level constructs.  This minimum
indentation is controlled by this style variable.  The default value
is 1.
@end defopt

@defopt c-special-indent-hook
@vindex special-indent-hook (c-)
This style variable is a standard hook variable that is called after
every line is indented by @ccmode{}.  You can use it to do any special
indentation or line adjustments your style dictates, such as adding
extra indentation to constructors or destructor declarations in a
class definition, etc.  Note that you should not change point or mark
inside your @code{c-special-indent-hook} functions, i.e. you'll
probably want to wrap your function in a @code{save-excursion}.

Setting @code{c-special-indent-hook} in your style definition is
handled slightly differently than other variables.  In your style
definition, you should set the value for @code{c-special-indent-hook}
to a function or list of functions, which will be appended to
@code{c-special-indent-hook} using @code{add-hook}.  That way, the
current setting for the buffer local value of
@code{c-special-indent-hook} won't be overridden.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Syntactic Symbols, Indentation Functions, Customizing Indentation, Top
@comment node-name, next, previous, up
@chapter Syntactic Symbols
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex syntactic symbols, brief list
@vindex c-offsets-alist
@vindex offsets-alist (c-)
Here is a complete list of the recognized syntactic symbols as described
in the @code{c-offsets-alist} style variable, along with a brief
description.  More detailed descriptions follow.

@table @code
@item string
Inside a multiline string.
@item c
Inside a multiline C style block comment.
@item defun-open
Brace that opens a top-level function definition.
@item defun-close
Brace that closes a top-level function definition.
@item defun-block-intro
The first line in a top-level defun.
@item class-open
Brace that opens a class definition.
@item class-close
Brace that closes a class definition.
@item inline-open
Brace that opens an in-class inline method.
@item inline-close
Brace that closes an in-class inline method.
@item func-decl-cont
The region between a function definition's argument list and the
function opening brace (excluding K&R argument declarations).  In C, you
cannot put anything but whitespace and comments in this region, however
in C++ and Java, @code{throws} declarations and other things can appear
here.
@item knr-argdecl-intro
First line of a K&R C argument declaration.
@item knr-argdecl
Subsequent lines in a K&R C argument declaration.
@item topmost-intro
The first line in a ``topmost'' definition.
@item topmost-intro-cont
Topmost definition continuation lines.  This is only used in the parts
that aren't covered by other symbols such as @code{func-decl-cont} and
@code{knr-argdecl}.
@item member-init-intro
First line in a member initialization list.
@item member-init-cont
Subsequent member initialization list lines.
@item inher-intro
First line of a multiple inheritance list.
@item inher-cont
Subsequent multiple inheritance lines.
@item block-open
Statement block open brace.
@item block-close
Statement block close brace.
@item brace-list-open
Open brace of an enum or static array list.
@item brace-list-close
Close brace of an enum or static array list.
@item brace-list-intro
First line in an enum or static array list.
@item brace-list-entry
Subsequent lines in an enum or static array list.
@item brace-entry-open
Subsequent lines in an enum or static array list where the line begins
with an open brace.
@item statement
A statement.
@item statement-cont
A continuation of a statement.
@item statement-block-intro
The first line in a new statement block.
@item statement-case-intro
The first line in a case block.
@item statement-case-open
The first line in a case block that starts with a brace.
@item substatement
The first line after a conditional or loop construct.
@item substatement-open
The brace that opens a substatement block.
@item substatement-label
The first line after a conditional or loop construct if it's a label.
@item case-label
A label in a @code{switch} block.
@item access-label
C++ access control label.
@item label
Any other label.
@item do-while-closure
The @code{while} line that ends a @code{do}-@code{while} construct.
@item else-clause
The @code{else} line of an @code{if}-@code{else} construct.
@item catch-clause
The @code{catch} or @code{finally} (in Java) line of a
@code{try}-@code{catch} construct.
@item comment-intro
A line containing only a comment introduction.
@item arglist-intro
The first line in an argument list.
@item arglist-cont
Subsequent argument list lines when no arguments follow on the same line
as the arglist opening paren.
@item arglist-cont-nonempty
Subsequent argument list lines when at least one argument follows on the
same line as the arglist opening paren.
@item arglist-close
The solo close paren of an argument list.
@item stream-op
Lines continuing a stream operator (C++ only).
@item inclass
The line is nested inside a class definition.
@item cpp-macro
The start of a preprocessor macro definition.
@item cpp-define-intro
The first line inside a multiline preproprocessor macro if
@code{c-syntactic-indentation-in-macros} is set.
@item cpp-macro-cont
All lines inside multiline preprocessor macros if
@code{c-syntactic-indentation-in-macros} is @code{nil}.
@item friend
A C++ friend declaration.
@item objc-method-intro
The first line of an Objective-C method definition.
@item objc-method-args-cont
Lines continuing an Objective-C method definition.
@item objc-method-call-cont
Lines continuing an Objective-C method call.
@item extern-lang-open
Brace that opens an @code{extern} block (e.g. @code{extern "C" @{...@}}).
@item extern-lang-close
Brace that closes an @code{extern} block.
@item inextern-lang
Analogous to @code{inclass} syntactic symbol, but used inside
@code{extern} blocks.
@item namespace-open
@itemx namespace-close
@itemx innamespace
These are analogous to the three @code{extern-lang} symbols above, but
are returned for C++ namespace blocks.
@item module-open
@itemx module-close
@itemx inmodule
Analogous to the above, but for CORBA IDL @code{module} blocks.
@item composition-open
@itemx composition-close
@itemx incomposition
Analogous to the above, but for CORBA CIDL @code{composition} blocks.
@item template-args-cont
C++ template argument list continuations.
@item inlambda
Analogous to @code{inclass} syntactic symbol, but used inside lambda
(i.e. anonymous) functions.  Only used in Pike mode.
@item lambda-intro-cont
Lines continuing the header of a lambda function, i.e. between the
@code{lambda} keyword and the function body.  Only used in Pike mode.
@item inexpr-statement
A statement block inside an expression.  The gcc C extension of this is
recognized.  It's also used for the special functions that takes a
statement block as an argument in Pike.
@item inexpr-class
A class definition inside an expression.  This is used for anonymous
classes in Java.  It's also used for anonymous array initializers in
Java.
@end table

@ssindex -open symbols
@ssindex -close symbols
Most syntactic symbol names follow a general naming convention.  When a
line begins with an open or close brace, the syntactic symbol will
contain the suffix @code{-open} or @code{-close} respectively.

@ssindex -intro symbols
@ssindex -cont symbols
@ssindex -block-intro symbols
Usually, a distinction is made between the first line that introduces a
construct and lines that continue a construct, and the syntactic symbols
that represent these lines will contain the suffix @code{-intro} or
@code{-cont} respectively.  As a sub-classification of this scheme, a
line which is the first of a particular brace block construct will
contain the suffix @code{-block-intro}.

Let's look at some examples to understand how this works.  Remember that
you can check the syntax of any line by using @kbd{C-c C-s}.

@example
 1: void
 2: swap( int& a, int& b )
 3: @{
 4:     int tmp = a;
 5:     a = b;
 6:     b = tmp;
 7:     int ignored =
 8:         a + b;
 9: @}
@end example

@ssindex topmost-intro
@ssindex topmost-intro-cont
@ssindex defun-open
@ssindex defun-close
@ssindex defun-block-intro
Line 1 shows a @code{topmost-intro} since it is the first line that
introduces a top-level construct.  Line 2 is a continuation of the
top-level construct introduction so it has the syntax
@code{topmost-intro-cont}.  Line 3 shows a @code{defun-open} since it is
the brace that opens a top-level function definition.  Line 9 is the
corresponding
@code{defun-close} since it contains the brace that closes the top-level
function definition.  Line 4 is a @code{defun-block-intro}, i.e. it is
the first line of a brace-block, enclosed in a
top-level function definition.

@ssindex statement
@ssindex statement-cont
Lines 5, 6, and 7 are all given @code{statement} syntax since there
isn't much special about them.  Note however that line 8 is given
@code{statement-cont} syntax since it continues the statement begun
on the previous line.

Here's another example, which illustrates some C++ class syntactic
symbols:

@example
 1: class Bass
 2:     : public Guitar,
 3:       public Amplifiable
 4: @{
 5: public:
 6:     Bass()
 7:         : eString( new BassString( 0.105 )),
 8:           aString( new BassString( 0.085 )),
 9:           dString( new BassString( 0.065 )),
10:           gString( new BassString( 0.045 ))
11:     @{
12:         eString.tune( 'E' );
13:         aString.tune( 'A' );
14:         dString.tune( 'D' );
15:         gString.tune( 'G' );
16:     @}
17:     friend class Luthier;
18: @};
@end example

@ssindex class-open
@ssindex class-close
As in the previous example, line 1 has the @code{topmost-intro} syntax.
Here however, the brace that opens a C++ class definition on line 4 is
assigned the @code{class-open} syntax.  Note that in C++, classes,
structs, and unions are essentially equivalent syntactically (and are
very similar semantically), so replacing the @code{class} keyword in the
example above with @code{struct} or @code{union} would still result in a
syntax of @code{class-open} for line 4 @footnote{This is the case even
for C and Objective-C.  For consistency, structs in all supported
languages are syntactically equivalent to classes.  Note however that
the keyword @code{class} is meaningless in C and Objective-C.}.
Similarly, line 18 is assigned @code{class-close} syntax.

@ssindex inher-intro
@ssindex inher-cont
Line 2 introduces the inheritance list for the class so it is assigned
the @code{inher-intro} syntax, and line 3, which continues the
inheritance list is given @code{inher-cont} syntax.

@ssindex access-label
@ssindex inclass
Hitting @kbd{C-c C-s} on line 5 shows the following analysis:

@example
((inclass 58) (access-label 58))
@end example

@noindent
The primary syntactic symbol for this line is @code{access-label} as
this a label keyword that specifies access protection in C++.  However,
because this line is also a top-level construct inside a class
definition, the analysis actually shows two syntactic symbols.  The
other syntactic symbol assigned to this line is @code{inclass}.
Similarly, line 6 is given both @code{inclass} and @code{topmost-intro}
syntax:

@example
((inclass 58) (topmost-intro 60))
@end example

@ssindex member-init-intro
@ssindex member-init-cont
Line 7 introduces a C++ member initialization list and as such is given
@code{member-init-intro} syntax.  Note that in this case it is
@emph{not} assigned @code{inclass} since this is not considered a
top-level construct.  Lines 8 through 10 are all assigned
@code{member-init-cont} since they continue the member initialization
list started on line 7.

@cindex in-class inline methods
@ssindex inline-open
@ssindex inline-close
Line 11's analysis is a bit more complicated:

@example
((inclass 58) (inline-open))
@end example

This line is assigned a syntax of both @code{inline-open} and
@code{inclass} because it opens an @dfn{in-class} C++ inline method
definition.  This is distinct from, but related to, the C++ notion of an
inline function in that its definition occurs inside an enclosing class
definition, which in C++ implies that the function should be inlined.
However, if the definition of the @code{Bass} constructor appeared
outside the class definition, the construct would be given the
@code{defun-open} syntax, even if the keyword @code{inline} appeared
before the method name, as in:

@example
 1: class Bass
 2:     : public Guitar,
 3:       public Amplifiable
 4: @{
 5: public:
 6:     Bass();
 7: @};
 8:
 9: inline
10: Bass::Bass()
11:     : eString( new BassString( 0.105 )),
12:       aString( new BassString( 0.085 )),
13:       dString( new BassString( 0.065 )),
14:       gString( new BassString( 0.045 ))
15: @{
16:     eString.tune( 'E' );
17:     aString.tune( 'A' );
18:     dString.tune( 'D' );
19:     gString.tune( 'G' );
20: @}
@end example

@ssindex friend
Returning to the previous example, line 16 is given @code{inline-close}
syntax, while line 12 is given @code{defun-block-open} syntax, and lines
13 through 15 are all given @code{statement} syntax.  Line 17 is
interesting in that its syntactic analysis list contains three
elements:

@example
((inclass 58) (topmost-intro 380) (friend))
@end example

The @code{friend} syntactic symbol is a modifier that typically does not
have a relative buffer position.

Template definitions introduce yet another syntactic symbol:

@example
 1: ThingManager <int,
 2:    Framework::Callback *,
 3:    Mutex> framework_callbacks;
@end example

Here, line 1 is analyzed as a @code{topmost-intro}, but lines 2 and 3
are both analyzed as @code{template-args-cont} lines.

Here is another (totally contrived) example which illustrates how syntax
is assigned to various conditional constructs:

@example
 1: void spam( int index )
 2: @{
 3:     for( int i=0; i<index; i++ )
 4:     @{
 5:         if( i == 10 )
 6:             do_something_special();
 7:         else
 8:           silly_label:
 9:             do_something( i );
10:     @}
11:     do @{
12:         another_thing( i-- );
13:     @}
14:     while( i > 0 );
15: @}
@end example

Only the lines that illustrate new syntactic symbols will be discussed.

@ssindex substatement-open
@ssindex substatement-block-intro
@ssindex block-close
Line 4 has a brace which opens a conditional's substatement block.  It
is thus assigned @code{substatement-open} syntax, and since line 5 is
the first line in the substatement block, it is assigned
@code{substatement-block-intro} syntax.  Line 10 contains the brace that
closes the inner substatement block, and is therefore given the syntax
@code{block-close}.  Line 13 is treated the same way.

@ssindex substatement
Lines 6 and 9 are also substatements of conditionals, but since they
don't start blocks they are given @code{substatement} syntax
instead of @code{substatement-open}.

@ssindex substatement-label
Line 8 contains a label, which is normally given @code{label} syntax.
This one is however a bit special since it's between a conditional and
its substatement.  It's analyzed as @code{substatement-label} to let you
handle this rather odd case differently from normal labels.

@ssindex else-clause
@ssindex catch-clause
Line 7 start with an @code{else} that matches the @code{if} statement on
line 5.  It is therefore given the @code{else-clause} syntax and is
anchored on the matching @code{if}.  The @code{try}-@code{catch}
constructs in C++ and Java are treated this way too, except that
@code{catch} and (in Java) @code{finally}, are marked with
@code{catch-clause}.

@ssindex do-while-closure
The @code{while} construct on line 14 that closes a @code{do}
conditional is given the special syntax @code{do-while-closure} if it
appears on a line by itself.  Note that if the @code{while} appeared on
the same line as the preceding close brace, that line would still have
@code{block-close} syntax.

Switch statements have their own set of syntactic symbols.  Here's an
example:

@example
 1: void spam( enum Ingredient i )
 2: @{
 3:     switch( i ) @{
 4:     case Ham:
 5:         be_a_pig();
 6:         break;
 7:     case Salt:
 8:         drink_some_water();
 9:         break;
10:     default:
11:         @{
12:             what_is_it();
13:             break;
14:         @}
15:     @}
14: @}
@end example

@ssindex case-label
@ssindex statement-case-intro
@ssindex statement-case-open
Here, lines 4, 7, and 10 are all assigned @code{case-label} syntax,
while lines 5 and 8 are assigned @code{statement-case-intro}.  Line 11
is treated slightly differently since it contains a brace that opens a
block --- it is given @code{statement-case-open} syntax.

@cindex brace lists
There are a set of syntactic symbols that are used to recognize
constructs inside of brace lists.  A brace list is defined as an
@code{enum} or aggregate initializer list, such as might statically
initialize an array of structs.  The three special aggregate constructs
in Pike, @code{(@{ @})}, @code{([ ])} and @code{(< >)}, are treated as
brace lists too.  An example:

@example
 1: static char* ingredients[] =
 2: @{
 3:     "Ham",
 4:     "Salt",
 5:     NULL
 6: @};
@end example

@ssindex brace-list-open
@ssindex brace-list-intro
@ssindex brace-list-close
@ssindex brace-list-entry
Following convention, line 2 in this example is assigned
@code{brace-list-open} syntax, and line 3 is assigned
@code{brace-list-intro} syntax.  Likewise, line 6 is assigned
@code{brace-list-close} syntax.  Lines 4 and 5 however, are assigned
@code{brace-list-entry} syntax, as would all subsequent lines in this
initializer list.

@ssindex brace-entry-open
Your static initializer might be initializing nested structures, for
example:

@example
 1: struct intpairs[] =
 2: @{
 3:     @{ 1, 2 @},
 4:     @{
 5:         3,
 6:         4
 7:     @}
 8:     @{ 1,
 9:       2 @},
10:     @{ 3, 4 @}
11: @};
@end example

Here, you've already seen the analysis of lines 1, 2, 3, and 11.  On
line 4, things get interesting; this line is assigned
@code{brace-entry-open} syntactic symbol because it's a bracelist entry
line that starts with an open brace.  Lines 5 and 6 (and line 9) are
pretty standard, and line 7 is a @code{brace-list-close} as you'd
expect.  Once again, line 8 is assigned as @code{brace-entry-open} as is
line 10.

External language definition blocks also have their own syntactic
symbols.  In this example:

@example
 1: extern "C"
 2: @{
 3:     int thing_one( int );
 4:     int thing_two( double );
 5: @}
@end example

@ssindex extern-lang-open
@ssindex extern-lang-close
@ssindex inextern-lang
@ssindex inclass
@noindent
line 2 is given the @code{extern-lang-open} syntax, while line 5 is given
the @code{extern-lang-close} syntax.  The analysis for line 3 yields:

@example
((inextern-lang) (topmost-intro 14))
@end example

@noindent
where @code{inextern-lang} is a modifier similar in purpose to
@code{inclass}.

There are various other top level blocks like @code{extern}, and they
are all treated in the same way except that the symbols are named after
the keyword that introduces the block.  E.g. C++ namespace blocks get
the three symbols @code{namespace-open}, @code{namespace-close} and
@code{innamespace}.  The currently recognized top level blocks are:

@table @asis
@item @code{extern-lang-open}, @code{extern-lang-close}, @code{inextern-lang}
@code{extern} blocks in C and C++.@footnote{These should logically be
named @code{extern-open}, @code{extern-close} and @code{inextern}, but
that isn't the case for historical reasons.}

@item @code{namespace-open}, @code{namespace-close}, @code{innamespace}
@ssindex namespace-open
@ssindex namespace-close
@ssindex innamespace
@code{namespace} blocks in C++.

@item @code{module-open}, @code{module-close}, @code{inmodule}
@ssindex module-open
@ssindex module-close
@ssindex inmodule
@code{module} blocks in CORBA IDL.

@item @code{composition-open}, @code{composition-close}, @code{incomposition}
@ssindex composition-open
@ssindex composition-close
@ssindex incomposition
@code{composition} blocks in CORBA CIDL.
@end table

A number of syntactic symbols are associated with parenthesis lists,
a.k.a argument lists, as found in function declarations and function
calls.  This example illustrates these:

@example
 1: void a_function( int line1,
 2:                  int line2 );
 3: 
 4: void a_longer_function(
 5:     int line1,
 6:     int line2
 7:     );
 8: 
 9: void call_them( int line1, int line2 )
10: @{
11:     a_function(
12:         line1,
13:         line2
14:         );
15: 
16:     a_longer_function( line1,
17:                        line2 );
18: @}
@end example

@ssindex arglist-intro
@ssindex arglist-close
Lines 5 and 12 are assigned @code{arglist-intro} syntax since they are
the first line following the open parenthesis, and lines 7 and 14 are
assigned @code{arglist-close} syntax since they contain the parenthesis
that closes the argument list.

@ssindex arglist-cont-nonempty
@ssindex arglist-cont
Lines that continue argument lists can be assigned one of two syntactic
symbols.  For example, Lines 2 and 17
are assigned @code{arglist-cont-nonempty} syntax.  What this means
is that they continue an argument list, but that the line containing the
parenthesis that opens the list is @emph{not empty} following the open
parenthesis.  Contrast this against lines 6 and 13 which are assigned
@code{arglist-cont} syntax.  This is because the parenthesis that opens
their argument lists is the last character on that line.

Note that there is no @code{arglist-open} syntax.  This is because any
parenthesis that opens an argument list, appearing on a separate line,
is assigned the @code{statement-cont} syntax instead.

A few miscellaneous syntactic symbols that haven't been previously
covered are illustrated by this C++ example:

@example
 1: void Bass::play( int volume )
 2: const
 3: @{
 4:     /* this line starts a multiline
 5:      * comment.  This line should get `c' syntax */
 6: 
 7:     char* a_multiline_string = "This line starts a multiline \
 8: string.  This line should get `string' syntax.";
 9: 
10:   note:
11:     @{
12: #ifdef LOCK
13:         Lock acquire();
14: #endif // LOCK
15:         slap_pop();
16:         cout << "I played "
17:              << "a note\n";
18:     @}
19: @}
@end example

The lines to note in this example include:

@itemize @bullet
@item
@ssindex func-decl-cont
Line 2 is assigned the @code{func-decl-cont} syntax.

@item
@ssindex comment-intro
Line 4 is assigned both @code{defun-block-intro} @emph{and}
@code{comment-intro} syntax.

@item
@ssindex c
Line 5 is assigned @code{c} syntax.

@item
@cindex syntactic whitespace
Line 6 which, even though it contains nothing but whitespace, is
assigned @code{defun-block-intro}.  Note that the appearance of the
comment on lines 4 and 5 do not cause line 6 to be assigned
@code{statement} syntax because comments are considered to be
@dfn{syntactic whitespace}, which are ignored when analyzing
code.

@item
@ssindex string
Line 8 is assigned @code{string} syntax.

@item
@ssindex label
Line 10 is assigned @code{label} syntax.

@item
@ssindex block-open
Line 11 is assigned @code{block-open} syntax.

@item
@ssindex cpp-macro
Lines 12 and 14 are assigned @code{cpp-macro} syntax in addition to the
normal syntactic symbols (@code{statement-block-intro} and
@code{statement}, respectively).  Normally @code{cpp-macro} is
configured to cancel out the normal syntactic context to make all
preprocessor directives stick to the first column, but that's easily
changed if you want preprocessor directives to be indented like the rest
of the code.

@item
@ssindex stream-op
Line 17 is assigned @code{stream-op} syntax.
@end itemize

@cindex multiline macros
@cindex syntactic whitespace
@ssindex cpp-define-intro
Multiline preprocessor macro definitions are normally handled just like
other code, i.e. the lines inside them are indented according to the
syntactic analysis of the preceding lines inside the macro.  The first
line inside a macro definition (i.e. the line after the starting line of
the cpp directive itself) gets @code{cpp-define-intro}.  In this example:

@example
 1: #define LIST_LOOP(cons, listp)                         \
 2:   for (cons = listp; !NILP (cons); cons = XCDR (cons)) \
 3:     if (!CONSP (cons))                                 \
 4:       signal_error ("Invalid list format", listp);     \
 5:     else
@end example

@noindent
line 1 is given the syntactic symbol @code{cpp-macro}.  The first line
of a cpp directive is always given that symbol.  Line 2 is given
@code{cpp-define-intro}, so that you can give the macro body as a whole
some extra indentation.  Lines 3 through 5 are then analyzed as normal
code, i.e. @code{substatement} on lines 3 and 4, and @code{else-clause}
on line 5.

The syntactic analysis inside macros can be turned off with
@code{c-syntactic-indentation-in-macros}.  In that case, lines 2 through
5 would all be given @code{cpp-macro-cont} with a relative buffer
position pointing to the @code{#} which starts the cpp
directive@footnote{This is how @ccmode{} 5.28 and earlier analyzed
macros.}.

@xref{Macro Handling}, for more info about the treatment of macros.

In Objective-C buffers, there are three additional syntactic symbols
assigned to various message calling constructs.  Here's an example
illustrating these:

@example
 1: - (void)setDelegate:anObject
 2:           withStuff:stuff
 3: @{
 4:     [delegate masterWillRebind:self
 5:               toDelegate:anObject
 6:               withExtraStuff:stuff];
 7: @}
@end example

@ssindex objc-method-intro
@ssindex objc-method-args-cont
@ssindex objc-method-call-cont
Here, line 1 is assigned @code{objc-method-intro} syntax, and line 2 is
assigned @code{objc-method-args-cont} syntax.  Lines 5 and 6 are both
assigned @code{objc-method-call-cont} syntax.

Java has a concept of anonymous classes, which may look something like
this:

@example
 1: public void watch(Observable o) @{
 2:     o.addObserver(new Observer() @{
 3:             public void update(Observable o, Object arg) @{
 4:                 history.addElement(arg);
 5:             @}
 6:         @});
 7: @}
@end example

@ssindex inexpr-class
The brace following the @code{new} operator opens the anonymous class.
Lines 3 and 6 are assigned the @code{inexpr-class} syntax, besides the
@code{inclass} symbol used in normal classes.  Thus, the class will be
indented just like a normal class, with the added indentation given to
@code{inexpr-class}.

There are a few occasions where a statement block may be used inside an
expression.  One is in C code using the gcc extension for this, e.g:

@example
 1: int res = (@{
 2:         int y = foo (); int z;
 3:         if (y > 0) z = y; else z = - y;
 4:         z;
 5:     @});
@end example

@ssindex inexpr-statement
Lines 2 and 5 get the @code{inexpr-statement} syntax, besides the
symbols they'd get in a normal block.  Therefore, the indentation put on
@code{inexpr-statement} is added to the normal statement block
indentation.

In Pike code, there are a few other situations where blocks occur inside
statements, as illustrated here:

@example
 1: array itgob()
 2: @{
 3:     string s = map (backtrace()[-2][3..],
 4:                     lambda
 5:                         (mixed arg)
 6:                     @{
 7:                         return sprintf ("%t", arg);
 8:                     @}) * ", " + "\n";
 9:     return catch @{
10:             write (s + "\n");
11:         @};
12: @}
@end example

@ssindex inlambda
@ssindex lambda-intro-cont
Lines 4 through 8 contain a lambda function, which @ccmode{} recognizes
by the @code{lambda} keyword.  If the function argument list is put
on a line of its own, as in line 5, it gets the @code{lambda-intro-cont}
syntax.  The function body is handled as an inline method body, with the
addition of the @code{inlambda} syntactic symbol.  This means that line
6 gets @code{inlambda} and @code{inline-open}, and line 8 gets
@code{inline-close}@footnote{You might wonder why it doesn't get
@code{inlambda} too.  It's because the closing brace is relative to the
opening brace, which stands on its own line in this example.  If the
opening brace was hanging on the previous line, then the closing brace
would get the @code{inlambda} syntax too to be indented correctly.}.

@ssindex inexpr-statement
On line 9, @code{catch} is a special function taking a statement block
as its argument.  The block is handled as an in-expression statement
with the @code{inexpr-statement} syntax, just like the gcc extended C
example above.  The other similar special function, @code{gauge}, is
handled like this too.

@ssindex knr-argdecl-intro
@ssindex knr-argdecl
Two other syntactic symbols can appear in old style, non-prototyped C
code @footnote{a.k.a. K&R C, or Kernighan & Ritchie C}:

@example
 1: int add_three_integers(a, b, c)
 2:      int a;
 3:      int b;
 4:      int c;
 5: @{
 6:     return a + b + c;
 7: @}
@end example

Here, line 2 is the first line in an argument declaration list and so is
given the @code{knr-argdecl-intro} syntactic symbol.  Subsequent lines
(i.e. lines 3 and 4 in this example), are given @code{knr-argdecl}
syntax.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Indentation Functions, AWK Mode, Syntactic Symbols, Top
@comment node-name, next, previous, up
@chapter Indentation Functions
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@cindex indentation function
@cindex line-up function
Often there are cases when a simple offset setting on a syntactic
symbol isn't enough to get the desired indentation.  Therefore, it's
also possible to use an @dfn{indentation function} (a.k.a. @dfn{line-up
function}) for a syntactic symbol.

@ccmode{} comes with many predefined indentation functions for common
situations.  If none of these does what you want, you can write your
own, see @ref{Custom Indentation Functions}.  If you do, it's probably a
good idea to start working from one of these predefined functions, they
can be found in the file @file{cc-align.el}.

For every function below there is a ``works with'' list that indicates
which syntactic symbols the function is intended to be used with.

@macro workswith
@emph{Works with:@ }
@end macro
@ifinfo
@unmacro workswith
@macro workswith
Works with:
@end macro
@end ifinfo

@macro sssTBasicOffset
<--> @i{c-basic-offset}@c
@end macro

@macro sssTsssTBasicOffset
<--><--> @i{c-basic-offset}@c
@end macro

@macro hereFn{func}
<- @i{\func\}@c
@end macro

@c The TeX backend seems to insert extra spaces around the argument. :P
@iftex
@unmacro hereFn
@macro hereFn{func}
<-@i{\func\}@c
@end macro
@end iftex

@comment ------------------------------------------------------------

@defun c-indent-one-line-block
@findex indent-one-line-block (c-)
Indent a one line block @code{c-basic-offset} extra.  E.g:

@example
@group
if (n > 0)
    @{m+=n; n=0;@}      @hereFn{c-indent-one-line-block}
@sssTBasicOffset{}
@end group
@end example

@noindent
and

@example
@group
if (n > 0)
@{                     @hereFn{c-indent-one-line-block}
    m+=n; n=0;
@}
@end group
@end example

The block may be surrounded by any kind of parenthesis characters.
@code{nil} is returned if the line doesn't start with a one line block,
which makes the function usable in list expressions.

@workswith Almost all syntactic symbols, but most useful on the
@code{-open} symbols.
@end defun

@comment ------------------------------------------------------------

@defun c-indent-multi-line-block
@findex indent-multi-line-block (c-)
Indent a multiline block @code{c-basic-offset} extra.  E.g:

@example
@group
int *foo[] = @{
    NULL,                 
    @{17@},             @hereFn{c-indent-multi-line-block}
@end group
@end example

@noindent
and

@example
@group
int *foo[] = @{
    NULL,
        @{             @hereFn{c-indent-multi-line-block}
        17
        @},
    @sssTBasicOffset{}
@end group
@end example

The block may be surrounded by any kind of parenthesis characters.
@code{nil} is returned if the line doesn't start with a multiline
block, which makes the function usable in list expressions.

@workswith Almost all syntactic symbols, but most useful on the
@code{-open} symbols.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-argcont
@findex lineup-argcont (c-)
Line up a continued argument.  E.g:

@example
@group
foo (xyz, aaa + bbb + ccc
          + ddd + eee + fff);  @hereFn{c-lineup-argcont}
@end group
@end example

Only continuation lines like this are touched, @code{nil} is returned on
lines which are the start of an argument.

Within a gcc @code{asm} block, @code{:} is recognised as an argument
separator, but of course only between operand specifications, not in the
expressions for the operands.

@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-arglist
@findex lineup-arglist (c-)
Line up the current argument line under the first argument.

As a special case, if an argument on the same line as the open
parenthesis starts with a brace block opener, the indentation is
@code{c-basic-offset} only.  This is intended as a ``DWIM'' measure in
cases like macros that contains statement blocks, e.g:

@example
@group
A_VERY_LONG_MACRO_NAME (@{
        some (code, with + long, lines * in[it]);
    @});
@sssTBasicOffset{}
@end group
@end example

This is motivated partly because it's more in line with how code
blocks are handled, and partly since it approximates the behavior of
earlier CC Mode versions, which due to inaccurate analysis tended to
indent such cases this way.

@workswith @code{arglist-cont-nonempty}, @code{arglist-close}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-arglist-intro-after-paren
@findex lineup-arglist-intro-after-paren (c-)
Line up a line to just after the open paren of the surrounding paren or
brace block.

@workswith @code{defun-block-intro}, @code{brace-list-intro},
@code{statement-block-intro}, @code{statement-case-intro},
@code{arglist-intro}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-arglist-close-under-paren
@findex lineup-arglist-close-under-paren (c-)
Set your @code{arglist-close} syntactic symbol to this line-up function
so that parentheses that close argument lists will line up under the
parenthesis that opened the argument list.  It can also be used with
@code{arglist-cont} and @code{arglist-cont-nonempty} to line up all
lines inside a parenthesis under the open paren.

As a special case, if a brace block is opened at the same line as the
open parenthesis of the argument list, the indentation is
@code{c-basic-offset} only.  See @code{c-lineup-arglist} for further
discussion of this ``DWIM'' measure.

@workswith Almost all symbols, but are typically most useful on
@code{arglist-close}, @code{brace-list-close}, @code{arglist-cont} and
@code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-arglist-operators
@findex lineup-arglist-operators (c-)
Line up lines starting with an infix operator under the open paren.
Return @code{nil} on lines that don't start with an operator, to leave
those cases to other lineup functions.  Example:

@example
@group
if (  x < 10
   || at_limit (x,     @hereFn{c-lineup-arglist-operators}
                list)  @hereFn{c-lineup-arglist-operators@r{ returns nil}}
   )
@end group
@end example

Since this function doesn't do anything for lines without an infix
operator you typically want to use it together with some other lineup
settings, e.g. as follows (the @code{arglist-close} setting is just a
suggestion to get a consistent style):

@example
(c-set-offset 'arglist-cont
              '(c-lineup-arglist-operators 0))
(c-set-offset 'arglist-cont-nonempty
              '(c-lineup-arglist-operators c-lineup-arglist))
(c-set-offset 'arglist-close
              '(c-lineup-arglist-close-under-paren))
@end example

@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-C-comments
@findex lineup-C-comments (c-)
Line up C block comment continuation lines.  Various heuristics are used
to handle most of the common comment styles.  Some examples:

@example
@group
/*                 /**               /*
 * text             * text             text
 */                 */               */
@end group
@end example

@example
@group
/* text            /*                /**
   text            ** text            ** text
*/                 */                 */
@end group
@end example

@example
@group
/**************************************************
 * text
 *************************************************/
@end group
@end example

@vindex comment-start-skip
@example
@group
/**************************************************
    Free form text comments:
 In comments with a long delimiter line at the
 start, the indentation is kept unchanged for lines
 that start with an empty comment line prefix.  The
 delimiter line is whatever matches the
 @code{comment-start-skip} regexp.
**************************************************/
@end group
@end example

The style variable @code{c-comment-prefix-regexp} is used to recognize
the comment line prefix, e.g. the @samp{*} that usually starts every
line inside a comment.

@workswith The @code{c} syntactic symbol.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-cascaded-calls
@findex lineup-cascaded-calls (c-)
Line up ``cascaded calls'' under each other.  If the line begins with
@code{->} or @code{.} and the preceding line ends with one or more
function calls preceded by the same token, then the arrow is lined up
with the first of those tokens.  E.g:

@example
@group
r = proc->add(17)->add(18)
        ->add(19) +         @hereFn{c-lineup-cascaded-calls}
  offset;                   @hereFn{c-lineup-cascaded-calls@r{ (inactive)}}
@end group
@end example

In any other situation @code{nil} is returned to allow use in list
expressions.

@workswith @code{topmost-intro-cont}, @code{statement-cont},
@code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-close-paren
@findex lineup-close-paren (c-)
Line up the closing paren under its corresponding open paren if the
open paren is followed by code.  If the open paren ends its line, no
indentation is added.  E.g:

@example
@group
main (int,
      char **           
     )                @hereFn{c-lineup-close-paren}
@end group
@end example

@noindent
and

@example
@group
main (
    int, char **
)                     @hereFn{c-lineup-close-paren}
@end group
@end example

As a special case, if a brace block is opened at the same line as the
open parenthesis of the argument list, the indentation is
@code{c-basic-offset} instead of the open paren column.  See
@code{c-lineup-arglist} for further discussion of this ``DWIM'' measure.

@workswith All @code{*-close} symbols.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-comment
@findex lineup-comment (c-)
Line up a comment-only line according to the style variable
@code{c-comment-only-line-offset}.  If the comment is lined up with a
comment starter on the previous line, that alignment is preserved.

@defopt c-comment-only-line-offset
@vindex comment-only-line-offset (c-)
This style variable specifies the extra offset for the line.  It can
contain an integer or a cons cell of the form

@example
(@r{@var{non-anchored-offset}} . @r{@var{anchored-offset}})
@end example

@noindent
where @var{non-anchored-offset} is the amount of offset given to
non-column-zero anchored lines, and @var{anchored-offset} is the amount
of offset to give column-zero anchored lines.  Just an integer as value
is equivalent to @code{(@r{@var{value}} . -1000)}.
@end defopt

@workswith @code{comment-intro}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-cpp-define
@findex lineup-cpp-define (c-)
Line up macro continuation lines according to the indentation of the
construct preceding the macro.  E.g:

@example
@group
const char msg[] =    @hereFn{@r{The beginning of the preceding construct.}}
  \"Some text.\";

#define X(A, B)  \
do @{             \    @hereFn{c-lineup-cpp-define}
  printf (A, B); \
@} while (0)
@end group
@end example

@noindent
and:

@example
@group
int dribble() @{
  if (!running)       @hereFn{@r{The beginning of the preceding construct.}}
    error(\"Not running!\");

#define X(A, B)    \
  do @{             \  @hereFn{c-lineup-cpp-define}
    printf (A, B); \
  @} while (0)
@end group
@end example

If @code{c-syntactic-indentation-in-macros} is non-@code{nil}, the
function returns the relative indentation to the macro start line to
allow accumulation with other offsets.  E.g. in the following cases,
@code{cpp-define-intro} is combined with the
@code{statement-block-intro} that comes from the @samp{do @{} that hangs
on the @samp{#define} line:

@example
@group
const char msg[] =
  \"Some text.\";

#define X(A, B) do @{ \
  printf (A, B);     \  @hereFn{c-lineup-cpp-define}
  this->refs++;      \
@} while (0)             @hereFn{c-lineup-cpp-define}
@end group
@end example

@noindent
and:

@example
@group
int dribble() @{
  if (!running)
    error(\"Not running!\");

#define X(A, B) do @{ \
    printf (A, B);   \  @hereFn{c-lineup-cpp-define}
    this->refs++;    \
  @} while (0)           @hereFn{c-lineup-cpp-define}
@end group
@end example

The relative indentation returned by @code{c-lineup-cpp-define} is zero
and two, respectively, on the two lines in each of these examples.  They
are then added to the two column indentation that
@code{statement-block-intro} gives in both cases here.

If the relative indentation is zero, then @code{nil} is returned
instead.  That is useful in a list expression to specify the default
indentation on the top level.

If @code{c-syntactic-indentation-in-macros} is @code{nil} then this
function keeps the current indentation, except for empty lines (ignoring
the ending backslash) where it takes the indentation from the closest
preceding nonempty line in the macro.  If there's no such line in the
macro then the indentation is taken from the construct preceding it, as
described above.

@workswith @code{cpp-define-intro}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-dont-change
@findex lineup-dont-change (c-)
This lineup function makes the line stay at whatever indentation it
already has; think of it as an identity function for lineups.

@workswith Any syntactic symbol.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-gcc-asm-reg
@findex lineup-gcc-asm-reg (c-)
Line up a gcc asm register under one on a previous line.

@example
@group
    asm ("foo %1, %0\n"
         "bar %0, %1"
         : "=r" (w),
           "=r" (x)
         :  "0" (y),
            "1" (z));
@end group
@end example

The @samp{x} line is aligned to the text after the @samp{:} on the
@samp{w} line, and similarly @samp{z} under @samp{y}.

This is done only in an @samp{asm} or @samp{__asm__} block, and only to
those lines mentioned.  Anywhere else @code{nil} is returned.  The usual
arrangement is to have this routine as an extra feature at the start of
arglist lineups, e.g.

@example
(c-lineup-gcc-asm-reg c-lineup-arglist)
@end example

@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-inexpr-block
@findex lineup-inexpr-block (c-)
This can be used with the in-expression block symbols to indent the
whole block to the column where the construct is started.  E.g. for Java
anonymous classes, this lines up the class under the @samp{new} keyword,
and in Pike it lines up the lambda function body under the @samp{lambda}
keyword.  Returns @code{nil} if the block isn't part of such a
construct.

@workswith @code{inlambda}, @code{inexpr-statement},
@code{inexpr-class}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-java-inher
@findex lineup-java-inher (c-)
Line up Java implements and extends declarations.  If class names
follow on the same line as the @samp{implements}/@samp{extends}
keyword, they are lined up under each other.  Otherwise, they are
indented by adding @code{c-basic-offset} to the column of the keyword.
E.g:

@example
@group
class Foo
    extends           
        Bar           @hereFn{c-lineup-java-inher}
    @sssTBasicOffset{}
@end group
@end example

@noindent
and

@example
@group
class Foo
    extends Cyphr,
            Bar       @hereFn{c-lineup-java-inher}
@end group
@end example

@workswith @code{inher-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-java-throws
@findex lineup-java-throws (c-)
Line up Java throws declarations.  If exception names follow on the
same line as the throws keyword, they are lined up under each other.
Otherwise, they are indented by adding @code{c-basic-offset} to the
column of the @samp{throws} keyword.  The @samp{throws} keyword itself
is also indented by @code{c-basic-offset} from the function declaration
start if it doesn't hang.  E.g:

@example
@group
int foo()
    throws            @hereFn{c-lineup-java-throws}
        Bar           @hereFn{c-lineup-java-throws}
@sssTsssTBasicOffset{}
@end group
@end example

@noindent
and

@example
@group
int foo() throws Cyphr,
                 Bar,    @hereFn{c-lineup-java-throws}
                 Vlod    @hereFn{c-lineup-java-throws}
@end group
@end example

@workswith @code{func-decl-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-knr-region-comment
@findex lineup-knr-region-comment (c-)
Line up a comment in the ``K&R region'' with the declaration.  That is
the region between the function or class header and the beginning of the
block.  E.g:

@example
@group
int main()
/* Called at startup. */  @hereFn{c-lineup-knr-region-comment}
@{
  return 0;
@}
@end group
@end example

Return @code{nil} if called in any other situation, to be useful in list
expressions.

@workswith @code{comment-intro}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-math
@findex lineup-math (c-)
Line up the current line to after the equal sign on the first line in the
statement.  If there isn't any, indent with @code{c-basic-offset}.  If
the current line contains an equal sign too, try to align it with the
first one.

@workswith @code{topmost-intro-cont}, @code{statement-cont},
@code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-multi-inher
@findex lineup-multi-inher (c-)
Line up the classes in C++ multiple inheritance clauses and member
initializers under each other.  E.g:

@example
@group
Foo::Foo (int a, int b):
    Cyphr (a),
    Bar (b)           @hereFn{c-lineup-multi-inher}
@end group
@end example

@noindent
and

@example
@group
class Foo
    : public Cyphr,
      public Bar      @hereFn{c-lineup-multi-inher}
@end group
@end example

@noindent
and

@example
@group
Foo::Foo (int a, int b)
    : Cyphr (a)
    , Bar (b)         @hereFn{c-lineup-multi-inher}
@end group
@end example

@workswith @code{inher-cont}, @code{member-init-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-ObjC-method-call
@findex lineup-ObjC-method-call (c-)
For Objective-C code, line up selector args as Emacs Lisp mode does
with function args: go to the position right after the message receiver,
and if you are at the end of the line, indent the current line
c-basic-offset columns from the opening bracket; otherwise you are
looking at the first character of the first method call argument, so
lineup the current line with it.

@workswith @code{objc-method-call-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-ObjC-method-args
@findex lineup-ObjC-method-args (c-)
For Objective-C code, line up the colons that separate args.  The colon
on the current line is aligned with the one on the first line.

@workswith @code{objc-method-args-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-ObjC-method-args-2
@findex lineup-ObjC-method-args-2 (c-)
Similar to @code{c-lineup-ObjC-method-args} but lines up the colon on
the current line with the colon on the previous line.

@workswith @code{objc-method-args-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-runin-statements
@findex lineup-runin-statements (c-)
Line up statements for coding standards which place the first statement
in a block on the same line as the block opening brace@footnote{Run-in
style doesn't really work too well.  You might need to write your own
custom indentation functions to better support this style.}.  E.g:

@example
@group
int main()
@{ puts ("Hello!");
  return 0;           @hereFn{c-lineup-runin-statements}
@}
@end group
@end example

If there is no statement after the opening brace to align with,
@code{nil} is returned.  This makes the function usable in list
expressions.

@workswith The @code{statement} syntactic symbol.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-streamop
@findex lineup-streamop (c-)
Line up C++ stream operators (i.e. @samp{<<} and @samp{>>}).

@workswith @code{stream-op}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-string-cont
@findex lineup-string-cont (c-)
Line up a continued string under the one it continues.  A continued
string in this sense is where a string literal follows directly after
another one.  E.g:

@example
@group
result = prefix + "A message "
                  "string.";    @hereFn{c-lineup-string-cont}
@end group
@end example

@code{nil} is returned in other situations, to allow stacking with other
lineup functions.

@workswith @code{topmost-intro-cont}, @code{statement-cont},
@code{arglist-cont}, @code{arglist-cont-nonempty}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-template-args
@findex lineup-template-args (c-)
Line up the arguments of a template argument list under each other, but
only in the case where the first argument is on the same line as the
opening @samp{<}.

To allow this function to be used in a list expression, @code{nil} is
returned if there's no template argument on the first line.

@workswith @code{template-args-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-topmost-intro-cont
@findex lineup-topmost-intro-cont (c-)
Line up declaration continuation lines zero or one indentation
step@footnote{This function is mainly provided to mimic the behavior of
CC Mode 5.28 and earlier where this case wasn't handled consistently so
that those lines could be analyzed as either topmost-intro-cont or
statement-cont.  It's used for @code{topmost-intro-cont} by default, but
you might consider using @code{+} instead.}.  For lines preceding a
definition, zero is used.  For other lines, @code{c-basic-offset} is
added to the indentation.  E.g:

@example
@group
int
neg (int i)           @hereFn{c-lineup-topmost-intro-cont}
@{
    return -i;
@}
@end group
@end example

@noindent
and

@example
@group
struct
larch                 @hereFn{c-lineup-topmost-intro-cont}
@{
    double height;
@}
    the_larch,        @hereFn{c-lineup-topmost-intro-cont}
    another_larch;    @hereFn{c-lineup-topmost-intro-cont}
@sssTBasicOffset{}
@end group
@end example

@noindent
and

@example
@group
struct larch
the_larch,            @hereFn{c-lineup-topmost-intro-cont}
    another_larch;    @hereFn{c-lineup-topmost-intro-cont}
@end group
@end example

@workswith @code{topmost-intro-cont}.
@end defun

@comment ------------------------------------------------------------

@defun c-lineup-whitesmith-in-block
@findex lineup-whitesmith-in-block (c-)
Line up lines inside a block in Whitesmith style.  It's done in a way
that works both when the opening brace hangs and when it doesn't.  E.g:

@example
@group
something
    @{
    foo;              @hereFn{c-lineup-whitesmith-in-block}
    @}
@end group
@end example

@noindent
and

@example
@group
something @{
    foo;              @hereFn{c-lineup-whitesmith-in-block}
    @}
@sssTBasicOffset{}
@end group
@end example

In the first case the indentation is kept unchanged, in the second
@code{c-basic-offset} is added.

@workswith @code{defun-close}, @code{defun-block-intro},
@code{block-close}, @code{brace-list-close}, @code{brace-list-intro},
@code{statement-block-intro} and all @code{in*} symbols,
e.g. @code{inclass} and @code{inextern-lang}.
@end defun


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node AWK Mode, Odds and Ends, Indentation Functions, Top
@comment  node-name,  next,  previous,  up
@chapter Status of AWK Mode
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@dfn{AWK mode} existed until recently in the file @file{awk-mode.el}
as a mode derived from c-mode.  It had not been actively maintained to
keep pace with the newer @ccmode{}, and its indentation mechanism no
longer worked satisfactorally.

The current AWK mode is based around the GNU implementation,
@emph{GAWK version 3.1.0}, though it should work pretty well with any
AWK.  It has now been updated and integrated into @ccmode{} to a
substantial extent, though as yet not all the features of @ccmode{}
have been adapted to support it.

If your (X)Emacs is set up to use the old file @file{awk-mode.elc}
(which will usually be the case if you have obtained this @ccmode{}
independently of (X)Emacs itself), or if you are not sure, insert the
following form into your @file{.emacs} or @file{init.el} so that the new
AWK mode will be used instead:

@example
(autoload 'awk-mode "cc-mode" nil t)
@end example

You can check which AWK mode you are running by displaying the mode
documentation string with @kbd{C-h m} from an AWK buffer.  The newer
mode's doc string contains @code{To submit a problem report, enter
`C-c C-b'} near the top of the doc string where the older mode has
@code{This is much like C mode except ....}.

Since this newer AWK mode makes essential use of a relatively new
Emacs Lisp feature@footnote{Specifically, the @code{syntax-table} text
property.}, you need either GNU Emacs 20.1 (or later) or XEmacs 21.4
(or later) to use it.  If your Emacs version is earlier than one of
these, the older @file{awk-mode.el} will get loaded and run in place
of the AWK mode described here, even when you have put the above
@code{autoload} form into your @file{.emacs} or @file{init.el}.
Upgrading your (X)Emacs is strongly recommended if this is the case.

Here is an overview of which @ccmode{} features currently work with
AWK mode and which don't:

@table @asis
@item Indentation Engine
The @ccmode{} indentation engine fully supports AWK mode.
@xref{Indentation Engine}.

AWK mode handles code formatted in the conventional AWK fashion:
@samp{@{}s which start actions, user-defined functions, or compound
statements are placed on the same line as the associated construct; the
matching @samp{@}}s are normally placed under the start of the
respective pattern, function definition, or structured statement.
@c Add in a bit about the @samp{@}} being on the same line when the
@c contents are short.

The predefined indentation functions (@pxref{Indentation Functions})
haven't yet been adapted for AWK mode, though some of them may work
serendipitously.  There shouldn't be any problems writing custom
indentation functions for AWK mode.

The command @kbd{C-c C-q} (@code{c-indent-defun}) hasn't yet been
adapted for AWK, though in practice it works properly nearly all the
time.  Should it fail, explicitly set the region around the function
(using @kbd{C-u C-SPC}: @kbd{C-M-h} probably won't work either) then do
@kbd{C-M-\} (@code{indent-region}).

@item Font Locking
There is a single level of font locking in AWK mode, rather than the
three distinct levels the other modes have.  There are several
idiosyncrasies in AWK mode's font-locking due to the peculiarities of
the AWK language itself.  @xref{AWK Mode Font Locking}.

@item Comment Commands
@kbd{M-;} (@code{indent-for-comment}) works fine.  None of the other
@ccmode{} comment formatting commands have yet been adapted for AWK
mode.  @xref{Text Filling and Line Breaking}.

@item Movement Commands
Most of the movement commands work in AWK mode.  The most important
exceptions are @kbd{M-a} (@code{c-beginning-of-statement}) and
@kbd{M-e} (@code{c-end-of-statement}) which haven't yet been adapted.

The notion of @dfn{defun} has been augmented to include pattern-action
pairs.  See @ref{AWK Mode Defuns} for a description of commands which
work on AWK ``defuns''.

Since there is no preprocessor in AWK, the commands which move to
preprocessor directives (e.g. @code{c-up-conditional}) are meaningless
in AWK mode and are not bound in the AWK mode keymap.

@item Auto-newline Insertion and Clean-ups
Auto-newline insertion hasn't yet been adapted for AWK.  Some of the
clean-ups can actually convert good AWK code into syntactically
invalid code.

If auto-newline or its associated clean-ups are enabled generally for
the modes in @ccmode{}, you are strongly recommended to disable them
in the AWK Mode hook.  @xref{Initialising AWK Mode}.

The clean-up @code{space-before-funcall}, which is independent of
auto-newline, should never be active in AWK mode (since inserting a
space between a user function's name and its opening @samp{(} makes
the call syntactically invalid).  If necessary, this should be
disabled in the AWK Mode hook.  @xref{Initialising AWK Mode}.

@end table

@menu
* Initialising AWK Mode::
* AWK Mode Font Locking::
* AWK Mode Defuns::
@end menu


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node Initialising AWK Mode, AWK Mode Font Locking, , AWK Mode
@comment  node-name,  next,  previous,  up
@section AWK mode - What to put in your @file{.emacs} or @file{init.el}
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Much of the AWK mode initialization can, of course, be done by the
@ccmode{} general initialization procedure.  You may want to use certain
@ccmode{} features such as @code{auto-newline} and @code{clean-ups} in
the other modes, and you might thus have enabled them in a
@code{c-mode-common-hook} function, as described in @ref{Sample .emacs File}.
These features have not yet been amended for AWK mode, and far from
being useful, can be irritating in AWK mode or actually make AWK code
syntactically invalid.  Adding the following code to your
@file{.emacs} or @file{init.el} file will disable them for AWK mode.

@example
(defun my-awk-mode-hook ()
  "Disable certain @ccmode{} features which could impair AWK mode."
  (c-toggle-auto-state -1)       ; disable automatic insertions of newlines
  (if (memq 'space-before-funcall c-cleanup-list)
      (setq c-cleanup-list ; don't automatically insert a space into "foo("
            (remove 'space-before-funcall c-cleanup-list))))
(add-hook 'awk-mode-hook 'my-awk-mode-hook)
@end example

Naturally you can add your own AWK-specific customizations to this
function.  @xref{Hooks}.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node AWK Mode Font Locking, AWK Mode Defuns, Initialising AWK Mode, AWK Mode
@comment  node-name,  next,  previous,  up
@section AWK Mode Font Locking
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The general appearance of font-locking in AWK mode is much like in any
other programming mode.  @xref{Faces For Font Lock,,,elisp}.

The following faces are, however, used in a non-standard fashion in
AWK mode:

@table @asis
@item @code{font-lock-variable-name-face}
This face was intended for variable declarations.  Since variables are
not declared in AWK, this face is used instead for AWK system
variables (such as @code{NF}) and ``Special File Names'' (such as
@code{"/dev/stderr"}).

@item @code{font-lock-builtin-face} (Emacs)/@code{font-lock-preprocessor-face} (XEmacs)
This face is normally used for preprocessor directives in @ccmode{}.
There are no such things in AWK, so this face is used instead for
standard functions (such as @code{match}).

@item @code{font-lock-string-face}
As well as being used for strings, including localizable strings,
(delimited by @samp{"} and @samp{_"}), this face is also used for AWK
regular expressions (delimited by @samp{/}).

@item @code{font-lock-warning-face} (Emacs)/@code{c-invalid-face} (XEmacs)
This face highlights the following syntactically invalid AWK
constructs:

@itemize @bullet
@item
An unterminated string or regular expression.  Here the opening
delimiter (@samp{"} or @samp{/} or @samp{_"}) is displayed in
@code{font-lock-warning-face}.  This is most noticeable when typing in a
new string/regular expression into a buffer, when the warning-face
serves as a continual reminder to terminate the construct.

AWK mode fontifies unterminated strings/regular expressions
differently from other modes: Only the text up to the end of the line
is fontified as a string (escaped newlines being handled correctly),
rather than the text up to the next string quote.

@item
A space between the function name and opening parenthesis when calling
a user function.  The last character of the function name and the
opening parenthesis are highlighted.  This font-locking rule will
spuriously highlight a valid concatenation expression where an
identifier precedes a parenthesised expression.  Unfortunately.

@item
Whitespace following the @samp{\} in what otherwise looks like an
escaped newline.  The @samp{\} is highlighted.
@end itemize
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node AWK Mode Defuns,  , AWK Mode Font Locking, AWK Mode
@comment  node-name,  next,  previous,  up
@section AWK Mode Defuns
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

In AWK mode, @dfn{defun} means either a user-defined function or a
pattern-action pair.  Either the pattern or the action may be
implicit.

The beginning of a defun is recognised heuristically as, more or less,
code which begins in column zero.  Having the @samp{@{} in column zero,
as is suggested for some modes, is neither necessary nor helpful in AWK
mode.

More precisely, the beginning of a defun is code which begins in
column zero, and which isn't a closing brace, a comment, or a
continuation of the previous line.  Code is the @dfn{continuation of
the previous line} when that line is syntactically incomplete, for
example when it ends with @samp{@{} or an escaped newline.

The end of a defun is the @samp{@}} which matches the @samp{@{} (if
any) at the beginning of the action or function body, or the EOL or
@samp{;} which marks an implicit action.  Although this @samp{@}} is
usually placed in column zero, AWK mode doesn't need it to be placed
there.

@table @asis
@item @kbd{C-M-a} @code{c-awk-beginning-of-defun}
@itemx @kbd{C-M-e} @code{c-awk-end-of-defun}
@findex c-awk-beginning-of-defun
@findex awk-beginning-of-defun (c-)
@findex c-awk-end-of-defun
@findex awk-end-of-defun (c-)
Move point back to the beginning or forward to the end of the current
AWK defun.  These functions can take prefix-arguments, their
functionality being entirely equivalent to @code{beginning-of-defun}
and @code{end-of-defun}.  @xref{Moving by Defuns,,,emacs}.

@item @kbd{C-M-h} @code{c-mark-function}
This works fine with AWK defuns.  @xref{Indentation Commands}.
@end table


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Odds and Ends, Performance Issues, AWK Mode, Top
@comment node-name, next, previous, up
@chapter Odds and Ends
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The stuff that didn't fit in anywhere else is documented here.

@defopt c-require-final-newline
@vindex require-final-newline (c-)
Controls whether a final newline is ensured when the file is saved.  The
value is an association list that for each language mode specifies the
value to give to @code{require-final-newline} at mode initialization;
see that variable for details about the value.  If a language isn't
present on the association list, CC Mode won't set
@code{require-final-newline} in buffers for that language.

The default is to set @code{require-final-newline} to @code{t} in the
languages that mandates that source files should end with newlines,
i.e. C, C++ and Objective-C.
@end defopt

@defopt c-echo-syntactic-information-p
@vindex echo-syntactic-information-p (c-)
If non-@code{nil}, the syntactic analysis for the current line is shown
in the echo area when it's indented (unless
@code{c-syntactic-indentation} is @code{nil}).  That's useful when
finding out which syntactic symbols to modify to get the indentation you
want.
@end defopt

@defopt c-report-syntactic-errors
@vindex report-syntactic-errors (c-)
If non-@code{nil}, certain syntactic errors are reported with a ding and
a message, for example when an @code{else} is indented for which there
is no corresponding @code{if}.

Note however that @ccmode{} doesn't make any special effort to check for
syntactic errors; that's the job of the compiler.  The reason it can
report cases like the one above is that it can't find the correct
anchoring position to indent the line in that case.
@end defopt


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Performance Issues, Limitations and Known Bugs, Odds and Ends, Top
@comment node-name, next, previous, up
@chapter Performance Issues
@cindex performance
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@comment FIXME: (ACM, 2003/5/24).  Check whether AWK needs mentioning here.

C and its derivative languages are highly complex creatures.  Often,
ambiguous code situations arise that require @ccmode{} to scan large
portions of the buffer to determine syntactic context.  Such
pathological code can cause @ccmode{} to perform fairly badly.  This
section gives some insight in how @ccmode{} operates, how that interacts
with some coding styles, and what you can use to improve performance.

The overall goal is that @ccmode{} shouldn't be overly slow (i.e. take
more than a fraction of a second) in any interactive operation.
I.e. it's tuned to limit the maximum response time in single operations,
which sometimes is at the expense of batch-like operations like
reindenting whole blocks.  If you find that @ccmode{} gradually gets
slower and slower in certain situations, perhaps as the file grows in
size or as the macro or comment you're editing gets bigger, then chances
are that something isn't working right.  You should consider reporting
it, unless it's something that's mentioned in this section.

Because @ccmode{} has to scan the buffer backwards from the current
insertion point, and because C's syntax is fairly difficult to parse in
the backwards direction, @ccmode{} often tries to find the nearest
position higher up in the buffer from which to begin a forward scan
(it's typically an opening or closing parethesis of some kind).  The
farther this position is from the current insertion point, the slower it
gets.

@findex beginning-of-defun
@findex defun-prompt-regexp
One of the simplest things you can do to reduce scan time, is make sure
any brace that opens a top-level construct@footnote{E.g. a function in
C, or outermost class definition in C++ or Java.} always appears in the
leftmost column.  This is actually an Emacs constraint, as embodied in
the @code{beginning-of-defun} function which @ccmode{} uses heavily.  If
you hang top-level open braces on the right side of the line, then you
might want to set the variable @code{defun-prompt-regexp} to something
reasonable, however that ``something reasonable'' is difficult to
define, so @ccmode{} doesn't do it for you.

@vindex c-Java-defun-prompt-regexp
@vindex Java-defun-prompt-regexp (c-)
A special note about @code{defun-prompt-regexp} in Java mode: The common
style is to hang the opening braces of functions and classes on the
right side of the line, and that doesn't work well with the Emacs
approach.  @ccmode{} comes with a variable
@code{c-Java-defun-prompt-regexp} which tries to define a regular
expression usable for this style, but there are problems with it.  In
some cases it can cause @code{beginning-of-defun} to hang@footnote{This
has been observed in Emacs 19.34 and XEmacs 19.15.}.  For this reason,
it is not used by default, but if you feel adventurous, you can set
@code{defun-prompt-regexp} to it in your mode hook.  In any event,
setting and relying on @code{defun-prompt-regexp} will definitely slow
things down because (X)Emacs will be doing regular expression searches a
lot, so you'll probably be taking a hit either way!

@ccmode{} maintains a cache of the opening parentheses of the blocks
surrounding the point, and it adapts that cache as the point is moved
around.  That means that in bad cases it can take noticeable time to
indent a line in a new surrounding, but after that it gets fast as long
as the point isn't moved far off.  The farther the point is moved, the
less useful is the cache.  Since editing typically is done in ``chunks''
rather than on single lines far apart from each other, the cache
typically gives good performance even when the code doesn't fit the
Emacs approach to finding the defun starts.

@vindex c-enable-xemacs-performance-kludge-p
@vindex enable-xemacs-performance-kludge-p (c-)
XEmacs users can set the variable
@code{c-enable-xemacs-performance-kludge-p} to non-@code{nil}.  This
tells @ccmode{} to use XEmacs-specific built-in functions which, in some
circumstances, can locate the top-most opening brace much more quickly than
@code{beginning-of-defun}.  Preliminary testing has shown that for
styles where these braces are hung (e.g. most JDK-derived Java styles),
this hack can improve performance of the core syntax parsing routines
from 3 to 60 times.  However, for styles which @emph{do} conform to
Emacs' recommended style of putting top-level braces in column zero,
this hack can degrade performance by about as much.  Thus this variable
is set to @code{nil} by default, since the Emacs-friendly styles should
be more common (and encouraged!).  Note that this variable has no effect
in Emacs since the necessary built-in functions don't exist (in Emacs
21.3 as of this writing in May 2003).

Text properties are used to speed up skipping over syntactic whitespace,
i.e. comments and preprocessor directives.  Indenting a line after a
huge macro definition can be slow the first time, but after that the
text properties are in place and it should be fast (even after you've
edited other parts of the file and then moved back).

Font locking can be a CPU hog, especially the font locking done on
decoration level 3 which tries to be very accurate.  Note that that
level is designed to be used with a font lock support mode that only
fontifies the text that's actually shown, i.e. Lazy Lock or Just-in-time
Lock mode, so make sure you use one of them.  Fontification of a whole
buffer with some thousand lines can often take over a minute.  That is
a known weakness; the idea is that it never should happen.

The most effective way to speed up font locking is to reduce the
decoration level to 2 by setting @code{font-lock-maximum-decoration}
appropriately.  That level is designed to be as pretty as possible
without sacrificing performance.  @xref{Font Locking Preliminaries}, for
more info.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Limitations and Known Bugs, Frequently Asked Questions, Performance Issues, Top
@comment node-name, next, previous, up
@chapter Limitations and Known Bugs
@cindex limitations
@cindex bugs
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@itemize @bullet
@item
There is no way to apply auto newline settings (@pxref{Auto-newline
Insertion}) on already typed lines.  That's only a feature to ease
interactive editing.

To generalize this issue a bit: @ccmode{} is not intended to be used as
a reformatter for old code in some more or less batch-like way.  With
the exception of some functions like @code{c-indent-region}, it's only
geared to be used interactively to edit new code.  There's currently no
intention to change this goal.

If you want to reformat old code, you're probably better off using some
other tool instead, e.g. @ref{Top, , GNU indent, indent, The `indent'
Manual}, which has more powerful reformatting capabilities than
@ccmode{}.

@item
@vindex signal-error-on-buffer-boundary
XEmacs has a variable called @code{signal-error-on-buffer-boundary}.
It's used as a solution to user interface problems associated with
buffer movement and the @code{zmacs-region} deactivation on errors.
However, setting this variable to a non-default value in XEmacs 19 and
20 had the deleterious side effect of breaking many built-in primitive
functions.  @strong{Do not set this variable to @code{nil} in XEmacs
19 and 20}; you will cause serious problems in @ccmode{} and probably
other XEmacs packages!  In XEmacs 21 the effects of the variable is
limited to some functions that are only used interactively, so it's
not a problem there.
@end itemize


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Frequently Asked Questions, Getting the Latest CC Mode Release, Limitations and Known Bugs, Top
@comment node-name, next, previous, up
@appendix Frequently Asked Questions
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@itemize @bullet
@item
@kindex C-x h
@kindex C-M-\
@emph{How do I reindent the whole file?}

Visit the file and hit @kbd{C-x h} to mark the whole buffer. Then hit
@kbd{C-M-\}.

@item
@kindex C-M-q
@kindex C-M-u
@emph{How do I reindent the current block?}

First move to the brace which opens the block with @kbd{C-M-u}, then
reindent that expression with @kbd{C-M-q}.

@item
@kindex RET
@kindex C-j
@emph{Why doesn't the @kbd{RET} key indent the new line?}

Emacs' convention is that @kbd{RET} just adds a newline, and that
@kbd{C-j} adds a newline and indents it.  You can make @kbd{RET} do this
too by adding this to your @code{c-mode-common-hook}:

@example
(define-key c-mode-base-map "\C-m" 'c-context-line-break)
@end example

This is a very common question.  If you want this to be the default
behavior, don't lobby me, lobby RMS!  @t{:-)}

@item
@emph{I put @code{(c-set-offset 'substatement-open 0)} in my
@file{.emacs} file but I get an error saying that @code{c-set-offset}'s
function definition is void.  What's wrong?}

This means that @ccmode{} wasn't loaded into your Emacs session by the
time the @code{c-set-offset} call was reached, most likely because
@ccmode{} is being autoloaded.  Instead of putting the
@code{c-set-offset} line in your top-level @file{.emacs} file, put it in
your @code{c-mode-common-hook}, or simply modify @code{c-offsets-alist}
directly:

@example
(setq c-offsets-alist '((substatement-open . 0)))
@end example

@item
@kindex M-a
@kindex M-e
@emph{@kbd{M-a} and @kbd{M-e} used to move over entire balanced brace
lists, but now they move into blocks.  How do I get the old behavior
back?}

Use @kbd{C-M-f} and @kbd{C-M-b} to move over balanced brace blocks.  Use
@kbd{M-a} and @kbd{M-e} to move by statements, which will also move into
blocks.

@item
@emph{Whenever I try to indent a line or type an ``electric'' key such
as @kbd{;}, @kbd{@{}, or @kbd{@}}, I get an error that look like this:
@code{Invalid function: (macro . #[...}. What gives?}

This is a common error when @ccmode{} hasn't been compiled correctly,
especially under Emacs 19.34@footnote{Technically, it's because some
macro wasn't defined during the compilation, so the byte compiler put
in function calls instead of the macro expansions. Later, when the
interpreter tries to call the macro as a function, it shows this
(somewhat cryptic) error message.}. If you are using the standalone
@ccmode{} distribution, try recompiling it according to the instructions
in the @file{README} file.
@end itemize


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Getting the Latest CC Mode Release, Mailing Lists and Submitting Bug Reports, Frequently Asked Questions, Top
@comment node-name, next, previous, up
@appendix Getting the Latest CC Mode Release
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@ccmode{} has been standard with all versions of Emacs since 19.34 and
of XEmacs since 19.16.

@cindex web site
Due to release schedule skew, it is likely that all of these Emacsen
have old versions of @ccmode{} and so should be upgraded.  Access to the
@ccmode{} source code, as well as more detailed information on Emacsen
compatibility, etc. are all available on the web site:

@quotation
@uref{http://cc-mode.sourceforge.net/}
@end quotation


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Mailing Lists and Submitting Bug Reports, Sample .emacs File, Getting the Latest CC Mode Release, Top
@comment node-name, next, previous, up
@appendix Mailing Lists and Submitting Bug Reports
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@kindex C-c C-b
@findex c-submit-bug-report
@findex submit-bug-report (c-)
To report bugs, use the @kbd{C-c C-b} (bound to
@code{c-submit-bug-report}) command.  This provides vital information
we need to reproduce your problem.  Make sure you include a concise,
but complete code example.  Please try to boil your example down to
just the essential code needed to reproduce the problem, and include
an exact recipe of steps needed to expose the bug.  Be especially sure
to include any code that appears @emph{before} your bug example, if
you think it might affect our ability to reproduce it.

Please try to produce the problem in an Emacs instance without any
customizations loaded (i.e. start it with the @code{-q -no-site-file}
arguments).  If it works correctly there, the problem might be caused by
faulty customizations in either your own or your site configuration.  In
that case, we'd appreciate if you isolate the Emacs Lisp code that trigs
the bug and include it in your report.

@cindex bug report mailing list
Bug reports are sent to @email{bug-cc-mode@@gnu.org}.  You can also send
other questions and suggestions (kudos? @t{;-)} to that address.  It's a
mailing list which you can join or browse an archive of; see the web
site at @uref{http://cc-mode.sourceforge.net/} for further details.

@cindex announcement mailing list
If you want to get announcements of new @ccmode{} releases, send the
word @emph{subscribe} in the body of a message to
@email{cc-mode-announce-request@@lists.sourceforge.net}.  It's possible
to subscribe from the web site too.  Announcements will also be posted
to the Usenet newsgroups @code{gnu.emacs.sources}, @code{comp.emacs} and
@code{comp.emacs.xemacs}.


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Sample .emacs File, Command and Function Index, Mailing Lists and Submitting Bug Reports, Top
@comment node-name, next, previous, up
@appendix Sample .emacs file
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@example
;; Here's a sample .emacs file that might help you along the way.
;; Just copy this region and paste it into your .emacs file.  You may
;; want to change some of the actual values.

(defconst my-c-style
  '((c-tab-always-indent        . t)
    (c-comment-only-line-offset . 4)
    (c-hanging-braces-alist     . ((substatement-open after)
                                   (brace-list-open)))
    (c-hanging-colons-alist     . ((member-init-intro before)
                                   (inher-intro)
                                   (case-label after)
                                   (label after)
                                   (access-label after)))
    (c-cleanup-list             . (scope-operator
                                   empty-defun-braces
                                   defun-close-semi))
    (c-offsets-alist            . ((arglist-close . c-lineup-arglist)
                                   (substatement-open . 0)
                                   (case-label        . 4)
                                   (block-open        . 0)
                                   (knr-argdecl-intro . -)))
    (c-echo-syntactic-information-p . t))
  "My C Programming Style")

;; offset customizations not in my-c-style
(setq c-offsets-alist '((member-init-intro . ++)))

;; Customizations for all modes in CC Mode.
(defun my-c-mode-common-hook ()
  ;; add my personal style and set it for the current buffer
  (c-add-style "PERSONAL" my-c-style t)
  ;; other customizations
  (setq tab-width 8
        ;; this will make sure spaces are used instead of tabs
        indent-tabs-mode nil)
  ;; we like auto-newline and hungry-delete
  (c-toggle-auto-hungry-state 1)
  ;; key bindings for all supported languages.  We can put these in
  ;; c-mode-base-map because c-mode-map, c++-mode-map, objc-mode-map,
  ;; java-mode-map, idl-mode-map, and pike-mode-map inherit from it.
  (define-key c-mode-base-map "\C-m" 'c-context-line-break))

(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
@end example


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Command and Function Index, Variable Index, Sample .emacs File, Top
@comment node-name, next, previous, up
@unnumbered Command and Function Index
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Since most @ccmode{} commands are prepended with the string
@samp{c-}, each appears under its @code{c-@var{thing}} name and its
@code{@var{thing} (c-)} name.
@iftex
@sp 2
@end iftex
@printindex fn


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Variable Index, Concept Index, Command and Function Index, Top
@comment node-name, next, previous, up
@unnumbered Variable Index
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Since most @ccmode{} variables are prepended with the string
@samp{c-}, each appears under its @code{c-@var{thing}} name and its
@code{@var{thing} (c-)} name.
@iftex
@sp 2
@end iftex
@printindex vr


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@node    Concept Index, , Variable Index, Top
@comment node-name, next, previous, up
@unnumbered Concept Index
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@printindex cp


@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@comment Epilogue.
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@iftex
@page
@summarycontents
@contents
@end iftex

@bye

@ignore
   arch-tag: c4cab162-5e57-4366-bdce-4a9db2fc97f0
@end ignore