NAME
indent - indent and format C program source

DESCRIPTION
Indent is a C program formatter. It reformats the C program in the
input-file according to the switches. The switches which can be
specified are described below. They may appear before or after the
file names.

NOTE: If you only specify an input-file, the formatting is done
‘in-place’, that is, the formatted file is written back into
input-file and a backup copy of input-file is written in the
current directory. If input-file is named ‘/blah/blah/file’, the
backup file is named file.BAK.

If output-file is specified, indent checks to make sure it is
different from input-file.

OPTIONS
The options listed below control the formatting style imposed by
indent.

-bad,-nbad If -bad is specified, a blank line is forced after
every block of declarations. Default: -nbad.

-bap,-nbap If -bap is specified, a blank line is forced after
every procedure body. Default: -nbap.

-bbb,-nbbb If -bbb is specified, a blank line is forced before
every block comment. Default: -nbbb.

-bc,-nbc If -bc is specified, then a newline is forced after
each comma in a declaration. -nbc turns off this
option. The default is -nbc.

-br,-bl Specifying -bl lines up compound statements like
this:

if (...)
{
code
}

Specifying -br (the default) makes them look like
this:

if (...) {
code
}

-cn The column in which comments on code start. The
default is 33.

-cdn The column in which comments on declarations start.
The default is for these comments to start in the
same column as those on code.

-cdb,-ncdb Enables (disables) the placement of comment
delimiters on blank lines. With this option
enabled, comments look like this:

/*
* this is a comment
*/

Rather than like this:
/* this is a comment */
This only affects block comments, not comments to
the right of code. The default is -cdb.

-ce,-nce Enables (disables) forcing ‘else’s to cuddle up to
the immediately preceding ‘}’. The default is -ce.

-cin Sets the continuation indent to be n. Continuation
lines will be indented that far from the beginning
of the first line of the statement. Parenthesized
expressions have extra indentation added to indicate
the nesting, unless -lp is in effect. -ci defaults
to the same value as -i.

-clin Causes case labels to be indented n tab stops to the
right of the containing switch statement. -cli0.5
causes case labels to be indented half a tab stop.
The default is -cli0. (This is the only option that
takes a fractional argument.)

-dn Controls the placement of comments which are not to
the right of code. Specifying -d1 means that such
comments are placed one indentation level to the
left of code. The default -d0 lines up these
comments with the code. See the section on comment
indentation below.

-din Specifies the indentation, in character positions,
from a declaration keyword to the following
identifier. The default is -di16.

-dj,-ndj -dj left justifies declarations. -ndj indents
declarations the same as code. The default is -ndj.

-ei,-nei Enables (disables) special else-if processing. If
enabled, ifs following elses will have the same
indentation as the preceding if statement. The
default is -ei.

-fc1,-nfc1 Enables (disables) the formatting of comments that
start in column 1. Often, comments whose leading
‘/’ is in column 1 have been carefully hand
formatted by the programmer. In such cases, -nfc1
should be used. The default is -fc1.

-in The number of spaces for one indentation level. The
default is 8.

-ip,-nip Enables (disables) the indentation of parameter
declarations from the left margin. The default is
-ip.

-ln Maximum length of an output line. The default is
78.

-lp,-nlp Lines up code surrounded by parenthesis in
continuation lines. If a line has a left paren
which is not closed on that line, then continuation
lines will be lined up to start at the character
position just after the left paren. For example,
here is how a piece of continued code looks with
-nlp in effect:

p1 = first_procedure(second_procedure(p2, p3),
third_procedure(p4, p5));

With -lp in effect (the default) the code looks
somewhat clearer:
p1 = first_procedure(second_procedure(p2, p3),
third_procedure(p4, p5));

Inserting two more newlines we get:
p1 = first_procedure(second_procedure(p2,
p3),
third_procedure(p4,
p5));

-npro Causes the profile files, ‘./.indent.pro’ and
‘~/.indent.pro’, to be ignored.

-pcs,-npcs If true (-pcs) all procedure calls will have a space
inserted between the name and the ‘(’. The default
is -npcs.

-ps,-nps If true (-ps) the pointer following operator ‘->’
will be surrounded by spaces on either side. The
default is -nps.

-psl,-npsl If true (-psl) the names of procedures being defined
are placed in column 1 - their types, if any, will
be left on the previous lines. The default is -psl.

-sc,-nsc Enables (disables) the placement of asterisks (‘*’s)
at the left edge of all comments. The default is
-sc.

-sob,-nsob If -sob is specified, indent will swallow optional
blank lines. You can use this to get rid of blank
lines after declarations. Default: -nsob.

-st Causes indent to take its input from stdin, and put
its output to stdout.

-Ttypename Adds typename to the list of type keywords. Names
accumulate: -T can be specified more than once. You
need to specify all the typenames that appear in
your program that are defined by typedefs - nothing
will be harmed if you miss a few, but the program
won’t be formatted as nicely as it should. This
sounds like a painful thing to have to do, but it’s
really a symptom of a problem in C: typedef causes a
syntactic change in the language and indent can’t
find all typedefs.

-troff Causes indent to format the program for processing
by troff. It will produce a fancy listing in much
the same spirit as vgrind. If the output file is
not specified, the default is standard output,
rather than formatting in place.

-v,-nv -v turns on ‘verbose’ mode; -nv turns it off. When
in verbose mode, indent reports when it splits one
line of input into two or more lines of output, and
gives some size statistics at completion. The
default is -nv.

FURTHER DESCRIPTION
You may set up your own ‘profile’ of defaults to indent by creating
a file called .indent.pro in either your login directory and/or the
current directory and including whatever switches you like.
Switches in ‘.indent.pro’ in the current directory override those
in your login directory (with the exception of -T type definitions,
which just accumulate). If indent is run and a profile file
exists, then it is read to set up the program’s defaults. The
switches should be separated by spaces, tabs or newlines. Switches
on the command line, however, override profile switches.

Comments

‘Box’ comments. Indent assumes that any comment with a dash or
star immediately after the start of comment (that is, ‘/*-’ or
‘/**’) is a comment surrounded by a box of stars. Each line of
such a comment is left unchanged, except that its indentation may
be adjusted to account for the change in indentation of the first
line of the comment.

Straight text. All other comments are treated as straight text.
Indent fits as many words (separated by blanks, tabs, or newlines)
on a line as possible. Blank lines break paragraphs.

Comment indentation

If a comment is on a line with code it is started in the ‘comment
column’, which is set by the -cn command line parameter.
Otherwise, the comment is started at n indentation levels less than
where code is currently being placed, where n is specified by the
-dn command line parameter. If the code on a line extends past the
comment column, the comment starts further to the right, and the
right margin may be automatically extended in extreme cases.

Preprocessor lines

In general, indent leaves preprocessor lines alone. The only
reformatting that it will do is to straighten up trailing comments.
It leaves embedded comments alone. Conditional compilation
(#ifdef...#endif) is recognized and indent attempts to correctly
compensate for the syntactic peculiarities introduced.

C syntax

Indent understands a substantial amount about the syntax of C, but
it has a ‘forgiving’ parser. It attempts to cope with the usual
sorts of incomplete and misformed syntax. In particular, the use
of macros like:
#define forever for(;;)
is handled properly.

FILES
./.indent.pro profile file
~/.indent.pro profile file

BUGS
Indent has even more switches than ls.

A common mistake that often causes grief is typing:
indent *.c
to the shell in an attempt to indent all the C programs in a
directory. This is probably a bug, not a feature.