indent(1)indent(1)NAMEindent - indent and format a C program source file
SYNOPSISindent input-file [ output-file ] [ [ -bap | -nbap ]
[ -bacc | -nbacc ] [ -bad | -nbad ] [ -bbb | -nbbb ]
[ -bc | -nbc ] [ -bl ] [ -br ] [ -bs | -nbs ] [ -cn ]
[ -cdn ] [ -cdb | -ncdb ] [ -ce | -nce ] [ -cin ] [ -clin ] [ -dn ]
[ -din ] [ -dj | -ndj ] [ -eei | -neei ]
[ -ei | -nei ] [ -fc1 | -nfc1 ] [ -in ] [ -ip | -nip ]
[ -ln ] [ -lcn ] [ -lp | -nlp ] [ -pcs | -npcs ] [ -npro ]
[ -psl | -npsl ] [ -sc | -nsc ] [ -sob | -nsob ] [ -st ]
[ -T typename ] [ -troff ] [ -v | -nv ]
DESCRIPTIONindent is a C program formatter. It reformats the C program in the
input-file according to the switches. The switches which can be speci‐
fied 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.
-bacc,-nbacc
If -bacc is specified, a blank line is forced around every
conditional compilation block. For example, in front of
every #ifdef and after every #endif. Other blank lines sur‐
rounding these will be swallowed. Default: -nbacc.
-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 pro‐
cedure 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.
Default: -bc.
-br,-bl Specifying -bl lines up compound statements like this:
if (...)
{
code
}
Specifying -br (the default) makes them look like this:
if (...) {
code
}
-bs,-nbs
Enable (disable) the forcing of a blank after sizeof. Some peo‐
ple believe that sizeof should appear as though it were a proce‐
dure call (-nbs, the default) and some people believe that since
sizeof is an operator, it should always be treated that way and
should always have a blank after it.
-cn The column in which comments on code start.
Default: -c33.
-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
Enable (disable) 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.
Default: -cdb.
-ce,-nce
Enables (disables) forcing else's to cuddle up to the immedi‐
ately preceding `}'. Default: -ce.
-cin Sets the continuation indent to be the value of n. Continuation
lines will be indented the value of n 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 Cause 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. Default: -cli0.
-dn Control the placement of comments which are not to the right of
code. Default: -d1 means that such comments are placed one
indentation level to the left of code. Specifying -d0 lines up
these comments with the code. See the section on comment inden‐
tation below.
-din Specify the indentation, in character positions, from a declara‐
tion keyword to the following identifier. Default: -di16.
-dj,-ndj
-dj left justifies declarations. -ndj indents declarations the
same as code. Default: -ndj.
-ei,-nei
If -ei is enabled, ifs following elses will have the same inden‐
tation as the preceding if statement. If it is disabled, ifs
following elses will be indented one extra level. Default: -ei.
-eei,-neei
If -eei is specified, an extra expression indent is applied on
continuation lines of the expression part of if() and while().
These continuation lines will be indented one extra level —
twice instead of just once. This is to avoid the confusion
between the continued expression and the statement that follows
the if() or while(). Default: -neei.
-fc1,-nfc1
Enables (disables) the formatting of comments that start in col‐
umn 1. Often, comments whose leading `/' is in column 1 have
been carefully hand formatted by the programmer. In such cases,
-nfc1 should be used. Default: -fc1.
-in The number of spaces for one indentation level. The default is
one tab stop, -i8.
-ip,-nip
Enables (disables) the indentation of parameter declarations
from the left margin. Default: -ip .
-ln Maximum length of an output line with a trailing comment.
Default: -l78.
-lcn Sets the line length for block comments to n. It defaults to
being the same as the usual line length as specified with -l.
-lp,-nlp
Lines up code surrounded by parenthesis in continuation lines.
If a line has a left parenthesis which is not closed on that
line, then continuation lines will be lined up to start at the
character position just after the left parenthesis. For exam‐
ple, 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 a couple more NEWLINE characters we get:
p1 = first_procedure(second_procedure(p2,
p3),
third_procedure(p4,
p5));
This example was generated with -lp.
-npro Ignore the profile files, ./.indent.pro and ~/.indent.pro.
-pcs , -npcs
If true (-pcs) all procedure calls and declarations in the
source code will have a space inserted between the name and the
'('. Default: -npcs
-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. Default: -psl.
-sc,-nsc
Enables (disables) the placement of asterisks (`*'s) at the left
edge of all comments. Default: -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.
-stindent takes its input from the standard input, and put its out‐
put to the standard output.
-T typename
Add 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 type‐
defs — 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 is really a symptom of a
problem in C: typedef causes a syntactic change in the language
and indent cannot 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. The usual way to get a
troffed listing is with the command
indent-troff program.c | troff -mindent
-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 com‐
pletion. Default: -nv.
USAGE
You may set up your own “profile” of defaults to indent by creating a
file called .indent.pro in either your login directory or the current
directory and including whatever switches you like. An .indent.pro in
the current directory takes precedence over the one in your login
directory. If indent is run and a profile file exists, then it is read
to set up the program's defaults. Switches on the command line,
though, always override profile switches. The switches should be sepa‐
rated by SPACE, TAB, or NEWLINE characters.
Comments
Boxed 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 SPACE, TAB, or NEWLINE
characters) 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 col‐
umn, which is set by the -cn command line parameter. Otherwise, the
comment is started at n indentation levels less than where code is cur‐
rently 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 auto‐
matically extended in extreme cases.
Preprocessor lines
In general, indent leaves preprocessor lines alone. The only reformat‐
ting that it will do is to straighten up trailing comments. It leaves
imbedded comments alone. Conditional compilation (#ifdef...#endif) is
recognized and indent attempts to correctly compensate for the syntac‐
tic 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.
/*INDENT OFF*/ /*INDENT ON*/
All text between these two comments gets left alone. Therefore, when
you put source code between these comments, it will not be affected by
the reformatting.
FILES
./.indent.pro profile file
~/.indent.pro profile file
SEE ALSOtroff(1)BUGS
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.
March 1998 indent(1)
