INDENT(1) BSD General Commands Manual INDENT(1)
NAME
indent -- indent and format C program source
SYNOPSIS
indent [input_file [output_file]] [-bacc | -nbacc] [-bad | -nbad] [-bap | -nbap] [-bbb | -nbbb]
[-bc | -nbc] [-bl] [-br] [-cn] [-cdn] [-cdb | -ncdb] [-ce | -nce] [-cin] [-clin] [-dn] [-din]
[-fc1 | -nfc1] [-in] [-ip | -nip] [-ln] [-lcn] [-lp | -nlp] [-npro] [-pcs | -npcs]
[-psl | -npsl] [-sc | -nsc] [-sob | -nsob] [-st] [-troff] [-v | -nv]
DESCRIPTION
The indent utility 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.
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 surrounding such blocks 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 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. 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 If -bs is specified, a blank is forced after sizeof. Default: -nbs.
-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 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. Default: -cdb.
-ce, -nce Enables (disables) forcing `else's to cuddle up to the immediately preceding `}'.
Default: -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. Default: -cli0.
-dn Controls the placement of comments which are not to the right of code. For example,
-d1 means that such comments are placed one indentation level to the left of code.
Specifying 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. Default: -di16.
-dj, -ndj -dj left justifies declarations. -ndj indents declarations the same as code. Default:
-ndj.
-ei, -nei Enables (disables) special else-if processing. If it's enabled, an if following an
else will have the same indentation as the preceding if statement. Default: -ei.
-eei, -neei Enables (disables) extra indentation on continuation lines of the expression part of if
and while statements. These continuation lines will be indented one extra level.
Default: -neei.
-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. Default: -fc1.
-in The number of spaces for one indentation level. Default: -i8.
-ip, -nip Enables (disables) the indentation of parameter declarations from the left margin.
Default: -ip.
-ln Maximum length of an output line. Default: -l78.
-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
`('. 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.
-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 typedef - 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 lan-guage language
guage and indent can't find all instances of typedef.
-troff Causes indent to format the program for processing by troff(1). It will produce a
fancy listing in much the same spirit as vgrind(1). If the output file is not speci-fied, specified,
fied, 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. Default: -nv.
You may set up your own `profile' of defaults to indent by creating a file called .indent.pro in your
login directory and/or the current directory and including whatever switches you like. A `.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 separated by spaces, tabs or new-lines. newlines.
lines.
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 com-ment comment
ment is left unchanged, except that its indentation may be adjusted to account for the change in inden-tation indentation
tation 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 com-mand command
mand 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 peculiar-ities peculiarities
ities 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.
ENVIRONMENT
indent uses the HOME environment variable.
FILES
./.indent.pro profile file
~/.indent.pro profile file
HISTORY
The indent command appeared in 4.2BSD.
BUGS
indent has even more switches than ls(1).
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.
BSD June 29, 2004 BSD
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