indent
INDENT(1L) INDENT(1L)
NAME
indent - changes the appearance of a C program by insert
ing or deleting whitespace.
SYNOPSIS
indent [options] [input-files]
indent [options] [single-input-file] [-o output-file]
indent --version
DESCRIPTION
This man page is generated from the file indent.texinfo.
This is Edition of "The indent Manual", for Indent Ver
sion , last updated .
The indent program can be used to make code easier to
read. It can also convert from one style of writing C to
another.
indent understands a substantial amount about the syntax
of C, but it also attempts to cope with incomplete and
misformed syntax.
In version 1.2 and more recent versions, the GNU style of
indenting is the default.
OPTIONS
-bad, --blank-lines-after-declarations
Force blank lines after the declarations.
See BLANK LINES.
-bap, --blank-lines-after-procedures
Force blank lines after procedure bodies.
See BLANK LINES.
-bbb, --blank-lines-before-block-comments
Force blank lines before block comments.
See BLANK LINES.
-bbo, --break-before-boolean-operator
Prefer to break long lines before boolean operators.
See BREAKING LONG LINES.
-bc, --blank-lines-after-commas
Force newline after comma in declaration.
See DECLARATIONS.
-bl, --braces-after-if-line
Put braces on line after if, etc.
See STATEMENTS.
-blin, --brace-indentn
Indent braces n spaces.
See STATEMENTS.
-bls, --braces-after-struct-decl-line
Put braces on the line after struct declaration lines.
See DECLARATIONS.
-br, --braces-on-if-line
Put braces on line with if, etc.
See STATEMENTS.
-brs, --braces-on-struct-decl-line
Put braces on struct declaration line.
See DECLARATIONS.
-bs, --Bill-Shannon, --blank-before-sizeof
Put a space between sizeof and its argument.
See STATEMENTS.
-cn, --comment-indentationn
Put comments to the right of code in column n.
See COMMENTS.
-cbin, --case-brace-indentationn
Indent braces after a case label N spaces.
See STATEMENTS.
-cdn, --declaration-comment-columnn
Put comments to the right of the declarations in col
umn n.
See COMMENTS.
-cdb, --comment-delimiters-on-blank-lines
Put comment delimiters on blank lines.
See COMMENTS.
-cdw, --cuddle-do-while
Cuddle while of do {} while; and preceeding `}´.
See COMMENTS.
-ce, --cuddle-else
Cuddle else and preceeding `}´.
See COMMENTS.
-cin, --continuation-indentationn
Continuation indent of n spaces.
See STATEMENTS.
-clin, --case-indentationn
Case label indent of n spaces.
See STATEMENTS.
-cpn, --else-endif-columnn
Put comments to the right of #else and #endif state
ments in column n.
See COMMENTS.
-cs, --space-after-cast
Put a space after a cast operator.
See STATEMENTS.
-dn, --line-comments-indentationn
Set indentation of comments not to the right of code
to n spaces.
See COMMENTS.
-bfda, --break-function-decl-args
Align all arguments in a declaration with opening
paren.
See DECLARATIONS.
-din, --declaration-indentationn
Put variables in column n.
See DECLARATIONS.
-fc1, --format-first-column-comments
Format comments in the first column.
See COMMENTS.
-fca, --format-all-comments
Do not disable all formatting of comments.
See COMMENTS.
-gnu, --gnu-style
Use GNU coding style. This is the default.
See COMMON STYLES.
-hnl, --honour-newlines
Prefer to break long lines at the position of newlines
in the input.
See BREAKING LONG LINES.
-in, --indent-leveln
Set indentation level to n spaces.
See INDENTATION.
-ipn, --parameter-indentationn
Indent parameter types in old-style function defini
tions by n spaces.
See INDENTATION.
-kr, --k-and-r-style
Use Kernighan & Ritchie coding style.
See COMMON STYLES.
-ln, --line-lengthn
Set maximum line length for non-comment lines to n.
See BREAKING LONG LINES.
-lcn, --comment-line-lengthn
Set maximum line length for comment formatting to n.
See COMMENTS.
-lp, --continue-at-parentheses
Line up continued lines at parentheses.
See INDENTATION.
-lps, --leave-preprocessor-space
Leave space between `#´ and preprocessor directive.
See INDENTATION.
-nbad, --no-blank-lines-after-declarations
Do not force blank lines after declarations.
See BLANK LINES.
-nbap, --no-blank-lines-after-procedures
Do not force blank lines after procedure bodies.
See BLANK LINES.
-nbbo, --break-after-boolean-operator
Do not prefer to break long lines before boolean oper
ators.
See BREAKING LONG LINES.
-nbc, --no-blank-lines-after-commas
Do not force newlines after commas in declarations.
See DECLARATIONS.
-nbfda, --dont-break-function-decl-args
Don´t put each argument in a function declaration on a
seperate line.
See DECLARATIONS.
-ncdb, --no-comment-delimiters-on-blank-lines
Do not put comment delimiters on blank lines.
See COMMENTS.
-ncdw, --dont-cuddle-do-while
Do not cuddle } and the while of a do {} while;.
See STATEMENTS.
-nce, --dont-cuddle-else
Do not cuddle } and else.
See STATEMENTS.
-ncs, --no-space-after-casts
Do not put a space after cast operators.
See STATEMENTS.
-nfc1, --dont-format-first-column-comments
Do not format comments in the first column as normal.
See COMMENTS.
-nfca, --dont-format-comments
Do not format any comments.
See COMMENTS.
-nhnl, --ignore-newlines
Do not prefer to break long lines at the position of
newlines in the input.
See BREAKING LONG LINES.
-nip, --no-parameter-indentation
Zero width indentation for parameters.
See INDENTATION.
-nlp, --dont-line-up-parentheses
Do not line up parentheses.
See STATEMENTS.
-npcs, --no-space-after-function-call-names
Do not put space after the function in function calls.
See STATEMENTS.
-nprs, --no-space-after-parentheses
Do not put a space after every ´(´ and before every
´)´.
See STATEMENTS.
-npsl, --dont-break-procedure-type
Put the type of a procedure on the same line as its
name.
See DECLARATIONS.
-nsaf, --no-space-after-for
Do not put a space after every for.
See STATEMENTS.
-nsai, --no-space-after-if
Do not put a space after every if.
See STATEMENTS.
-nsaw, --no-space-after-while
Do not put a space after every while.
See STATEMENTS.
-nsc, --dont-star-comments
Do not put the `*´ character at the left of comments.
See COMMENTS.
-nsob, --leave-optional-blank-lines
Do not swallow optional blank lines.
See BLANK LINES.
-nss, --dont-space-special-semicolon
Do not force a space before the semicolon after cer
tain statements. Disables `-ss´.
See STATEMENTS.
-nut, --no-tabs
Use spaces instead of tabs.
See INDENTATION.
-nv, --no-verbosity
Disable verbose mode.
See MISCELLANEOUS OPTIONS.
-orig, --original
Use the original Berkeley coding style.
See COMMON STYLES.
-npro, --ignore-profile
Do not read `.indent.pro´ files.
See INVOKING INDENT.
-pcs, --space-after-procedure-calls
Insert a space between the name of the procedure being
called and the `(´.
See STATEMENTS.
-pin, --paren-indentationn
Specify the extra indentation per open parentheses ´(´
when a statement is broken.See STATEMENTS.
-pmt, --preserve-mtime
Preserve access and modification times on output
files.See MISCELLANEOUS OPTIONS.
-prs, --space-after-parentheses
Put a space after every ´(´ and before every ´)´.
See STATEMENTS.
-psl, --procnames-start-lines
Put the type of a procedure on the line before its
name.
See DECLARATIONS.
-saf, --space-after-for
Put a space after each for.
See STATEMENTS.
-sai, --space-after-if
Put a space after each if.
See STATEMENTS.
-saw, --space-after-while
Put a space after each while.
See STATEMENTS.
-sbin, --struct-brace-indentationn
Indent braces of a struct, union or enum N spaces.
See STATEMENTS.
-sc, --start-left-side-of-comments
Put the `*´ character at the left of comments.
See COMMENTS.
-sob, --swallow-optional-blank-lines
Swallow optional blank lines.
See BLANK LINES.
-ss, --space-special-semicolon
On one-line for and while statments, force a blank
before the semicolon.
See STATEMENTS.
-st, --standard-output
Write to standard output.
See INVOKING INDENT.
-T Tell indent the name of typenames.
See DECLARATIONS.
-tsn, --tab-sizen
Set tab size to n spaces.
See INDENTATION.
-ut, --use-tabs
Use tabs. This is the default.
See INDENTATION.
-v, --verbose
Enable verbose mode.
See MISCELLANEOUS OPTIONS.
-version
Output the version number of indent.
See MISCELLANEOUS OPTIONS.
INVOKING INDENT
As of version 1.3, the format of the indent command is:
indent [options] [input-files]
indent [options] [single-input-file] [-o output-file]
This format is different from earlier versions and other
versions of indent.
In the first form, one or more input files are specified.
indent makes a backup copy of each file, and the original
file is replaced with its indented version. See
BACKUP FILES, for an explanation of how backups are made.
In the second form, only one input file is specified. In
this case, or when the standard input is used, you may
specify an output file after the `-o´ option.
To cause indent to write to standard output, use the `-st´
option. This is only allowed when there is only one input
file, or when the standard input is used.
If no input files are named, the standard input is read
for input. Also, if a filename named `-´ is specified,
then the standard input is read.
As an example, each of the following commands will input
the program `slithy_toves.c´ and write its indented text
to `slithy_toves.out´:
indent slithy_toves.c -o slithy_toves.out
indent -st slithy_toves.c > slithy_toves.out
cat slithy_toves.c | indent -o slithy_toves.out
Most other options to indent control how programs are for
matted. As of version 1.2, indent also recognizes a long
name for each option name. Long options are prefixed by
either `--´ or `+´. [ `+´ is being superseded by `--´ to
maintain consistency with the POSIX standard.] In most of
this document, the traditional, short names are used for
the sake of brevity. See OPTION SUMMARY, for a list of
options, including both long and short names.
Here is another example:
indent -br test/metabolism.c -l85
This will indent the program `test/metabolism.c´ using the
`-br´ and `-l85´ options, write the output back to
`test/metabolism.c´, and write the original contents of
`test/metabolism.c´ to a backup file in the directory
`test´.
Equivalent invocations using long option names for this
example would be:
indent --braces-on-if-line --line-length185 test/metabolism.c
indent +braces-on-if-line +line-length185 test/metabolism.c
If you find that you often use indent with the same
options, you may put those options into a file named
`.indent.pro´. indent will first look for `.indent.pro´
in the current directory and use that if found. Other
wise, indent will search your home directory for
`.indent.pro´ and use that file if it is found. This
behaviour is different from that of other versions of
indent, which load both files if they both exist.
The format of `.indent.pro´ is simply a list of options,
just as they would appear on the command line, separated
by white space (tabs, spaces, and newlines). Options in
`.indent.pro´ may be surrounded by C or C++ comments, in
which case they are ignored.
Command line switches are handled after processing
`.indent.pro´. Options specified later override arguments
specified earlier, with one exception: Explicitly speci
fied options always override background options (See COM
MON STYLES). You can prevent indent from reading an
`.indent.pro´ file by specifying the `-npro´ option.
BACKUPFILES
As of version 1.3, GNU indent makes GNU-style backup
files, the same way GNU Emacs does. This means that
either simple or numbered backup filenames may be made.
Simple backup file names are generated by appending a suf
fix to the original file name. The default for this suf
fix is the one-character string `~´ (tilde). Thus, the
backup file for `python.c´ would be `python.c~´.
Instead of the default, you may specify any string as a
suffix by setting the environment variable SIM
PLE_BACKUP_SUFFIX to your preferred suffix.
Numbered backup versions of a file `momeraths.c´ look like
`momeraths.c.~23~´, where 23 is the version of this par
ticular backup. When making a numbered backup of the file
`src/momeraths.c´, the backup file will be named
`src/momeraths.c.~V~´, where V is one greater than the
highest version currently existing in the directory `src´.
The environment variable VERSION_WIDTH controls the number
of digits, using left zero padding when necessary. For
instance, setting this variable to "2" will lead to the
backup file being named `momeraths.c.~04~´.
The type of backup file made is controlled by the value of
the environment variable VERSION_CONTROL. If it is the
string `simple´, then only simple backups will be made.
If its value is the string `numbered´, then numbered back
ups will be made. If its value is `numbered-existing´,
then numbered backups will be made if there already exist
numbered backups for the file being indented; otherwise, a
simple backup is made. If VERSION_CONTROL is not set,
then indent assumes the behaviour of `numbered-existing´.
Other versions of indent use the suffix `.BAK´ in naming
backup files. This behaviour can be emulated by setting
SIMPLE_BACKUP_SUFFIX to `.BAK´.
Note also that other versions of indent make backups in
the current directory, rather than in the directory of the
source file as GNU indent now does.
COMMON STYLES
There are several common styles of C code, including the
GNU style, the Kernighan & Ritchie style, and the original
Berkeley style. A style may be selected with a single
background option, which specifies a set of values for all
other options. However, explicitly specified options
always override options implied by a background option.
As of version 1.2, the default style of GNU indent is the
GNU style. Thus, it is no longer necessary to specify the
option `-gnu´ to obtain this format, although doing so
will not cause an error. Option settings which correspond
to the GNU style are:
-nbad -bap -nbc -bbo -bl -bli2 -bls -ncdb -nce -cp1 -cs -di2
-ndj -nfc1 -nfca -hnl -i2 -ip5 -lp -pcs -nprs -psl -saf -sai
-saw -nsc -nsob
The GNU coding style is that preferred by the GNU project.
It is the style that the GNU Emacs C mode encourages and
which is used in the C portions of GNU Emacs. (People
interested in writing programs for Project GNU should get
a copy of "The GNU Coding Standards", which also covers
semantic and portability issues such as memory usage, the
size of integers, etc.)
The Kernighan & Ritchie style is used throughout their
well-known book "The C Programming Language". It is
enabled with the `-kr´ option. The Kernighan & Ritchie
style corresponds to the following set of options:
-nbad -bap -bbo -nbc -br -brs -c33 -cd33 -ncdb -ce -ci4 -cli0
-cp33 -cs -d0 -di1 -nfc1 -nfca -hnl -i4 -ip0 -l75 -lp -npcs
-nprs -npsl -saf -sai -saw -nsc -nsob -nss
Kernighan & Ritchie style does not put comments to the
right of code in the same column at all times (nor does it
use only one space to the right of the code), so for this
style indent has arbitrarily chosen column 33.
The style of the original Berkeley indent may be obtained
by specifying `-orig´ (or by specifying `--original´,
using the long option name). This style is equivalent to
the following settings:
-nbad -nbap -bbo -bc -br -brs -c33 -cd33 -cdb -ce -ci4 -cli0
-cp33 -di16 -fc1 -fca -hnl -i4 -ip4 -l75 -lp -npcs -nprs -psl
-saf -sai -saw -sc -nsob -nss -ts8
BLANK LINES
Various programming styles use blank lines in different
places. indent has a number of options to insert or
delete blank lines in specific places.
The `-bad´ option causes indent to force a blank line
after every block of declarations. The `-nbad´ option
causes indent not to force such blank lines.
The `-bap´ option forces a blank line after every proce
dure body. The `-nbap´ option forces no such blank line.
The `-bbb´ option forces a blank line before every boxed
comment, See COMMENTS. The `-nbbb´ option does not force
such blank lines.
The `-sob´ option causes indent to swallow optional blank
lines (that is, any optional blank lines present in the
input will be removed from the output). If the `-nsob´ is
specified, any blank lines present in the input file will
be copied to the output file.
--blank-lines-after-declarations
The `-bad´ option forces a blank line after every block of
declarations. The `-nbad´ option does not add any such
blank lines.
For example, given the input
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
indent -bad produces
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
and indent -nbad produces
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
--blank-lines-after-procedures
The `-bap´ option forces a blank line after every proce
dure body.
For example, given the input
int
foo ()
{
puts("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts("Hello");
}
indent -bap produces
int
foo ()
{
puts ("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts ("Hello");
}
and indent -nbap produces
int
foo ()
{
puts ("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts ("Hello");
}
No blank line will be added after the procedure foo.
COMMENTS
indent formats both C and C++ comments. C comments are
begun with `/*´, terminated with `*/´ and may contain new
line characters. C++ comments begin with the delimiter
`//´ and end at the newline.
indent handles comments differently depending upon their
context. indent attempts to distinguish between comments
which follow statements, comments which follow declara
tions, comments following preprocessor directives, and
comments which are not preceded by code of any sort, i.e.,
they begin the text of the line (although not neccessarily
in column 1).
indent further distinguishes between comments found out
side of procedures and aggregates, and those found within
them. In particular, comments beginning a line found
within a procedure will be indented to the column at which
code is currently indented. The exception to this a com
ment beginning in the leftmost column; such a comment is
output at that column.
indent attempts to leave boxed comments unmodified. The
general idea of such a comment is that it is enclosed in a
rectangle or ``box´´ of stars or dashes to visually set it
apart. More precisely, boxed comments are defined as
those in which the initial `/*´ is followed immediately by
the character `*´, `=´, `_´, or `-´, or those in which the
beginning comment delimiter (`/*´) is on a line by itself,
and the following line begins with a `*´ in the same col
umn as the star of the opening delimiter.
Examples of boxed comments are:
/**********************
* Comment in a box!! *
**********************/
/*
* A different kind of scent,
* for a different kind of comment.
*/
indent attempts to leave boxed comments exactly as they
are found in the source file. Thus the indentation of the
comment is unchanged, and its length is not checked in any
way. The only alteration made is that an embedded tab
character may be converted into the appropriate number of
spaces.
If the `-bbb´ option is specified, all such boxed comments
will be preceded by a blank line, unless such a comment is
preceded by code.
Comments which are not boxed comments may be formatted,
which means that the line is broken to fit within a right
margin and left-filled with whitespace. Single newlines
are equivalent to a space, but blank lines (two or more
newlines in a row) are taken to mean a paragraph break.
Formatting of comments which begin after the first column
is enabled with the `-fca´ option. To format those begin
ning in column one, specify `-fc1´. Such formatting is
disabled by default.
The right margin for formatting defaults to 78, but may be
changed with the `-lc´ option. If the margin specified
does not allow the comment to be printed, the margin will
be automatically extended for the duration of that com
ment. The margin is not respected if the comment is not
being formatted.
If the comment begins a line (i.e., there is no program
text to its left), it will be indented to the column it
was found in unless the comment is within a block of code.
In that case, such a comment will be aligned with the
indented code of that block (unless the comment began in
the first column). This alignment may be affected by the
`-d´ option, which specifies an amount by which such com
ments are moved to the left, or unindented. For example,
`-d2´ places comments two spaces to the left of code. By
default, comments are aligned with code, unless they begin
in the first column, in which case they are left there by
default --- to get them aligned with the code, specify
`-fc1´.
Comments to the right of code will appear by default in
column 33. This may be changed with one of three options.
`-c´ will specify the column for comments following code,
`-cd´ specifies the column for comments following declara
tions, and `-cp´ specifies the column for comments follow
ing preprocessor directives #else and #endif.
If the code to the left of the comment exceeds the begin
ning column, the comment column will be extended to the
next tabstop column past the end of the code, or in the
case of preprocessor directives, to one space past the end
of the directive. This extension lasts only for the out
put of that particular comment.
The `-cdb´ option places the comment delimiters on blank
lines. Thus, a single line comment like /* Loving hug */
can be transformed into:
/*
Loving hug
*/
Stars can be placed at the beginning of multi-line com
ments with the `-sc´ option. Thus, the single-line com
ment above can be transformed (with `-cdb -sc´) into:
/*
* Loving hug
*/
STATEMENTS
The `-br´ or `-bl´ option specifies how to format braces.
The `-br´ option formats statement braces like this:
if (x > 0) {
x--;
}
The `-bl´ option formats them like this:
if (x > 0)
{
x--;
}
If you use the `-bl´ option, you may also want to specify
the `-bli´ option. This option specifies the number of
spaces by which braces are indented. `-bli2´, the
default, gives the result shown above. `-bli0´ results in
the following:
if (x > 0)
{
x--;
}
If you are using the `-br´ option, you probably want to
also use the `-ce´ option. This causes the else in an if-
then-else construct to cuddle up to the immediately pre
ceding `}´. For example, with `-br -ce´ you get the fol
lowing:
if (x > 0) {
x--;
} else {
fprintf (stderr, "...something wrong?\n");
}
With `-br -nce´ that code would appear as
if (x > 0) {
x--;
}
else {
fprintf (stderr, "...something wrong?\n");
}
This causes the while in a do-while loop to cuddle up to
the immediately preceding `}´. For example, with `-cdw´
you get the following:
do {
x--;
} while (x);
With `-ncdw´ that code would appear as
do {
x--;
}
while (x);
The `-cli´ option specifies the number of spaces that case
labels should be indented to the right of the containing
switch statement.
The default gives code like:
switch (i)
{
case 0:
break;
case 1:
{
++i;
}
default:
break;
}
Using the `-cli2´ that would become:
switch (i)
{
case 0:
break;
case 1:
{
++i;
}
default:
break;
}
The indentation of the braces below a case statement can
be controlled with the `-cbin´ option. For example, using
`-cli2 -cbi0´ results in:
switch (i)
{
case 0:
break;
case 1:
{
++i;
}
default:
break;
}
If a semicolon is on the same line as a for or while
statement, the `-ss´ option will cause a space to be
placed before the semicolon. This emphasizes the semi
colon, making it clear that the body of the for or while
statement is an empty statement. `-nss´ disables this
feature.
The `-pcs´ option causes a space to be placed between the
name of the procedure being called and the `(´ (for exam
ple, puts ("Hi");. The `-npcs´ option would give
puts("Hi");).
If the `-cs´ option is specified, indent puts a space
after a cast operator.
The `-bs´ option ensures that there is a space between the
keyword sizeof and its argument. In some versions, this
is known as the `Bill_Shannon´ option.
The `-saf´ option forces a space between an for and the
following parenthesis. This is the default.
The `-sai´ option forces a space between an if and the
following parenthesis. This is the default.
The `-saw´ option forces a space between an while and the
following parenthesis. This is the default.
The `-prs´ option causes all parentheses to be seperated
with a space from the what is between them. For example,
using `-prs´ results in code like:
while ( ( e_code - s_code ) < ( dec_ind - 1 ) )
{
set_buf_break ( bb_dec_ind );
*e_code++ = ´ ´;
}
DECLARATIONS
By default indent will line up identifiers, in the column
specified by the `-di´ option. For example, `-di16´ makes
things look like:
int foo;
char *bar;
Using a small value (such as one or two) for the `-di´
option can be used to cause the identifiers to be placed
in the first available position; for example:
int foo;
char *bar;
The value given to the `-di´ option will still affect
variables which are put on separate lines from their
types, for example `-di2´ will lead to:
int
foo;
If the `-bc´ option is specified, a newline is forced
after each comma in a declaration. For example,
int a,
b,
c;
With the `-nbc´ option this would look like
int a, b, c;
The `-bfda´ option causes a newline to be forced after the
comma separating the arguments of a function declaration.
The arguments will appear at the current indention level
matching the opening paren. This is particularly helpful
for functions with long argument lists. For example,
void foo (int arg1, char arg2, int *arg3, long arg4, char arg5);
With the `-bfda´ option this would look like
void foo (int arg1,
char arg2,
int *arg3,
long arg4,
char arg5);
The `-psl´ option causes the type of a procedure being
defined to be placed on the line before the name of the
procedure. This style is required for the etags program
to work correctly, as well as some of the c-mode functions
of Emacs.
You must use the `-T´ option to tell indent the name of
all the typenames in your program that are defined by
typedef. `-T´ can be specified more than once, and all
names specified are used. For example, if your program
contains
typedef unsigned long CODE_ADDR;
typedef enum {red, blue, green} COLOR;
you would use the options `-T CODE_ADDR -T COLOR´.
The `-brs´ or `-bls´ option specifies how to format braces
in struct declarations. The `-brs´ option formats braces
like this:
struct foo {
int x;
};
The `-bls´ option formats them like this:
struct foo
{
int x;
};
INDENTATION
One issue in the formatting of code is how far each line
should be indented from the left margin. When the begin
ning of a statement such as if or for is encountered, the
indentation level is increased by the value specified by
the `-i´ option. For example, use `-i8´ to specify an
eight character indentation for each level. When a state
ment is broken across two lines, the second line is
indented by a number of additional spaces specified by the
`-ci´ option. `-ci´ defaults to 0. However, if the `-lp´
option is specified, and 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. This processing also applies
to `[´ and applies to `{´ when it occurs in initialization
lists. For example, a piece of continued code might look
like this with `-nlp -ci3´ in effect:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
With `-lp´ in effect the code looks somewhat clearer:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
When a statement is broken in between two or more paren
pairs (...), each extra pair causes the indentation level
extra indentation:
if ((((i < 2 &&
k > 0) || p == 0) &&
q == 1) ||
n = 0)
The option `-ipN´ can be used to set the extra offset per
paren. For instance, `-ip0´ would format the above as:
if ((((i < 2 &&
k > 0) || p == 0) &&
q == 1) ||
n = 0)
indent assumes that tabs are placed at regular intervals
of both input and output character streams. These inter
vals are by default 8 columns wide, but (as of version
1.2) may be changed by the `-ts´ option. Tabs are treated
as the equivalent number of spaces.
The indentation of type declarations in old-style function
definitions is controlled by the `-ip´ parameter. This is
a numeric parameter specifying how many spaces to indent
type declarations. For example, the default `-ip5´ makes
definitions look like this:
char *
create_world (x, y, scale)
int x;
int y;
float scale;
{
. . .
}
For compatibility with other versions of indent, the
option `-nip´ is provided, which is equivalent to `-ip0´.
ANSI C allows white space to be placed on preprocessor
command lines between the character `#´ and the command
name. By default, indent removes this space, but specify
ing the `-lps´ option directs indent to leave this space
unmodified.
BREAKING LONG LINES
With the option `-ln´, or `--line-lengthn´, it is possible
to specify the maximum length of a line of C code, not
including possible comments that follow it.
When lines become longer then the specified line length,
GNU indent tries to break the line at a logical place.
This is new as of version 2.1 however and not very intel
ligent or flexible yet.
Currently there are two options that allows one to inter
fere with the algorithm that determines where to break a
line.
The `-bbo´ option causes GNU indent to prefer to break
long lines before the boolean operators && and ||. The
`-nbbo´ option causes GNU indent not have that preference.
For example, the default option `-bbo´ (together with
`--line-length60´ and `--ignore-newlines´) makes code look
like this:
if (mask
&& ((mask[0] == ´\0´)
|| (mask[1] == ´\0´
&& ((mask[0] == ´0´) || (mask[0] == ´*´)))))
Using the option `-nbbo´ will make it look like this:
if (mask &&
((mask[0] == ´\0´) ||
(mask[1] == ´\0´ &&
((mask[0] == ´0´) || (mask[0] == ´*´)))))
The default `-hnl´, however, honours newlines in the input
file by giving them the highest possible priority to break
lines at. For example, when the input file looks like
this:
if (mask
&& ((mask[0] == ´\0´)
|| (mask[1] == ´\0´ && ((mask[0] == ´0´) || (mask[0] == ´*´)))))
then using the option `-hnl´, or `--honour-newlines´,
together with the previously mentioned `-nbbo´ and
`--line-length60´, will cause the output not to be what is
given in the last example but instead will prefer to break
at the positions where the code was broken in the input
file:
if (mask
&& ((mask[0] == ´\0´)
|| (mask[1] == ´\0´ &&
((mask[0] == ´0´) || (mask[0] == ´*´)))))
The idea behind this option is that lines which are too
long, but are already broken up, will not be touched by
GNU indent. Really messy code should be run through
indent at least once using the `--ignore-newlines´ option
though.
DISABLING FORMATTING
Formatting of C code may be disabled for portions of a
program by embedding special control comments in the pro
gram. To turn off formatting for a section of a program,
place the disabling control comment /* *INDENT-OFF* */ on
a line by itself just before that section. Program text
scanned after this control comment is output precisely as
input with no modifications until the corresponding
enabling comment is scanned on a line by itself. The dis
abling control comment is /* *INDENT-ON* */, and any text
following the comment on the line is also output unformat
ted. Formatting begins again with the input line follow
ing the enabling control comment.
More precisely, indent does not attempt to verify the
closing delimiter (*/) for these C comments, and any
whitespace on the line is totally transparent.
These control comments also function in their C++ formats,
namely // *INDENT-OFF* and // *INDENT-ON*.
It should be noted that the internal state of indent
remains unchanged over the course of the unformatted sec
tion. Thus, for example, turning off formatting in the
middle of a function and continuing it after the end of
the function may lead to bizarre results. It is therefore
wise to be somewhat modular in selecting code to be left
unformatted.
As a historical note, some earlier versions of indent pro
duced error messages beginning with *INDENT**. These ver
sions of indent were written to ignore any input text
lines which began with such error messages. I have
removed this incestuous feature from GNU indent.
MISCELLANEOUS OPTIONS
To find out what version of indent you have, use the com
mand indent -version. This will report the version number
of indent, without doing any of the normal processing.
The `-v´ option can be used to turn on verbose mode. When
in verbose mode, indent reports when it splits one line of
input into two more more lines of output, and gives some
size statistics at completion.
The `-pmt´ option causes indent to preserve the access and
modification times on the output files. Using this option
has the advantage that running indent on all source and
header files in a project won´t cause make to rebuild all
targets. This option is only available on Operating
Systems that have the POSIX utime(2) function.
BUGS
When indent is run twice on a file, with the same profile,
it should never change that file the second time. With
the current design of indent, this can not be guaranteed,
however, and it has not been extensively tested.
indent does not understand C. In some cases this leads to
the inability to join lines. The result is that running a
file through indent is irreversible, even if the used
input file was the result of running indent with a given
profile (`.indent.pro´).
While an attempt was made to get indent working for C++,
is will not do a good job on any C++ source except the
very simple.
indent does not look at the given `--line-length´ option
when writing comments to the output file. This results
often in comments being put far to the right. In order to
prohibit indent from joining a broken line that has a com
ment at the end, make sure that the comments start on the
first line of the break.
indent does not count lines and comments (see the `-v´
option) when indent is turned off with /* *INDENT-OFF* */.
Comments of the form /*UPPERCASE*/ are not treated as com
ment but as an identifier, causing them to be joined with
the next line. This renders comments of this type useless,
unless they are embedded in the code to begin with.
COPYRIGHT
The following copyright notice applies to the indent pro
gram. The copyright and copying permissions for this man
ual appear near the beginning of `indent.texinfo´ and
`indent.info´, and near the end of `indent.1´.
Copyright (c) 1999 Carlo Wood.
Copyright (c) 1995, 1996 Joseph Arceneaux.
Copyright (c) 1989, 1992, 1993, 1994, 1995, 1996 Free Software Foundation
Copyright (c) 1985 Sun Microsystems, Inc.
Copyright (c) 1980 The Regents of the University of California.
Copyright (c) 1976 Board of Trustees of the University of Illinois.
All rights reserved.
Redistribution and use in source and binary forms are permitted
provided that the above copyright notice and this paragraph are
duplicated in all such forms and that any documentation,
advertising materials, and other materials related to such
distribution and use acknowledge that the software was developed
by the University of California, Berkeley, the University of Illinois,
Urbana, and Sun Microsystems, Inc. The name of either University
or Sun Microsystems may not be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED ``AS IS´´ AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
PURPOSE.
Options´ Cross Key
Here is a list of options alphabetized by long option, to
help you find the corresponding short option.
--blank-lines-after-commas -bc
--blank-lines-after-declarations -bad
--blank-lines-after-procedures -bap
--blank-lines-before-block-comments -bbb
--braces-after-if-line -bl
--brace-indent -bli
--braces-after-struct-decl-line -bls
--braces-on-if-line -br
--braces-on-struct-decl-line -brs
--break-after-boolean-operator -nbbo
--break-before-boolean-operator -bbo
--break-function-decl-args -bfda
--case-indentation -clin
--case-brace-indentation -cbin
--comment-delimiters-on-blank-lines -cdb
--comment-indentation -cn
--continuation-indentation -cin
--continue-at-parentheses -lp
--cuddle-do-while -cdw
--cuddle-else -ce
--declaration-comment-column -cdn
--declaration-indentation -din
--dont-break-function-decl-args -nbfda
--dont-break-procedure-type -npsl
--dont-cuddle-do-while -ncdw
--dont-cuddle-else -nce
--dont-format-comments -nfca
--dont-format-first-column-comments -nfc1
--dont-line-up-parentheses -nlp
--dont-space-special-semicolon -nss
--dont-star-comments -nsc
--else-endif-column -cpn
--format-all-comments -fca
--format-first-column-comments -fc1
--gnu-style -gnu
--honour-newlines -hnl
--ignore-newlines -nhnl
--ignore-profile -npro
--indent-level -in
--k-and-r-style -kr
--leave-optional-blank-lines -nsob
--leave-preprocessor-space -lps
--line-comments-indentation -dn
--line-length -ln
--no-blank-lines-after-commas -nbc
--no-blank-lines-after-declarations -nbad
--no-blank-lines-after-procedures -nbap
--no-blank-lines-before-block-comments -nbbb
--no-comment-delimiters-on-blank-lines -ncdb
--no-space-after-casts -ncs
--no-parameter-indentation -nip
--no-space-after-for -nsaf
--no-space-after-function-call-names -npcs
--no-space-after-if -nsai
--no-space-after-parentheses -nprs
--no-space-after-while -nsaw
--no-tabs -nut
--no-verbosity -nv
--original -orig
--parameter-indentation -ipn
--paren-indentation -pin
--preserve-mtime -pmt
--procnames-start-lines -psl
--space-after-cast -cs
--space-after-for -saf
--space-after-if -sai
--space-after-parentheses -prs
--space-after-procedure-calls -pcs
--space-after-while -saw
--space-special-semicolon -ss
--standard-output -st
--start-left-side-of-comments -sc
--struct-brace-indentation -sbin
--swallow-optional-blank-lines -sob
--tab-size -tsn
--use-tabs -ut
--verbose -v
RETURN VALUE
Unknown
FILES
$HOME/.indent.pro holds default options for indent.
AUTHORS
Carlo Wood
Joseph Arceneaux
Jim Kingdon
HISTORY
Derived from the UCB program "indent".
COPYING
Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996 Free
Software Foundation, Inc. Copyright (C) 1995, 1996 Joseph
Arceneaux. Copyright (C) 1999 Carlo Wood.
Permission is granted to make and distribute verbatim
copies of this manual provided the copyright notice and
this permission notice are preserved on all copies.
INDENT(1L)