INDENT(1L) INDENT(1L)
NAME
indent - changes the appearance of a C program by inserting
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 Version
, 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 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.
INDENT(1L) INDENT(1L)
-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 column
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.
INDENT(1L) INDENT(1L)
-cpn, --else-endif-columnn
Put comments to the right of #else and #endif statements
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
Break the line before all arguments in a declaration.
See DECLARATIONS.
-bfde, --break-function-decl-args
Break the line after the last argument in a declaration.
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 definitions
by n spaces.
See INDENTATION.
INDENT(1L) INDENT(1L)
-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 opera-
tors.
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.
INDENT(1L) INDENT(1L)
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.
INDENT(1L) INDENT(1L)
-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 certain
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.
INDENT(1L) INDENT(1L)
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
INDENT(1L) INDENT(1L)
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 spec-
ify 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
INDENT(1L) INDENT(1L)
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 look for a profile the environment variable
INDENT_PROFILE. If that exists its value is expected to name
the file that is to be used. If the environment variable
does not exist, indent looks for `.indent.pro' in the cur-
rent directory
and use that if found. Finally 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 ver-
sions of indent, which load both files if
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 specified
options always override background options (See
COMMON STYLES). You can prevent indent from reading an
`.indent.pro' file by specifying the `-npro' option.
BACKUP FILES
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 suffix
to the original file name. The default for this suffix 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
INDENT(1L) INDENT(1L)
suffix by setting the environment variable
SIMPLE_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 particu-
lar 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 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 backups
will be made. If its value is `numbered-existing', then
numbered backups will be made if there already exist num-
bered backups for the file being indented; otherwise, a sim-
ple 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 back-
ground option, which specifies a set of values for all other
options. However, explicitly specified options always over-
ride 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
INDENT(1L) INDENT(1L)
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 seman-
tic 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 corre-
sponds 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 follow-
ing 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 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
The `-bap' option forces a blank line after every procedure
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.
INDENT(1L) INDENT(1L)
--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 procedure
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");
}
INDENT(1L) INDENT(1L)
/* 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++ `/*', terminated with `*/' and
may contain newline characters. C++ comments begin with the
delimiter `//' and end at the newline.
indent handles comments differently depending upon indent
attempts to distinguish between comments statements, com-
ments which follow declarations, comments following prepro-
cessor 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 proce-
dures and aggregates, and those found within them. In par-
ticular, 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 comment beginning in the
leftmost column; such a comment is output at that column.
indent attempts to leave boxed comments 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 pre-
cisely, 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 column as the star of the
opening delimiter.
INDENT(1L) INDENT(1L)
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 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 beginning 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 comment.
The margin is not respected if the comment is not being for-
matted.
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 col-
umn). This alignment may be affected by the `-d' option,
which specifies an amount by which such comments are moved
to the left, or unindented. For example, `-d2' places com-
ments two spaces to the left of code. By default, comments
are aligned with code, unless they begin in the first col-
umn, 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
INDENT(1L) INDENT(1L)
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 following
preprocessor directives #else and #endif.
If the code to the left of the comment exceeds the beginning
column, the comment column will be extended to the next tab-
stop column past the end of the code, or in the case of pre-
processor directives, to one space past the end of the
directive. This extension lasts only for the output 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 comments
with the `-sc' option. Thus, the single-line comment 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 fol-
lowing:
INDENT(1L) INDENT(1L)
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 preceding
`}'. For example, with `-br -ce' you get the following:
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:
{
INDENT(1L) INDENT(1L)
++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 state-
ment, the `-ss' option will cause a space to be placed
before the semicolon. This emphasizes the semicolon, 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 example,
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
INDENT(1L) INDENT(1L)
known as the `Bill_Shannon' option.
The `-saf' option forces a space between an for and the fol-
lowing parenthesis. This is the default.
The `-sai' option forces a space between an if and the fol-
lowing 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 vari-
ables 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
INDENT(1L) INDENT(1L)
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 one indention level deeper than
the function declaration. This is particularly helpful for
functions with long argument lists. The option `-bfde'
causes a newline to be forced before the closing bracket of
the function declaration. For both options the 'n' setting
is the default: -nbdfa and -nbdfe.
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);
With, in addition, the `-bfde' 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 pro-
cedure. 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 speci-
fied 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
INDENT(1L) INDENT(1L)
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 beginning
of a statement such as if or for is encountered, the inden-
tation level is increased by the value specified by the `-i'
option. For example, use `-i8' to specify an eight charac-
ter indentation for each level. When a statement 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:
INDENT(1L) INDENT(1L)
if ((((i < 2 &&
k > 0) || p == 0) &&
q == 1) ||
n = 0)
indent assumes that tabs are placed input and output charac-
ter streams. These intervals 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 defini-
tions 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 com-
mand lines between the character `#' and the command name.
By default, indent removes this space, but specifying
directs indent to leave this space unmodified. The option
`-ppi' overrides `-nlps' and `-lps'.
This option can be used to request that preprocessor condi-
tional statements can be indented by to given number of
spaces, for example with the option `-ppi 3'
#if X
#if Y
#define Z 1
#else
#define Z 0
#endif
#endif
becomes
#if X
# if Y
# define Z 1
# else
# define Z 0
# endif
INDENT(1L) INDENT(1L)
#endif
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 intelligent or
flexible yet.
Currently there are two options that allows one to interfere
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' &&
INDENT(1L) INDENT(1L)
((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 pro-
gram by embedding special control comments in the program.
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 disabling control comment
is /* *INDENT-ON* */, and any text following the comment on
the line is also output unformatted. Formatting begins
again with the input line following the enabling control
comment.
More precisely, indent does not attempt to verify the clos-
ing 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 section. Thus,
for example, turning off formatting in the middle of a func-
tion and continuing it after the end of the function may
lead to bizarre results. It is therefore wise to be some-
what 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 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 command
indent -version. This will report the indent, without doing
any of the
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.
INDENT(1L) INDENT(1L)
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
Please report any bugs to bug-indent@gnu.org.
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, and it
has not been extensively tested.
indent does not understand C. In 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++, it
will not do a good job on any C++ source except the very
simplest.
indent does not look at the 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 comment at the end, make sure that
the comments start on the first line of the break.
indent does not count lines and 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 manual
appear near the beginning of `indent.texinfo' and
`indent.info', and near the end of `indent.1'.
Copyright (c) 2001 David Ingamells.
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.
INDENT(1L) INDENT(1L)
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
--break-function-decl-args-end -bfde
--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-function-decl-args-end -nbfde
--dont-break-procedure-type -npsl
--dont-cuddle-do-while -ncdw
--dont-cuddle-else -nce
--dont-format-comments -nfca
INDENT(1L) INDENT(1L)
--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
INDENT(1L) INDENT(1L)
RETURN VALUE
Unknown
FILES
$HOME/.indent.pro holds default options for indent.
AUTHORS
Carlo Wood
Joseph Arceneaux
Jim Kingdon
David Ingamells
HISTORY
Derived from the UCB program "indent".
COPYING
Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996 Free Soft-
ware Foundation, Inc. Copyright (C) 1995, 1996 Joseph Arce-
neaux. Copyright (C) 1999 Carlo Wood. Copyright (C) 2001
David Ingamells.
Permission is granted to make and distribute verbatim copies
of this manual provided the copyright notice and this per-
mission notice are preserved on all copies.