Name

indent − indent and format C program source

Syntax

indent input [output] [flags]

Description

The indent command is intended primarily as a C program formatter. Specifically, indent indents code lines, aligns comments, inserts spaces around operators where necessary and breaks up declaration lists as in “int a,b,c;”.

The indent command does not break up long statements to make them fit within the maximum line length, but it does flag lines that are too long.  Lines are broken so that each statement starts a new line, and braces appear alone on a line. Also, an attempt is made to line up identifiers in declarations.

The flags that can be specified follow. They can appear before or after the file names.  If the output file is omitted, the formatted file is written back into input and a “backup” copy of input is written in the current directory.  If input is named “/blah/blah/file”, the backup file is named “.Bfile”.  If output is specified, indent checks to make sure it is different from input.

Options

The following options are used to control the formatting style imposed by indent:

−lnnnDetermines maximum length of output line.  The default is 75. 

−cnnnDetermines column in which comments start.  The default is 33. 

−cdnnnDetermines column in which comments on declarations start.  The default is for these comments to start in the same column as other comments. 

−innnDetermines number of spaces for one indentation level.  The default is 4. 

−dj,−ndjCauses declarations to be left justified.  −ndj causes them to be indented the same as code.  The default is −ndj. 

−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 it gives some size statistics at completion. The default is −nv. 

−bc,−nbcForces newline after each comma in a declaration.  −nbc turns off this option.  The default is −bc. 

−dnnnControls the placement of comments which are not to the right of code.  Specifying −d2 means that such comments are placed two indentation levels to the left of code.  The default −d0 lines up these comments with the code.  See the section on comment indentation below. 

−br,−blSpecifying −bl causes complex statements to be lined up in a space order.  For example,

   if (...)
   {
       code
   }

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

   if (...) {
       code
   }

You may set up your own “profile” of defaults to indent by creating the file “.indent.pro” in your login directory and including whatever switches you like. 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 profile file must be a single line of not more than 127 characters. The switches should be separated on the line by spaces or tabs.

Multiline expressions

The indent command does not break up complicated expressions that extend over multiple lines.  However, it usually indents such expressions that have already been broken up correctly. Such an expression might look like the following:

x =
        (
            (Arbitrary parenthesized expression)
            +
            (
                (Parenthesized expression)
                *
                (Parenthesized expression)
            )
        );
 

Comments

The indent command recognizes the following four kinds of comments:

1) straight text

2) “box” comments

3) UNIX-style comments

4) comments that should be passed through unchanged

The comments are interpreted as follows:

“Box” comments The indent command assumes that any comment with a dash immediately after the start of comment (i.e. “/*−”) is a comment surrounded by a box of stars.  Each line of such a comment is left unchanged, except that the first non-blank character of each successive line is lined up with the beginning slash of the first line.  Box comments are indented (see below).

“Unix-style” comments This is the type of section header which is used extensively in the UNIX system source.  If the start of comment (“/*”) appears on a line by itself, indent assumes that it is a UNIX-style comment.  These are treated similarly to box comments, except the first non-blank character on each line is lined up with the ‘*’ of the “/*”.

Unchanged comments Any comment which starts in column 1 is left completely unchanged.  This is intended primarily for documentation header pages.  The check for unchanged comments is made before the check for UNIX-style comments. 

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

Comment indentation

Box, UNIX-style, and straight text comments may be indented.  If a comment is on a line with code it is started in the “comment column”, which is set by the −cnnn command line parameter.  Otherwise, the comment is started at nnn indentation levels less than where code is currently being placed, where nnn is specified by the −dnnn command line parameter.  (Indented comments is never be placed in column 1.)  If the code on a line extends past the comment column, the comment is moved to the next line. 

Restrictions

Does not know how to format “long” declarations. 

Diagnostics

Diagnostic error messages, mostly to tell that a text line has been broken or is too long for the output line. 

Files

.indent.proprofile file