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.TH cstyle 1 "28 March 2005"
.SH NAME
.I cstyle
\- check for some common stylistic errors in C source files
.SH SYNOPSIS
\fBcstyle [-chpvCP] [-o constructs] [file...]\fP
.LP
.SH DESCRIPTION
.IX "OS-Net build tools" "cstyle" "" "\fBcstyle\fP"
.LP
.I cstyle
inspects C source files (*.c and *.h) for common stylistic errors.  It
attempts to check for the cstyle documented in
\fIhttp://www.cis.upenn.edu/~lee/06cse480/data/cstyle.ms.pdf\fP.
Note that there is much in that document that
.I cannot
be checked for; just because your code is \fBcstyle(1)\fP clean does not
mean that you've followed Sun's C style.  \fICaveat emptor\fP.
.LP
.SH OPTIONS
.LP
The following options are supported:
.TP 4
.B \-c
Check continuation line indentation inside of functions.  Sun's C style
states that all statements must be indented to an appropriate tab stop,
and any continuation lines after them must be indented \fIexactly\fP four
spaces from the start line.  This option enables a series of checks
designed to find continuation line problems within functions only.  The
checks have some limitations;  see CONTINUATION CHECKING, below.
.LP
.TP 4
.B \-h
Performs heuristic checks that are sometimes wrong.  Not generally used.
.LP
.TP 4
.B \-p
Performs some of the more picky checks.  Includes ANSI #else and #endif
rules, and tries to detect spaces after casts.  Used as part of the
putback checks.
.LP
.TP 4
.B \-v
Verbose output;  includes the text of the line of error, and, for
\fB-c\fP, the first statement in the current continuation block.
.LP
.TP 4
.B \-C
Ignore errors in header comments (i.e. block comments starting in the
first column).  Not generally used.
.LP
.TP 4
.B \-P
Check for use of non-POSIX types.  Historically, types like "u_int" and
"u_long" were used, but they are now deprecated in favor of the POSIX
types uint_t, ulong_t, etc.  This detects any use of the deprecated
types.  Used as part of the putback checks.
.LP
.TP 4
.B \-o \fIconstructs\fP
Allow a comma-separated list of additional constructs.  Available
constructs include:
.LP
.TP 10
.B doxygen
Allow doxygen-style block comments (\fB/**\fP and \fB/*!\fP)
.LP
.TP 10
.B splint
Allow splint-style lint comments (\fB/*@...@*/\fP)
.LP
.SH NOTES
.LP
The cstyle rule for the OS/Net consolidation is that all new files must
be \fB-pP\fP clean.  For existing files, the following invocations are
run against both the old and new files:
.LP
.TP 4
\fBcstyle file\fB
.LP
.TP 4
\fBcstyle -p file\fB
.LP
.TP 4
\fBcstyle -pP file\fB
.LP
If the old file gave no errors for one of the invocations, the new file
must also give no errors.  This way, files can only become more clean.
.LP
.SH CONTINUATION CHECKING
.LP
The continuation checker is a reasonably simple state machine that knows
something about how C is laid out, and can match parenthesis, etc. over
multiple lines.  It does have some limitations:
.LP
.TP 4
.B 1.
Preprocessor macros which cause unmatched parenthesis will confuse the
checker for that line.  To fix this, you'll need to make sure that each
branch of the #if statement has balanced parenthesis.
.LP
.TP 4
.B 2.
Some \fBcpp\fP macros do not require ;s after them.  Any such macros
*must* be ALL_CAPS; any lower case letters will cause bad output.
.LP
The bad output will generally be corrected after the next \fB;\fP,
\fB{\fP, or \fB}\fP.
.LP
Some continuation error messages deserve some additional explanation
.LP
.TP 4
.B
multiple statements continued over multiple lines
A multi-line statement which is not broken at statement
boundaries.  For example:
.RS 4
.HP 4
if (this_is_a_long_variable == another_variable) a =
.br
b + c;
.LP
Will trigger this error.  Instead, do:
.HP 8
if (this_is_a_long_variable == another_variable)
.br
a = b + c;
.RE
.LP
.TP 4
.B
empty if/for/while body not on its own line
For visibility, empty bodies for if, for, and while statements should be
on their own line.  For example:
.RS 4
.HP 4
while (do_something(&x) == 0);
.LP
Will trigger this error.  Instead, do:
.HP 8
while (do_something(&x) == 0)
.br
;
.RE