xref: /freebsd/sys/contrib/openzfs/man/man1/cstyle.1 (revision 5956d97f4b3204318ceb6aa9c77bd0bc6ea87a41)
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23.Dd May 26, 2021
24.Dt CSTYLE 1
25.Os
26.
27.Sh NAME
28.Nm cstyle
29.Nd check for some common stylistic errors in C source files
30.Sh SYNOPSIS
31.Nm
32.Op Fl chpvCP
33.Oo Ar file Oc Ns …
34.Sh DESCRIPTION
35.Nm
36inspects C source files (*.c and *.h) for common stylistic errors.
37It attempts to check for the cstyle documented in
38.Lk http://www.cis.upenn.edu/~lee/06cse480/data/cstyle.ms.pdf .
39Note that there is much in that document that
40.Em cannot
41be checked for; just because your code is
42.Nm Ns -clean
43does not mean that you've followed Sun's C style.
44.Em Caveat emptor .
45.
46.Sh OPTIONS
47.Bl -tag -width "-c"
48.It Fl c
49Check continuation line indentation inside of functions.
50Sun's C style
51states that all statements must be indented to an appropriate tab stop,
52and any continuation lines after them must be indented
53.Em exactly
54four spaces from the start line.
55This option enables a series of checks designed to find
56continuation line problems within functions only.
57The checks have some limitations; see
58.Sy CONTINUATION CHECKING ,
59below.
60.It Fl p
61Performs some of the more picky checks.
62Includes ANSI
63.Sy #else
64and
65.Sy #endif
66rules, and tries to detect spaces after casts.
67Used as part of the putback checks.
68.It Fl v
69Verbose output; includes the text of the line of error, and, for
70.Fl c ,
71the first statement in the current continuation block.
72.It Fl P
73Check for use of non-POSIX types.
74Historically, types like
75.Sy u_int
76and
77.Sy u_long
78were used, but they are now deprecated in favor of the POSIX
79types
80.Sy uint_t ,
81.Sy ulong_t ,
82etc.
83This detects any use of the deprecated types.
84Used as part of the putback checks.
85.It Fl g
86Also print GitHub-Actions-style
87.Li ::error
88output.
89.El
90.
91.Sh ENVIRONMENT
92.Bl -tag -compact -width ".Ev CI"
93.It Ev CI
94If set and nonempty, equivalent to
95.Fl g .
96.El
97.
98.Sh CONTINUATION CHECKING
99The continuation checker is a reasonably simple state machine that knows
100something about how C is laid out, and can match parenthesis, etc. over
101multiple lines.
102It does have some limitations:
103.Bl -enum
104.It
105Preprocessor macros which cause unmatched parenthesis will confuse the
106checker for that line.
107To fix this, you'll need to make sure that each branch of the
108.Sy #if
109statement has balanced parenthesis.
110.It
111Some
112.Xr cpp 1
113macros do not require
114.Sy ;\& Ns s after them.
115Any such macros
116.Em must
117be ALL_CAPS; any lower case letters will cause bad output.
118.Pp
119The bad output will generally be corrected after the next
120.Sy ;\& , { , No or Sy } .
121.El
122Some continuation error messages deserve some additional explanation:
123.Bl -tag -width Ds
124.It Sy multiple statements continued over multiple lines
125A multi-line statement which is not broken at statement boundaries.
126For example:
127.Bd -literal -compact -offset Ds
128if (this_is_a_long_variable == another_variable) a =
129    b + c;
130.Ed
131.Pp
132Will trigger this error.
133Instead, do:
134.Bd -literal -compact -offset Ds
135if (this_is_a_long_variable == another_variable)
136    a = b + c;
137.Ed
138.It Sy empty if/for/while body not on its own line
139For visibility, empty bodies for if, for, and while statements should be
140on their own line.
141For example:
142.Bd -literal -compact -offset Ds
143while (do_something(&x) == 0);
144.Ed
145.Pp
146Will trigger this error.
147Instead, do:
148.Bd -literal -compact -offset Ds
149while (do_something(&x) == 0)
150    ;
151.Ed
152.El
153