/* $NetBSD: style,v 1.7 1998/02/09 06:58:39 enami Exp $ */
/*
* Style guide for the 4BSD KNF (Kernel Normal Form).
*
* from: @(#)style 1.12 (Berkeley) 3/18/94
*/
/*
* VERY important single-line comments look like this.
*/
/* Most single-line comments look like this. */
/*
* Multi-line comments look like this. Make them real sentences. Fill
* them so they look like real paragraphs.
*/
/*
* Kernel include files come first; normally, you'll need <sys/types.h>
* OR <sys/param.h>, but not both! <sys/types.h> includes <sys/cdefs.h>,
* and it's okay to depend on that.
*/
#include <sys/types.h> /* Non-local includes in brackets. */
/* If it's a network program, put the network include files next. */
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <protocols/rwhod.h>
/*
* Then there's a blank line, followed by the /usr include files.
* The /usr include files should be sorted!
*/
#include <stdio.h>
/*
* Global pathnames are defined in /usr/include/paths.h. Pathnames local
* to the program go in pathnames.h in the local directory.
*/
#include <paths.h>
/* Then, there's a blank line, and the user include files. */
#include "pathnames.h" /* Local includes in double quotes. */
/*
* ANSI function declarations for private functions (i.e. functions not used
* elsewhere) go at the top of the source module. Use the __P macro from
* the include file <sys/cdefs.h>. Only the kernel has a name associated with
* the types, i.e. in the kernel use:
*
* void function __P((int a));
*
* in user land use:
*
* void function __P((int));
*/
static char *function __P((int, const char *));
static void usage __P((void));
/*
* Macros are capitalized, parenthesized, and should avoid side-effects.
* If they are an inline expansion of a function, the function is defined
* all in lowercase, the macro has the same name all in uppercase. If the
* macro needs more than a single line, use braces. Right-justify the
* backslashes, it makes it easier to read.
*/
#define MACRO(x, y) { \
variable = (x) + (y); \
(y) += 2; \
}
/* Enum types are capitalized. */
enum enumtype { ONE, TWO } et;
/*
* When declaring variables in structures, declare them sorted by use, then
* by size, and then by alphabetical order. The first category normally
* doesn't apply, but there are exceptions. Each one gets its own line.
* Put a tab after the first word, i.e. use "int^Ix;" and "struct^Ifoo *x;".
*
* Major structures should be declared at the top of the file in which they
* are used, or in separate header files, if they are used in multiple
* source files. Use of the structures should be by separate declarations
* and should be "extern" if they are declared in a header file.
*/
struct foo {
struct foo *next; /* List of active foo */
struct mumble amumble; /* Comment for mumble */
int bar;
};
struct foo *foohead; /* Head of global foo list */
/* Make the structure name match the typedef. */
typedef struct _bar {
int level;
} BAR;
/*
* All major routines should have a comment briefly describing what
* they do. The comment before the "main" routine should describe
* what the program does.
*/
int
main(argc, argv)
int argc;
char *argv[];
{
extern char *optarg;
extern int optind;
long num;
int ch;
char *ep;
/*
* For consistency, getopt should be used to parse options. Options
* should be sorted in the getopt call and the switch statement, unless
* parts of the switch cascade. Elements in a switch statement that
* cascade should have a FALLTHROUGH comment. Numerical arguments
* should be checked for accuracy. Code that cannot be reached should
* have a NOTREACHED comment.
*/
while ((ch = getopt(argc, argv, "abn")) != -1)
switch (ch) { /* Indent the switch. */
case 'a': /* Don't indent the case. */
aflag = 1;
/* FALLTHROUGH */
case 'b':
bflag = 1;
break;
case 'n':
num = strtol(optarg, &ep, 10);
if (num <= 0 || *ep != '\0')
err("illegal number -- %s", optarg);
break;
case '?':
default:
usage();
/* NOTREACHED */
}
argc -= optind;
argv += optind;
/*
* Space after keywords (while, for, return, switch). No braces are
* used for control statements with zero or only a single statement.
*
* Forever loops are done with for's, not while's.
*/
for (p = buf; *p != '\0'; ++p);
for (;;)
stmt;
/*
* Parts of a for loop may be left empty. Don't put declarations
* inside blocks unless the routine is unusually complicated.
*/
for (; cnt < 15; cnt++) {
stmt1;
stmt2;
}
/* Second level indents are four spaces. */
while (cnt < 20)
z = a + really + long + statment + that + needs + two lines +
gets + indented + four + spaces + on + the + second +
and + subsequent + lines;
/*
* Closing and opening braces go on the same line as the else.
* Don't add braces that aren't necessary.
*/
if (test)
stmt;
else if (bar) {
stmt;
stmt;
} else
stmt;
/* No spaces after function names. */
if (error = function(a1, a2))
exit(error);
/*
* Unary operators don't require spaces, binary operators do. Don't
* use parenthesis unless they're required for precedence, or the
* statement is really confusing without them.
*/
a = b->c[0] + ~d == (e || f) || g && h ? i : j >> 1;
k = !(l & FLAGS);
/*
* Exits should be 0 on success, and 1 on failure. Don't denote
* all the possible exit points, using the integers 1 through 300.
*/
exit(0); /* Avoid obvious comments such as "Exit 0 on success." */
}
/*
* If a function type is declared, it should be on a line
* by itself preceeding the function.
*/
static char *
function(a1, a2, fl, a4)
int a1, a2, a4; /* Declare ints, too, don't default them. */
float fl; /* List in order declared, as much as possible. */
{
/*
* When declaring variables in functions declare them sorted by size,
* then in alphabetical order; multiple ones per line are okay. Old
* style function declarations can go on the same line. ANSI style
* function declarations should go in the include file "extern.h".
* If a line overflows reuse the type keyword.
*
* DO NOT initialize variables in the declarations.
*/
extern u_char one;
extern char two;
struct foo three, *four;
double five;
int *six, seven, eight();
char *nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen;
char *overflow __P((void));
void *mymalloc __P((u_int));
/*
* Casts and sizeof's are not followed by a space. NULL is any
* pointer type, and doesn't need to be cast, so use NULL instead
* of (struct foo *)0 or (struct foo *)NULL. Also, test pointers
* against NULL, i.e. use:
*
* (p = f()) == NULL
* not:
* !(p = f())
*
* Don't use '!' for tests unless it's a boolean, e.g. use
* "if (*p == '\0')", not "if (!*p)".
*
* Routines returning void * should not have their return values cast
* to any pointer type.
*
* Use err/warn(3), don't roll your own!
*/
if ((four = malloc(sizeof(struct foo))) == NULL)
err(1, NULL);
if ((six = (int *)overflow()) == NULL)
errx(1, "Number overflowed.");
return (eight);
}
/*
* Don't use ANSI function declarations unless you absolutely have to,
* i.e. you're declaring functions with variable numbers of arguments.
*
* ANSI function braces look like regular function braces.
*/
function(int a1, int a2)
{
...
}
/* Variable numbers of arguments should look like this. */
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
void
#if __STDC__
vaf(const char *fmt, ...)
#else
vaf(fmt, va_alist)
char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
STUFF;
va_end(ap); /* No return needed for void functions. */
}
static void
usage()
{ /* Insert an empty line if the function has no local variables. */
/*
* Use printf(3), not fputs/puts/putchar/whatever, it's faster and
* usually cleaner, not to mention avoiding stupid bugs.
*
* Usage statements should look like the manual pages. Options w/o
* operands come first, in alphabetical order inside a single set of
* braces. Followed by options with operands, in alphabetical order,
* each in braces. Followed by required arguments in the order they
* are specified, followed by optional arguments in the order they
* are specified. A bar ('|') separates either/or options/arguments,
* and multiple options/arguments which are specified together are
* placed in a single set of braces.
*
* "usage: f [-ade] [-b b_arg] [-m m_arg] req1 req2 [opt1 [opt2]]\n"
* "usage: f [-a | -b] [-c [-de] [-n number]]\n"
*/
(void)fprintf(stderr, "usage: f [-ab]\n");
exit(1);
}