style revision 1.24
1/* $NetBSD: style,v 1.24 2003/03/10 03:50:38 lukem Exp $ */ 2 3/* 4 * The revision control tag appears first, with a blank line after it. 5 * Copyright text appears after the revision control tag. 6 */ 7 8/* 9 * The NetBSD source code style guide. 10 * (Previously known as KNF - Kernel Normal Form). 11 * 12 * from: @(#)style 1.12 (Berkeley) 3/18/94 13 */ 14/* 15 * An indent(1) profile approximating the style outlined in 16 * this document lives in /usr/share/misc/indent.pro. It is a 17 * useful tool to assist in converting code to KNF, but indent(1) 18 * output generated using this profile must not be considered to 19 * be an authoritative reference. 20 */ 21 22/* 23 * Source code revision control identifiers appear after any copyright 24 * text. Use the appropriate macros from <sys/cdefs.h>. Usually only one 25 * source file per program contains a __COPYRIGHT() section. 26 * Historic Berkeley code may also have an __SCCSID() section. 27 * Only one instance of each of these macros can occur in each file. 28 */ 29#include <sys/cdefs.h> 30__COPYRIGHT("@(#) Copyright (c) 2000\n\ 31 The NetBSD Foundation, inc. All rights reserved.\n"); 32__RCSID("$NetBSD: style,v 1.24 2003/03/10 03:50:38 lukem Exp $"); 33 34/* 35 * VERY important single-line comments look like this. 36 */ 37 38/* Most single-line comments look like this. */ 39 40/* 41 * Multi-line comments look like this. Make them real sentences. Fill 42 * them so they look like real paragraphs. 43 */ 44 45/* 46 * Attempt to wrap lines longer than 80 characters appropriately. 47 * Refer to the examples below for more information. 48 */ 49 50/* 51 * EXAMPLE HEADER FILE: 52 * 53 * A header file should protect itself against multiple inclusion. 54 * E.g, <sys/socket.h> would contain something like: 55 */ 56#ifndef _SYS_SOCKET_H_ 57#define _SYS_SOCKET_H_ 58/* 59 * Contents of #include file go between the #ifndef and the #endif at the end. 60 */ 61#endif /* !_SYS_SOCKET_H_ */ 62/* 63 * END OF EXAMPLE HEADER FILE. 64 */ 65 66/* 67 * Kernel include files come first. 68 */ 69#include <sys/types.h> /* Non-local includes in brackets. */ 70 71/* 72 * If it's a network program, put the network include files next. 73 * Group the includes files by subdirectory. 74 */ 75#include <net/if.h> 76#include <net/if_dl.h> 77#include <net/route.h> 78#include <netinet/in.h> 79#include <protocols/rwhod.h> 80 81/* 82 * Then there's a blank line, followed by the /usr include files. 83 * The /usr include files should be sorted! 84 */ 85#include <assert.h> 86#include <stdio.h> 87#include <stdlib.h> 88 89/* 90 * Global pathnames are defined in /usr/include/paths.h. Pathnames local 91 * to the program go in pathnames.h in the local directory. 92 */ 93#include <paths.h> 94 95/* Then, there's a blank line, and the user include files. */ 96#include "pathnames.h" /* Local includes in double quotes. */ 97 98/* 99 * ANSI function declarations for private functions (i.e. functions not used 100 * elsewhere) and the main() function go at the top of the source module. 101 * Don't associate a name with the types. I.e. use: 102 * void function(int); 103 * Use your discretion on indenting between the return type and the name, and 104 * how to wrap a prototype too long for a single line. In the latter case, 105 * lining up under the initial left parenthesis may be more readable. 106 * In any case, consistency is important! 107 */ 108static char *function(int, int, float, int); 109static int dirinfo(const char *, struct stat *, struct dirent *, 110 struct statfs *, int *, char **[]); 111static void usage(void); 112int main(int, char *[]); 113 114/* 115 * Macros are capitalized, parenthesized, and should avoid side-effects. 116 * Spacing before and after the macro name may be any whitespace, though 117 * use of TABs should be consistent through a file. 118 * If they are an inline expansion of a function, the function is defined 119 * all in lowercase, the macro has the same name all in uppercase. 120 * If the macro is an expression, wrap the expression in parenthesis. 121 * If the macro is more than a single statement, use ``do { ... } while (0)'', 122 * so that a trailing semicolon works. Right-justify the backslashes; it 123 * makes it easier to read. The CONSTCOND comment is to satisfy lint(1). 124 */ 125#define MACRO(v, w, x, y) \ 126do { \ 127 v = (x) + (y); \ 128 w = (y) + 2; \ 129} while (/* CONSTCOND */ 0) 130 131#define DOUBLE(x) ((x) * 2) 132 133/* Enum types are capitalized. No comma on the last element. */ 134enum enumtype { 135 ONE, 136 TWO 137} et; 138 139/* 140 * When declaring variables in structures, declare them organized by use in 141 * a manner to attempt to minimize memory wastage because of compiler alignment 142 * issues, then by size, and then by alphabetical order. E.g, don't use 143 * ``int a; char *b; int c; char *d''; use ``int a; int b; char *c; char *d''. 144 * Each variable gets its own type and line, although an exception can be made 145 * when declaring bitfields (to clarify that it's part of the one bitfield). 146 * Note that the use of bitfields in general is discouraged. 147 * 148 * Major structures should be declared at the top of the file in which they 149 * are used, or in separate header files, if they are used in multiple 150 * source files. Use of the structures should be by separate declarations 151 * and should be "extern" if they are declared in a header file. 152 * 153 * It may be useful to use a meaningful prefix for each member name. 154 * E.g, for ``struct softc'' the prefix could be ``sc_''. 155 */ 156struct foo { 157 struct foo *next; /* List of active foo */ 158 struct mumble amumble; /* Comment for mumble */ 159 int bar; 160 unsigned int baz:1, /* Bitfield; line up entries if desired */ 161 fuz:5, 162 zap:2; 163 u_int8_t flag; 164}; 165struct foo *foohead; /* Head of global foo list */ 166 167/* Make the structure name match the typedef. */ 168typedef struct BAR { 169 int level; 170} BAR; 171 172/* 173 * All major routines should have a comment briefly describing what 174 * they do. The comment before the "main" routine should describe 175 * what the program does. 176 */ 177int 178main(int argc, char *argv[]) 179{ 180 long num; 181 int ch; 182 char *ep; 183 184 /* 185 * At the start of main(), call setprogname() to set the program 186 * name. This does nothing on NetBSD, but increases portability 187 * to other systems. 188 */ 189 setprogname(argv[0]); 190 191 /* 192 * For consistency, getopt should be used to parse options. Options 193 * should be sorted in the getopt call and the switch statement, unless 194 * parts of the switch cascade. Elements in a switch statement that 195 * cascade should have a FALLTHROUGH comment. Numerical arguments 196 * should be checked for accuracy. Code that cannot be reached should 197 * have a NOTREACHED comment. 198 */ 199 while ((ch = getopt(argc, argv, "abn")) != -1) { 200 switch (ch) { /* Indent the switch. */ 201 case 'a': /* Don't indent the case. */ 202 aflag = 1; 203 /* FALLTHROUGH */ 204 case 'b': 205 bflag = 1; 206 break; 207 case 'n': 208 num = strtol(optarg, &ep, 10); 209 if (num <= 0 || *ep != '\0') 210 errx(1, "illegal number -- %s", optarg); 211 break; 212 case '?': 213 default: 214 usage(); 215 /* NOTREACHED */ 216 } 217 } 218 argc -= optind; 219 argv += optind; 220 221 /* 222 * Space after keywords (while, for, return, switch). No braces are 223 * used for control statements with zero or only a single statement, 224 * unless it's a long statement. 225 * 226 * Forever loops are done with for's, not while's. 227 */ 228 for (p = buf; *p != '\0'; ++p) 229 continue; /* Explicit no-op */ 230 for (;;) 231 stmt; 232 233 /* 234 * Parts of a for loop may be left empty. Don't put declarations 235 * inside blocks unless the routine is unusually complicated. 236 */ 237 for (; cnt < 15; cnt++) { 238 stmt1; 239 stmt2; 240 } 241 242 /* Second level indents are four spaces. */ 243 while (cnt < 20) 244 z = a + really + long + statement + that + needs + two lines + 245 gets + indented + four + spaces + on + the + second + 246 and + subsequent + lines; 247 248 /* 249 * Closing and opening braces go on the same line as the else. 250 * Don't add braces that aren't necessary except in cases where 251 * there are ambiguity or readability issues. 252 */ 253 if (test) { 254 /* 255 * I have a long comment here. 256 */ 257#ifdef zorro 258 z = 1; 259#else 260 b = 3; 261#endif 262 } else if (bar) { 263 stmt; 264 stmt; 265 } else 266 stmt; 267 268 /* No spaces after function names. */ 269 if ((result = function(a1, a2, a3, a4)) == NULL) 270 exit(1); 271 272 /* 273 * Unary operators don't require spaces, binary operators do. 274 * Don't excessively use parenthesis, but they should be used if 275 * statement is really confusing without them, such as: 276 * a = b->c[0] + ~d == (e || f) || g && h ? i : j >> 1; 277 */ 278 a = ((b->c[0] + ~d == (e || f)) || (g && h)) ? i : (j >> 1); 279 k = !(l & FLAGS); 280 281 /* 282 * Exits should be 0 on success, and 1 on failure. Don't denote 283 * all the possible exit points, using the integers 1 through 300. 284 * Avoid obvious comments such as "Exit 0 on success." 285 */ 286 exit(0); 287} 288 289/* 290 * The function type must be declared on a line by itself 291 * preceding the function. 292 */ 293static char * 294function(int a1, int a2, float fl, int a4) 295{ 296 /* 297 * When declaring variables in functions declare them sorted by size, 298 * then in alphabetical order; multiple ones per line are okay. 299 * Function prototypes should go in the include file "extern.h". 300 * If a line overflows reuse the type keyword. 301 * 302 * DO NOT initialize variables in the declarations. 303 */ 304 extern u_char one; 305 extern char two; 306 struct foo three, *four; 307 double five; 308 int *six, seven; 309 char *eight, *nine, ten, eleven, twelve, thirteen; 310 char fourteen, fifteen, sixteen; 311 312 /* 313 * Casts and sizeof's are not followed by a space. NULL is any 314 * pointer type, and doesn't need to be cast, so use NULL instead 315 * of (struct foo *)0 or (struct foo *)NULL. Also, test pointers 316 * against NULL. I.e. use: 317 * 318 * (p = f()) == NULL 319 * not: 320 * !(p = f()) 321 * 322 * Don't use `!' for tests unless it's a boolean. 323 * E.g. use "if (*p == '\0')", not "if (!*p)". 324 * 325 * Routines returning void * should not have their return values cast 326 * to any pointer type. 327 * 328 * Use err/warn(3), don't roll your own! 329 */ 330 if ((four = malloc(sizeof(struct foo))) == NULL) 331 err(1, NULL); 332 if ((six = (int *)overflow()) == NULL) 333 errx(1, "Number overflowed."); 334 335 /* No parentheses are needed around the return value. */ 336 return eight; 337} 338 339/* 340 * Use ANSI function declarations. ANSI function braces look like 341 * old-style (K&R) function braces. 342 * As per the wrapped prototypes, use your discretion on how to format 343 * the subsequent lines. 344 */ 345static int 346dirinfo(const char *p, struct stat *sb, struct dirent *de, struct statfs *sf, 347 int *rargc, char **rargv[]) 348{ /* Insert an empty line if the function has no local variables. */ 349 350 /* 351 * In system libraries, catch obviously invalid function arguments 352 * using _DIAGASSERT(3). 353 */ 354 _DIAGASSERT(p != NULL); 355 _DIAGASSERT(filedesc != -1); 356 357 if (stat(p, sb) < 0) 358 err(1, "Unable to stat %s", p); 359 360 /* 361 * To printf 64 bit quantities, use %ll and cast to (long long). 362 */ 363 printf("The size of %s is %lld\n", p, (long long)sb->st_size); 364} 365 366/* 367 * Functions that support variable numbers of arguments should look like this. 368 * (With the #include <stdarg.h> appearing at the top of the file with the 369 * other include files). 370 */ 371#include <stdarg.h> 372 373void 374vaf(const char *fmt, ...) 375{ 376 va_list ap; 377 378 va_start(ap, fmt); 379 STUFF; 380 va_end(ap); 381 /* No return needed for void functions. */ 382} 383 384static void 385usage(void) 386{ 387 388 /* 389 * Use printf(3), not fputs/puts/putchar/whatever, it's faster and 390 * usually cleaner, not to mention avoiding stupid bugs. 391 * Use snprintf(3) or strlcpy(3)/strlcat(3) instead of sprintf(3); 392 * again to avoid stupid bugs. 393 * 394 * Usage statements should look like the manual pages. Options w/o 395 * operands come first, in alphabetical order inside a single set of 396 * braces. Followed by options with operands, in alphabetical order, 397 * each in braces. Followed by required arguments in the order they 398 * are specified, followed by optional arguments in the order they 399 * are specified. A bar (`|') separates either/or options/arguments, 400 * and multiple options/arguments which are specified together are 401 * placed in a single set of braces. 402 * 403 * Use getprogname() instead of hardcoding the program name. 404 * 405 * "usage: f [-ade] [-b b_arg] [-m m_arg] req1 req2 [opt1 [opt2]]\n" 406 * "usage: f [-a | -b] [-c [-de] [-n number]]\n" 407 */ 408 (void)fprintf(stderr, "usage: %s [-ab]\n", getprogname()); 409 exit(1); 410} 411