1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)queue.h 8.5 (Berkeley) 8/20/94 34 * $FreeBSD: src/sys/sys/queue.h,v 1.32.2.7 2002/04/17 14:21:02 des Exp $ 35 * $DragonFly: src/sys/sys/queue.h,v 1.2 2003/06/17 04:28:58 dillon Exp $ 36 */ 37 38 #ifndef _SYS_QUEUE_H_ 39 #define _SYS_QUEUE_H_ 40 41 #include <machine/ansi.h> /* for __offsetof */ 42 43 /* 44 * This file defines five types of data structures: singly-linked lists, 45 * singly-linked tail queues, lists, tail queues, and circular queues. 46 * 47 * A singly-linked list is headed by a single forward pointer. The elements 48 * are singly linked for minimum space and pointer manipulation overhead at 49 * the expense of O(n) removal for arbitrary elements. New elements can be 50 * added to the list after an existing element or at the head of the list. 51 * Elements being removed from the head of the list should use the explicit 52 * macro for this purpose for optimum efficiency. A singly-linked list may 53 * only be traversed in the forward direction. Singly-linked lists are ideal 54 * for applications with large datasets and few or no removals or for 55 * implementing a LIFO queue. 56 * 57 * A singly-linked tail queue is headed by a pair of pointers, one to the 58 * head of the list and the other to the tail of the list. The elements are 59 * singly linked for minimum space and pointer manipulation overhead at the 60 * expense of O(n) removal for arbitrary elements. New elements can be added 61 * to the list after an existing element, at the head of the list, or at the 62 * end of the list. Elements being removed from the head of the tail queue 63 * should use the explicit macro for this purpose for optimum efficiency. 64 * A singly-linked tail queue may only be traversed in the forward direction. 65 * Singly-linked tail queues are ideal for applications with large datasets 66 * and few or no removals or for implementing a FIFO queue. 67 * 68 * A list is headed by a single forward pointer (or an array of forward 69 * pointers for a hash table header). The elements are doubly linked 70 * so that an arbitrary element can be removed without a need to 71 * traverse the list. New elements can be added to the list before 72 * or after an existing element or at the head of the list. A list 73 * may only be traversed in the forward direction. 74 * 75 * A tail queue is headed by a pair of pointers, one to the head of the 76 * list and the other to the tail of the list. The elements are doubly 77 * linked so that an arbitrary element can be removed without a need to 78 * traverse the list. New elements can be added to the list before or 79 * after an existing element, at the head of the list, or at the end of 80 * the list. A tail queue may be traversed in either direction. 81 * 82 * A circle queue is headed by a pair of pointers, one to the head of the 83 * list and the other to the tail of the list. The elements are doubly 84 * linked so that an arbitrary element can be removed without a need to 85 * traverse the list. New elements can be added to the list before or after 86 * an existing element, at the head of the list, or at the end of the list. 87 * A circle queue may be traversed in either direction, but has a more 88 * complex end of list detection. 89 * 90 * For details on the use of these macros, see the queue(3) manual page. 91 * 92 * 93 * SLIST LIST STAILQ TAILQ CIRCLEQ 94 * _HEAD + + + + + 95 * _HEAD_INITIALIZER + + + + + 96 * _ENTRY + + + + + 97 * _INIT + + + + + 98 * _EMPTY + + + + + 99 * _FIRST + + + + + 100 * _NEXT + + + + + 101 * _PREV - - - + + 102 * _LAST - - + + + 103 * _FOREACH + + + + + 104 * _FOREACH_REVERSE - - - + + 105 * _INSERT_HEAD + + + + + 106 * _INSERT_BEFORE - + - + + 107 * _INSERT_AFTER + + + + + 108 * _INSERT_TAIL - - + + + 109 * _REMOVE_HEAD + - + - - 110 * _REMOVE + + + + + 111 * 112 */ 113 114 /* 115 * Singly-linked List declarations. 116 */ 117 #define SLIST_HEAD(name, type) \ 118 struct name { \ 119 struct type *slh_first; /* first element */ \ 120 } 121 122 #define SLIST_HEAD_INITIALIZER(head) \ 123 { NULL } 124 125 #define SLIST_ENTRY(type) \ 126 struct { \ 127 struct type *sle_next; /* next element */ \ 128 } 129 130 /* 131 * Singly-linked List functions. 132 */ 133 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 134 135 #define SLIST_FIRST(head) ((head)->slh_first) 136 137 #define SLIST_FOREACH(var, head, field) \ 138 for ((var) = SLIST_FIRST((head)); \ 139 (var); \ 140 (var) = SLIST_NEXT((var), field)) 141 142 #define SLIST_INIT(head) do { \ 143 SLIST_FIRST((head)) = NULL; \ 144 } while (0) 145 146 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 147 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 148 SLIST_NEXT((slistelm), field) = (elm); \ 149 } while (0) 150 151 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 152 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 153 SLIST_FIRST((head)) = (elm); \ 154 } while (0) 155 156 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 157 158 #define SLIST_REMOVE(head, elm, type, field) do { \ 159 if (SLIST_FIRST((head)) == (elm)) { \ 160 SLIST_REMOVE_HEAD((head), field); \ 161 } \ 162 else { \ 163 struct type *curelm = SLIST_FIRST((head)); \ 164 while (SLIST_NEXT(curelm, field) != (elm)) \ 165 curelm = SLIST_NEXT(curelm, field); \ 166 SLIST_NEXT(curelm, field) = \ 167 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ 168 } \ 169 } while (0) 170 171 #define SLIST_REMOVE_HEAD(head, field) do { \ 172 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 173 } while (0) 174 175 /* 176 * Singly-linked Tail queue declarations. 177 */ 178 #define STAILQ_HEAD(name, type) \ 179 struct name { \ 180 struct type *stqh_first;/* first element */ \ 181 struct type **stqh_last;/* addr of last next element */ \ 182 } 183 184 #define STAILQ_HEAD_INITIALIZER(head) \ 185 { NULL, &(head).stqh_first } 186 187 #define STAILQ_ENTRY(type) \ 188 struct { \ 189 struct type *stqe_next; /* next element */ \ 190 } 191 192 /* 193 * Singly-linked Tail queue functions. 194 */ 195 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 196 197 #define STAILQ_FIRST(head) ((head)->stqh_first) 198 199 #define STAILQ_FOREACH(var, head, field) \ 200 for((var) = STAILQ_FIRST((head)); \ 201 (var); \ 202 (var) = STAILQ_NEXT((var), field)) 203 204 #define STAILQ_INIT(head) do { \ 205 STAILQ_FIRST((head)) = NULL; \ 206 (head)->stqh_last = &STAILQ_FIRST((head)); \ 207 } while (0) 208 209 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 210 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 211 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 212 STAILQ_NEXT((tqelm), field) = (elm); \ 213 } while (0) 214 215 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 216 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 217 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 218 STAILQ_FIRST((head)) = (elm); \ 219 } while (0) 220 221 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 222 STAILQ_NEXT((elm), field) = NULL; \ 223 *(head)->stqh_last = (elm); \ 224 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 225 } while (0) 226 227 #define STAILQ_LAST(head, type, field) \ 228 (STAILQ_EMPTY(head) ? \ 229 NULL : \ 230 ((struct type *) \ 231 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 232 233 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 234 235 #define STAILQ_REMOVE(head, elm, type, field) do { \ 236 if (STAILQ_FIRST((head)) == (elm)) { \ 237 STAILQ_REMOVE_HEAD(head, field); \ 238 } \ 239 else { \ 240 struct type *curelm = STAILQ_FIRST((head)); \ 241 while (STAILQ_NEXT(curelm, field) != (elm)) \ 242 curelm = STAILQ_NEXT(curelm, field); \ 243 if ((STAILQ_NEXT(curelm, field) = \ 244 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ 245 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ 246 } \ 247 } while (0) 248 249 #define STAILQ_REMOVE_HEAD(head, field) do { \ 250 if ((STAILQ_FIRST((head)) = \ 251 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 252 (head)->stqh_last = &STAILQ_FIRST((head)); \ 253 } while (0) 254 255 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 256 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ 257 (head)->stqh_last = &STAILQ_FIRST((head)); \ 258 } while (0) 259 260 /* 261 * List declarations. 262 */ 263 #define LIST_HEAD(name, type) \ 264 struct name { \ 265 struct type *lh_first; /* first element */ \ 266 } 267 268 #define LIST_HEAD_INITIALIZER(head) \ 269 { NULL } 270 271 #define LIST_ENTRY(type) \ 272 struct { \ 273 struct type *le_next; /* next element */ \ 274 struct type **le_prev; /* address of previous next element */ \ 275 } 276 277 /* 278 * List functions. 279 */ 280 281 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 282 283 #define LIST_FIRST(head) ((head)->lh_first) 284 285 #define LIST_FOREACH(var, head, field) \ 286 for ((var) = LIST_FIRST((head)); \ 287 (var); \ 288 (var) = LIST_NEXT((var), field)) 289 290 #define LIST_INIT(head) do { \ 291 LIST_FIRST((head)) = NULL; \ 292 } while (0) 293 294 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 295 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 296 LIST_NEXT((listelm), field)->field.le_prev = \ 297 &LIST_NEXT((elm), field); \ 298 LIST_NEXT((listelm), field) = (elm); \ 299 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 300 } while (0) 301 302 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 303 (elm)->field.le_prev = (listelm)->field.le_prev; \ 304 LIST_NEXT((elm), field) = (listelm); \ 305 *(listelm)->field.le_prev = (elm); \ 306 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 307 } while (0) 308 309 #define LIST_INSERT_HEAD(head, elm, field) do { \ 310 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 311 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 312 LIST_FIRST((head)) = (elm); \ 313 (elm)->field.le_prev = &LIST_FIRST((head)); \ 314 } while (0) 315 316 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 317 318 #define LIST_REMOVE(elm, field) do { \ 319 if (LIST_NEXT((elm), field) != NULL) \ 320 LIST_NEXT((elm), field)->field.le_prev = \ 321 (elm)->field.le_prev; \ 322 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 323 } while (0) 324 325 /* 326 * Tail queue declarations. 327 */ 328 #define TAILQ_HEAD(name, type) \ 329 struct name { \ 330 struct type *tqh_first; /* first element */ \ 331 struct type **tqh_last; /* addr of last next element */ \ 332 } 333 334 #define TAILQ_HEAD_INITIALIZER(head) \ 335 { NULL, &(head).tqh_first } 336 337 #define TAILQ_ENTRY(type) \ 338 struct { \ 339 struct type *tqe_next; /* next element */ \ 340 struct type **tqe_prev; /* address of previous next element */ \ 341 } 342 343 /* 344 * Tail queue functions. 345 */ 346 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 347 348 #define TAILQ_FIRST(head) ((head)->tqh_first) 349 350 #define TAILQ_FOREACH(var, head, field) \ 351 for ((var) = TAILQ_FIRST((head)); \ 352 (var); \ 353 (var) = TAILQ_NEXT((var), field)) 354 355 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 356 for ((var) = TAILQ_LAST((head), headname); \ 357 (var); \ 358 (var) = TAILQ_PREV((var), headname, field)) 359 360 #define TAILQ_INIT(head) do { \ 361 TAILQ_FIRST((head)) = NULL; \ 362 (head)->tqh_last = &TAILQ_FIRST((head)); \ 363 } while (0) 364 365 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 366 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 367 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 368 &TAILQ_NEXT((elm), field); \ 369 else \ 370 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 371 TAILQ_NEXT((listelm), field) = (elm); \ 372 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 373 } while (0) 374 375 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 376 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 377 TAILQ_NEXT((elm), field) = (listelm); \ 378 *(listelm)->field.tqe_prev = (elm); \ 379 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 380 } while (0) 381 382 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 383 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 384 TAILQ_FIRST((head))->field.tqe_prev = \ 385 &TAILQ_NEXT((elm), field); \ 386 else \ 387 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 388 TAILQ_FIRST((head)) = (elm); \ 389 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 390 } while (0) 391 392 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 393 TAILQ_NEXT((elm), field) = NULL; \ 394 (elm)->field.tqe_prev = (head)->tqh_last; \ 395 *(head)->tqh_last = (elm); \ 396 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 397 } while (0) 398 399 #define TAILQ_LAST(head, headname) \ 400 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 401 402 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 403 404 #define TAILQ_PREV(elm, headname, field) \ 405 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 406 407 #define TAILQ_REMOVE(head, elm, field) do { \ 408 if ((TAILQ_NEXT((elm), field)) != NULL) \ 409 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 410 (elm)->field.tqe_prev; \ 411 else \ 412 (head)->tqh_last = (elm)->field.tqe_prev; \ 413 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 414 } while (0) 415 416 /* 417 * Circular queue declarations. 418 */ 419 #define CIRCLEQ_HEAD(name, type) \ 420 struct name { \ 421 struct type *cqh_first; /* first element */ \ 422 struct type *cqh_last; /* last element */ \ 423 } 424 425 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 426 { (void *)&(head), (void *)&(head) } 427 428 #define CIRCLEQ_ENTRY(type) \ 429 struct { \ 430 struct type *cqe_next; /* next element */ \ 431 struct type *cqe_prev; /* previous element */ \ 432 } 433 434 /* 435 * Circular queue functions. 436 */ 437 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 438 439 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 440 441 #define CIRCLEQ_FOREACH(var, head, field) \ 442 for ((var) = CIRCLEQ_FIRST((head)); \ 443 (var) != (void *)(head) || ((var) = NULL); \ 444 (var) = CIRCLEQ_NEXT((var), field)) 445 446 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 447 for ((var) = CIRCLEQ_LAST((head)); \ 448 (var) != (void *)(head) || ((var) = NULL); \ 449 (var) = CIRCLEQ_PREV((var), field)) 450 451 #define CIRCLEQ_INIT(head) do { \ 452 CIRCLEQ_FIRST((head)) = (void *)(head); \ 453 CIRCLEQ_LAST((head)) = (void *)(head); \ 454 } while (0) 455 456 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 457 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \ 458 CIRCLEQ_PREV((elm), field) = (listelm); \ 459 if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \ 460 CIRCLEQ_LAST((head)) = (elm); \ 461 else \ 462 CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\ 463 CIRCLEQ_NEXT((listelm), field) = (elm); \ 464 } while (0) 465 466 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 467 CIRCLEQ_NEXT((elm), field) = (listelm); \ 468 CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \ 469 if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \ 470 CIRCLEQ_FIRST((head)) = (elm); \ 471 else \ 472 CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\ 473 CIRCLEQ_PREV((listelm), field) = (elm); \ 474 } while (0) 475 476 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 477 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \ 478 CIRCLEQ_PREV((elm), field) = (void *)(head); \ 479 if (CIRCLEQ_LAST((head)) == (void *)(head)) \ 480 CIRCLEQ_LAST((head)) = (elm); \ 481 else \ 482 CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \ 483 CIRCLEQ_FIRST((head)) = (elm); \ 484 } while (0) 485 486 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 487 CIRCLEQ_NEXT((elm), field) = (void *)(head); \ 488 CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \ 489 if (CIRCLEQ_FIRST((head)) == (void *)(head)) \ 490 CIRCLEQ_FIRST((head)) = (elm); \ 491 else \ 492 CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \ 493 CIRCLEQ_LAST((head)) = (elm); \ 494 } while (0) 495 496 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 497 498 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 499 500 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 501 502 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 503 if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \ 504 CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \ 505 else \ 506 CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \ 507 CIRCLEQ_PREV((elm), field); \ 508 if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \ 509 CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \ 510 else \ 511 CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \ 512 CIRCLEQ_NEXT((elm), field); \ 513 } while (0) 514 515 #ifdef _KERNEL 516 517 /* 518 * XXX insque() and remque() are an old way of handling certain queues. 519 * They bogusly assumes that all queue heads look alike. 520 */ 521 522 struct quehead { 523 struct quehead *qh_link; 524 struct quehead *qh_rlink; 525 }; 526 527 #ifdef __GNUC__ 528 529 static __inline void 530 insque(void *a, void *b) 531 { 532 struct quehead *element = (struct quehead *)a, 533 *head = (struct quehead *)b; 534 535 element->qh_link = head->qh_link; 536 element->qh_rlink = head; 537 head->qh_link = element; 538 element->qh_link->qh_rlink = element; 539 } 540 541 static __inline void 542 remque(void *a) 543 { 544 struct quehead *element = (struct quehead *)a; 545 546 element->qh_link->qh_rlink = element->qh_rlink; 547 element->qh_rlink->qh_link = element->qh_link; 548 element->qh_rlink = 0; 549 } 550 551 #else /* !__GNUC__ */ 552 553 void insque __P((void *a, void *b)); 554 void remque __P((void *a)); 555 556 #endif /* __GNUC__ */ 557 558 #endif /* _KERNEL */ 559 560 #endif /* !_SYS_QUEUE_H_ */ 561