1 /*
2  * Not used definitions from this file were removed.
3  *
doSomethingInProtocol:(float)4  * @(#)$Id: queue.h,v 1.1 2010/09/30 18:05:08 simon Exp $
5  */
6 
7 /*-
8  * Copyright (c) 1991, 1993
9  *	The Regents of the University of California.  All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
36  * $FreeBSD: src/sys/sys/queue.h,v 1.58.2.1 2005/01/31 23:26:57 imp Exp $
37  */
38 
39 #ifndef _SYS_QUEUE_H_
40 #define	_SYS_QUEUE_H_
41 
42 #include <stddef.h>	/* For offsetof(), as defined in SUSv3. */
43 
44 /*
45  * This file defines four types of data structures: singly-linked lists,
46  * singly-linked tail queues, lists and tail queues.
47  *
48  * A singly-linked list is headed by a single forward pointer. The elements
49  * are singly linked for minimum space and pointer manipulation overhead at
50  * the expense of O(n) removal for arbitrary elements. New elements can be
51  * added to the list after an existing element or at the head of the list.
52  * Elements being removed from the head of the list should use the explicit
53  * macro for this purpose for optimum efficiency. A singly-linked list may
54  * only be traversed in the forward direction.  Singly-linked lists are ideal
55  * for applications with large datasets and few or no removals or for
56  * implementing a LIFO queue.
57  *
58  * A singly-linked tail queue is headed by a pair of pointers, one to the
59  * head of the list and the other to the tail of the list. The elements are
60  * singly linked for minimum space and pointer manipulation overhead at the
61  * expense of O(n) removal for arbitrary elements. New elements can be added
62  * to the list after an existing element, at the head of the list, or at the
63  * end of the list. Elements being removed from the head of the tail queue
64  * should use the explicit macro for this purpose for optimum efficiency.
65  * A singly-linked tail queue may only be traversed in the forward direction.
66  * Singly-linked tail queues are ideal for applications with large datasets
67  * and few or no removals or for implementing a FIFO queue.
68  *
69  * A list is headed by a single forward pointer (or an array of forward
70  * pointers for a hash table header). The elements are doubly linked
71  * so that an arbitrary element can be removed without a need to
72  * traverse the list. New elements can be added to the list before
73  * or after an existing element or at the head of the list. A list
74  * may only be traversed in the forward direction.
75  *
76  * A tail queue is headed by a pair of pointers, one to the head of the
77  * list and the other to the tail of the list. The elements are doubly
78  * linked so that an arbitrary element can be removed without a need to
79  * traverse the list. New elements can be added to the list before or
80  * after an existing element, at the head of the list, or at the end of
81  * the list. A tail queue may be traversed in either direction.
82  *
83  * For details on the use of these macros, see the queue(3) manual page.
84  *
85  *
86  *				SLIST	LIST	STAILQ	TAILQ
87  * _HEAD			+	+	+	+
88  * _HEAD_INITIALIZER		+	+	+	+
89  * _ENTRY			+	+	+	+
90  * _INIT			+	+	+	+
91  * _EMPTY			+	+	+	+
92  * _FIRST			+	+	+	+
93  * _NEXT			+	+	+	+
94  * _PREV			-	-	-	+
95  * _LAST			-	-	+	+
96  * _FOREACH			+	+	+	+
97  * _FOREACH_SAFE		+	+	+	+
98  * _FOREACH_REVERSE		-	-	-	+
99  * _FOREACH_REVERSE_SAFE	-	-	-	+
100  * _INSERT_HEAD			+	+	+	+
101  * _INSERT_BEFORE		-	+	-	+
102  * _INSERT_AFTER		+	+	+	+
103  * _INSERT_TAIL			-	-	+	+
104  * _CONCAT			-	-	+	+
105  * _REMOVE_HEAD			+	-	+	-
106  * _REMOVE			+	+	+	+
107  *
108  */
109 #define	QUEUE_MACRO_DEBUG 0
110 #if QUEUE_MACRO_DEBUG
111 /* Store the last 2 places the queue element or head was altered */
112 struct qm_trace {
113 	char * lastfile;
114 	int lastline;
115 	char * prevfile;
116 	int prevline;
117 };
118 
119 #define	TRACEBUF	struct qm_trace trace;
120 #define	TRASHIT(x)	do {(x) = (void *)-1;} while (/* CONSTCOND */ 0)
121 
122 #define	QMD_TRACE_HEAD(head) do {					\
123 	(head)->trace.prevline = (head)->trace.lastline;		\
124 	(head)->trace.prevfile = (head)->trace.lastfile;		\
125 	(head)->trace.lastline = __LINE__;				\
126 	(head)->trace.lastfile = __FILE__;				\
127 } while (/* CONSTCOND */ 0)
128 
129 #define	QMD_TRACE_ELEM(elem) do {					\
130 	(elem)->trace.prevline = (elem)->trace.lastline;		\
131 	(elem)->trace.prevfile = (elem)->trace.lastfile;		\
132 	(elem)->trace.lastline = __LINE__;				\
133 	(elem)->trace.lastfile = __FILE__;				\
134 } while (/* CONSTCOND */ 0)
135 
136 #else
137 #define	QMD_TRACE_ELEM(elem)
138 #define	QMD_TRACE_HEAD(head)
139 #define	TRACEBUF
140 #define	TRASHIT(x)
141 #endif	/* QUEUE_MACRO_DEBUG */
142 
143 /*
144  * Singly-linked List declarations.
145  */
146 #define	SLIST_HEAD(name, type)						\
147 struct name {								\
148 	struct type *slh_first;	/* first element */			\
149 }
150 
151 #define	SLIST_HEAD_INITIALIZER(head)					\
152 	{ NULL }
153 
154 #define	SLIST_ENTRY(type)						\
155 struct {								\
156 	struct type *sle_next;	/* next element */			\
157 }
158 
159 /*
160  * Singly-linked List functions.
161  */
162 #define	SLIST_EMPTY(head)	((head)->slh_first == NULL)
163 
164 #define	SLIST_FIRST(head)	((head)->slh_first)
165 
166 #define	SLIST_FOREACH(var, head, field)					\
167 	for ((var) = SLIST_FIRST((head));				\
168 	    (var);							\
169 	    (var) = SLIST_NEXT((var), field))
170 
171 #define	SLIST_FOREACH_SAFE(var, head, field, tvar)			\
172 	for ((var) = SLIST_FIRST((head));				\
173 	    (var) && ((tvar) = SLIST_NEXT((var), field), 1);		\
174 	    (var) = (tvar))
175 
176 #define	SLIST_FOREACH_PREVPTR(var, varp, head, field)			\
177 	for ((varp) = &SLIST_FIRST((head));				\
178 	    ((var) = *(varp)) != NULL;					\
179 	    (varp) = &SLIST_NEXT((var), field))
180 
181 #define	SLIST_INIT(head) do {						\
182 	SLIST_FIRST((head)) = NULL;					\
183 } while (/* CONSTCOND */ 0)
184 
185 #define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
186 	SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);	\
187 	SLIST_NEXT((slistelm), field) = (elm);				\
188 } while (/* CONSTCOND */ 0)
189 
190 #define	SLIST_INSERT_HEAD(head, elm, field) do {			\
191 	SLIST_NEXT((elm), field) = SLIST_FIRST((head));			\
192 	SLIST_FIRST((head)) = (elm);					\
193 } while (/* CONSTCOND */ 0)
194 
195 #define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
196 
197 #define	SLIST_REMOVE(head, elm, type, field) do {			\
198 	if (SLIST_FIRST((head)) == (elm)) {				\
199 		SLIST_REMOVE_HEAD((head), field);			\
200 	}								\
201 	else {								\
202 		struct type *curelm = SLIST_FIRST((head));		\
203 		while (SLIST_NEXT(curelm, field) != (elm))		\
204 			curelm = SLIST_NEXT(curelm, field);		\
205 		SLIST_NEXT(curelm, field) =				\
206 		    SLIST_NEXT(SLIST_NEXT(curelm, field), field);	\
207 	}								\
208 } while (/* CONSTCOND */ 0)
209 
210 #define	SLIST_REMOVE_HEAD(head, field) do {				\
211 	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);	\
212 } while (/* CONSTCOND */ 0)
213 
214 /*
215  * Singly-linked Tail queue declarations.
216  */
217 #define	STAILQ_HEAD(name, type)						\
218 struct name {								\
219 	struct type *stqh_first;/* first element */			\
220 	struct type **stqh_last;/* addr of last next element */		\
221 }
222 
223 #define	STAILQ_HEAD_INITIALIZER(head)					\
224 	{ NULL, &(head).stqh_first }
225 
226 #define	STAILQ_ENTRY(type)						\
227 struct {								\
228 	struct type *stqe_next;	/* next element */			\
229 }
230 
231 /*
232  * Singly-linked Tail queue functions.
233  */
234 #define	STAILQ_CONCAT(head1, head2) do {				\
235 	if (!STAILQ_EMPTY((head2))) {					\
236 		*(head1)->stqh_last = (head2)->stqh_first;		\
237 		(head1)->stqh_last = (head2)->stqh_last;		\
238 		STAILQ_INIT((head2));					\
239 	}								\
240 } while (/* CONSTCOND */ 0)
241 
242 #define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)
243 
244 #define	STAILQ_FIRST(head)	((head)->stqh_first)
245 
246 #define	STAILQ_FOREACH(var, head, field)				\
247 	for((var) = STAILQ_FIRST((head));				\
248 	   (var);							\
249 	   (var) = STAILQ_NEXT((var), field))
250 
251 
252 #define	STAILQ_FOREACH_SAFE(var, head, field, tvar)			\
253 	for ((var) = STAILQ_FIRST((head));				\
254 	    (var) && ((tvar) = STAILQ_NEXT((var), field), 1);		\
255 	    (var) = (tvar))
256 
257 #define	STAILQ_INIT(head) do {						\
258 	STAILQ_FIRST((head)) = NULL;					\
259 	(head)->stqh_last = &STAILQ_FIRST((head));			\
260 } while (/* CONSTCOND */ 0)
261 
262 #define	STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {		\
263 	if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
264 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
265 	STAILQ_NEXT((tqelm), field) = (elm);				\
266 } while (/* CONSTCOND */ 0)
267 
268 #define	STAILQ_INSERT_HEAD(head, elm, field) do {			\
269 	if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL)	\
270 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
271 	STAILQ_FIRST((head)) = (elm);					\
272 } while (/* CONSTCOND */ 0)
273 
274 #define	STAILQ_INSERT_TAIL(head, elm, field) do {			\
275 	STAILQ_NEXT((elm), field) = NULL;				\
276 	*(head)->stqh_last = (elm);					\
277 	(head)->stqh_last = &STAILQ_NEXT((elm), field);			\
278 } while (/* CONSTCOND */ 0)
279 
280 #define	STAILQ_LAST(head, type, field)					\
281 	(STAILQ_EMPTY((head)) ?						\
282 		NULL :							\
283 	        ((struct type *)					\
284 		((char *)((head)->stqh_last) - offsetof(struct type, field))))
285 
286 #define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next)
287 
288 #define	STAILQ_REMOVE(head, elm, type, field) do {			\
289 	if (STAILQ_FIRST((head)) == (elm)) {				\
290 		STAILQ_REMOVE_HEAD((head), field);			\
291 	}								\
292 	else {								\
293 		struct type *curelm = STAILQ_FIRST((head));		\
294 		while (STAILQ_NEXT(curelm, field) != (elm))		\
295 			curelm = STAILQ_NEXT(curelm, field);		\
296 		if ((STAILQ_NEXT(curelm, field) =			\
297 		     STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
298 			(head)->stqh_last = &STAILQ_NEXT((curelm), field);\
299 	}								\
300 } while (/* CONSTCOND */ 0)
301 
302 #define	STAILQ_REMOVE_HEAD(head, field) do {				\
303 	if ((STAILQ_FIRST((head)) =					\
304 	     STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)		\
305 		(head)->stqh_last = &STAILQ_FIRST((head));		\
306 } while (/* CONSTCOND */ 0)
307 
308 #define	STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {			\
309 	if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL)	\
310 		(head)->stqh_last = &STAILQ_FIRST((head));		\
311 } while (/* CONSTCOND */ 0)
312 
313 /*
314  * List declarations.
315  */
316 #define	LIST_HEAD(name, type)						\
317 struct name {								\
318 	struct type *lh_first;	/* first element */			\
319 }
320 
321 #define	LIST_HEAD_INITIALIZER(head)					\
322 	{ NULL }
323 
324 #define	LIST_ENTRY(type)						\
325 struct {								\
326 	struct type *le_next;	/* next element */			\
327 	struct type **le_prev;	/* address of previous next element */	\
328 }
329 
330 /*
331  * List functions.
332  */
333 
334 #define	LIST_EMPTY(head)	((head)->lh_first == NULL)
335 
336 #define	LIST_FIRST(head)	((head)->lh_first)
337 
338 #define	LIST_FOREACH(var, head, field)					\
339 	for ((var) = LIST_FIRST((head));				\
340 	    (var);							\
341 	    (var) = LIST_NEXT((var), field))
342 
343 #define	LIST_FOREACH_SAFE(var, head, field, tvar)			\
344 	for ((var) = LIST_FIRST((head));				\
345 	    (var) && ((tvar) = LIST_NEXT((var), field), 1);		\
346 	    (var) = (tvar))
347 
348 #define	LIST_INIT(head) do {						\
349 	LIST_FIRST((head)) = NULL;					\
350 } while (/* CONSTCOND */ 0)
351 
352 #define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
353 	if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
354 		LIST_NEXT((listelm), field)->field.le_prev =		\
355 		    &LIST_NEXT((elm), field);				\
356 	LIST_NEXT((listelm), field) = (elm);				\
357 	(elm)->field.le_prev = &LIST_NEXT((listelm), field);		\
358 } while (/* CONSTCOND */ 0)
359 
360 #define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
361 	(elm)->field.le_prev = (listelm)->field.le_prev;		\
362 	LIST_NEXT((elm), field) = (listelm);				\
363 	*(listelm)->field.le_prev = (elm);				\
364 	(listelm)->field.le_prev = &LIST_NEXT((elm), field);		\
365 } while (/* CONSTCOND */ 0)
366 
367 #define	LIST_INSERT_HEAD(head, elm, field) do {				\
368 	if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)	\
369 		LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
370 	LIST_FIRST((head)) = (elm);					\
371 	(elm)->field.le_prev = &LIST_FIRST((head));			\
372 } while (/* CONSTCOND */ 0)
373 
374 #define	LIST_NEXT(elm, field)	((elm)->field.le_next)
375 
376 #define	LIST_REMOVE(elm, field) do {					\
377 	if (LIST_NEXT((elm), field) != NULL)				\
378 		LIST_NEXT((elm), field)->field.le_prev = 		\
379 		    (elm)->field.le_prev;				\
380 	*(elm)->field.le_prev = LIST_NEXT((elm), field);		\
381 } while (/* CONSTCOND */ 0)
382 
383 /*
384  * Tail queue declarations.
385  */
386 #define	TAILQ_HEAD(name, type)						\
387 struct name {								\
388 	struct type *tqh_first;	/* first element */			\
389 	struct type **tqh_last;	/* addr of last next element */		\
390 	TRACEBUF							\
391 }
392 
393 #define	TAILQ_HEAD_INITIALIZER(head)					\
394 	{ NULL, &(head).tqh_first }
395 
396 #define	TAILQ_ENTRY(type)						\
397 struct {								\
398 	struct type *tqe_next;	/* next element */			\
399 	struct type **tqe_prev;	/* address of previous next element */	\
400 	TRACEBUF							\
401 }
402 
403 /*
404  * Tail queue functions.
405  */
406 #define	TAILQ_CONCAT(head1, head2, field) do {				\
407 	if (!TAILQ_EMPTY(head2)) {					\
408 		*(head1)->tqh_last = (head2)->tqh_first;		\
409 		(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;	\
410 		(head1)->tqh_last = (head2)->tqh_last;			\
411 		TAILQ_INIT((head2));					\
412 		QMD_TRACE_HEAD(head);					\
413 		QMD_TRACE_HEAD(head2);					\
414 	}								\
415 } while (/* CONSTCOND */ 0)
416 
417 #define	TAILQ_EMPTY(head)	((head)->tqh_first == NULL)
418 
419 #define	TAILQ_FIRST(head)	((head)->tqh_first)
420 
421 #define	TAILQ_FOREACH(var, head, field)					\
422 	for ((var) = TAILQ_FIRST((head));				\
423 	    (var);							\
424 	    (var) = TAILQ_NEXT((var), field))
425 
426 #define	TAILQ_FOREACH_SAFE(var, head, field, tvar)			\
427 	for ((var) = TAILQ_FIRST((head));				\
428 	    (var) && ((tvar) = TAILQ_NEXT((var), field), 1);		\
429 	    (var) = (tvar))
430 
431 #define	TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
432 	for ((var) = TAILQ_LAST((head), headname);			\
433 	    (var);							\
434 	    (var) = TAILQ_PREV((var), headname, field))
435 
436 #define	TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)	\
437 	for ((var) = TAILQ_LAST((head), headname);			\
438 	    (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);	\
439 	    (var) = (tvar))
440 
441 #define	TAILQ_INIT(head) do {						\
442 	TAILQ_FIRST((head)) = NULL;					\
443 	(head)->tqh_last = &TAILQ_FIRST((head));			\
444 	QMD_TRACE_HEAD(head);						\
445 } while (/* CONSTCOND */ 0)
446 
447 #define	TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
448 	if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
449 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
450 		    &TAILQ_NEXT((elm), field);				\
451 	else {								\
452 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
453 		QMD_TRACE_HEAD(head);					\
454 	}								\
455 	TAILQ_NEXT((listelm), field) = (elm);				\
456 	(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);		\
457 	QMD_TRACE_ELEM(&(elm)->field);					\
458 	QMD_TRACE_ELEM(&listelm->field);				\
459 } while (/* CONSTCOND */ 0)
460 
461 #define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
462 	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
463 	TAILQ_NEXT((elm), field) = (listelm);				\
464 	*(listelm)->field.tqe_prev = (elm);				\
465 	(listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);		\
466 	QMD_TRACE_ELEM(&(elm)->field);					\
467 	QMD_TRACE_ELEM(&listelm->field);				\
468 } while (/* CONSTCOND */ 0)
469 
470 #define	TAILQ_INSERT_HEAD(head, elm, field) do {			\
471 	if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)	\
472 		TAILQ_FIRST((head))->field.tqe_prev =			\
473 		    &TAILQ_NEXT((elm), field);				\
474 	else								\
475 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
476 	TAILQ_FIRST((head)) = (elm);					\
477 	(elm)->field.tqe_prev = &TAILQ_FIRST((head));			\
478 	QMD_TRACE_HEAD(head);						\
479 	QMD_TRACE_ELEM(&(elm)->field);					\
480 } while (/* CONSTCOND */ 0)
481 
482 #define	TAILQ_INSERT_TAIL(head, elm, field) do {			\
483 	TAILQ_NEXT((elm), field) = NULL;				\
484 	(elm)->field.tqe_prev = (head)->tqh_last;			\
485 	*(head)->tqh_last = (elm);					\
486 	(head)->tqh_last = &TAILQ_NEXT((elm), field);			\
487 	QMD_TRACE_HEAD(head);						\
488 	QMD_TRACE_ELEM(&(elm)->field);					\
489 } while (/* CONSTCOND */ 0)
490 
491 #define	TAILQ_LAST(head, headname)					\
492 	(*(((struct headname *)((head)->tqh_last))->tqh_last))
493 
494 #define	TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
495 
496 #define	TAILQ_PREV(elm, headname, field)				\
497 	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
498 
499 #define	TAILQ_REMOVE(head, elm, field) do {				\
500 	if ((TAILQ_NEXT((elm), field)) != NULL)				\
501 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
502 		    (elm)->field.tqe_prev;				\
503 	else {								\
504 		(head)->tqh_last = (elm)->field.tqe_prev;		\
505 		QMD_TRACE_HEAD(head);					\
506 	}								\
507 	*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);		\
508 	TRASHIT((elm)->field.tqe_next);					\
509 	TRASHIT((elm)->field.tqe_prev);					\
510 	QMD_TRACE_ELEM(&(elm)->field);					\
511 } while (/* CONSTCOND */ 0)
512 
513 #endif /* !_SYS_QUEUE_H_ */
514