Build fixes for fnl/musl

third_party/libevent/linux/sys/queue.h

-/*      $OpenBSD: queue.h,v 1.16 2000/09/07 19:47:59 art Exp $  */
-/*      $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $       */
-
 /*
  * Copyright (c) 1991, 1993
  *      The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 15 matching lines @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  */
 
 #ifndef _SYS_QUEUE_H_
 #define _SYS_QUEUE_H_
 
 /*
- * This file defines five types of data structures: singly-linked lists, 
+ * This file defines five types of data structures: singly-linked lists,

[jamesr, 2015/10/21 22:55:43]

where'd this file come from?

[cdotstout, 2015/10/22 00:03:24]

removed it, I realized it's already there

  * lists, simple queues, tail queues, and circular queues.
  *
- *
- * A singly-linked list is headed by a single forward pointer. The elements
- * are singly linked for minimum space and pointer manipulation overhead at
- * the expense of O(n) removal for arbitrary elements. New elements can be
- * added to the list after an existing element or at the head of the list.
- * Elements being removed from the head of the list should use the explicit
- * macro for this purpose for optimum efficiency. A singly-linked list may
- * only be traversed in the forward direction.  Singly-linked lists are ideal
- * for applications with large datasets and few or no removals or for
- * implementing a LIFO queue.
+ * A singly-linked list is headed by a single forward pointer. The
+ * elements are singly linked for minimum space and pointer manipulation
+ * overhead at the expense of O(n) removal for arbitrary elements. New
+ * elements can be added to the list after an existing element or at the
+ * head of the list.  Elements being removed from the head of the list
+ * should use the explicit macro for this purpose for optimum
+ * efficiency. A singly-linked list may only be traversed in the forward
+ * direction.  Singly-linked lists are ideal for applications with large
+ * datasets and few or no removals or for implementing a LIFO queue.
  *
  * A list is headed by a single forward pointer (or an array of forward
  * pointers for a hash table header). The elements are doubly linked
  * so that an arbitrary element can be removed without a need to
  * traverse the list. New elements can be added to the list before
  * or after an existing element or at the head of the list. A list
  * may only be traversed in the forward direction.
  *
  * A simple queue is headed by a pair of pointers, one the head of the
  * list and the other to the tail of the list. The elements are singly
  * linked to save space, so elements can only be removed from the
- * head of the list. New elements can be added to the list before or after
+ * head of the list. New elements can be added to the list after
  * an existing element, at the head of the list, or at the end of the
  * list. A simple queue may only be traversed in the forward direction.
  *
  * A tail queue is headed by a pair of pointers, one to the head of the
  * list and the other to the tail of the list. The elements are doubly
  * linked so that an arbitrary element can be removed without a need to
  * traverse the list. New elements can be added to the list before or
  * after an existing element, at the head of the list, or at the end of
  * the list. A tail queue may be traversed in either direction.
  *
  * A circle queue is headed by a pair of pointers, one to the head of the
  * list and the other to the tail of the list. The elements are doubly
  * linked so that an arbitrary element can be removed without a need to
  * traverse the list. New elements can be added to the list before or after
  * an existing element, at the head of the list, or at the end of the list.
  * A circle queue may be traversed in either direction, but has a more
  * complex end of list detection.
  *
  * For details on the use of these macros, see the queue(3) manual page.
  */
 
 /*
- * Singly-linked List definitions.
- */
-#define SLIST_HEAD(name, type)                                          \
-struct name {                                                           \
-        struct type *slh_first; /* first element */                     \
-}
- 
-#define SLIST_HEAD_INITIALIZER(head)                                    \
+ * List definitions.
+ */
+#define LIST_HEAD(name, type)                                           \
+struct name {                                                           \
+        struct type *lh_first;  /* first element */                     \
+}
+
+#define LIST_HEAD_INITIALIZER(head)                                     \
         { NULL }
 
-#ifndef WIN32
-#define SLIST_ENTRY(type)                                               \
-struct {                                                                \
-        struct type *sle_next;  /* next element */                      \
-}
-#endif
-
-/*
- * Singly-linked List access methods.
- */
-#define SLIST_FIRST(head)       ((head)->slh_first)
-#define SLIST_END(head)         NULL
-#define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
-#define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
-
-#define SLIST_FOREACH(var, head, field)                                 \
-        for((var) = SLIST_FIRST(head);                                  \
-            (var) != SLIST_END(head);                                   \
-            (var) = SLIST_NEXT(var, field))
-
-/*
- * Singly-linked List functions.
- */
-#define SLIST_INIT(head) {                                              \
-        SLIST_FIRST(head) = SLIST_END(head);                            \
-}
-
-#define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
-        (elm)->field.sle_next = (slistelm)->field.sle_next;             \
-        (slistelm)->field.sle_next = (elm);                             \
-} while (0)
-
-#define SLIST_INSERT_HEAD(head, elm, field) do {                        \
-        (elm)->field.sle_next = (head)->slh_first;                      \
-        (head)->slh_first = (elm);                                      \
-} while (0)
-
-#define SLIST_REMOVE_HEAD(head, field) do {                             \
-        (head)->slh_first = (head)->slh_first->field.sle_next;          \
-} while (0)
-
-/*
- * List definitions.
- */
-#define LIST_HEAD(name, type)                                           \
-struct name {                                                           \
-        struct type *lh_first;  /* first element */                     \
-}
-
-#define LIST_HEAD_INITIALIZER(head)                                     \
-        { NULL }
-
-#define LIST_ENTRY(type)                                                \
+#define LIST_ENTRY(type)                                                \
 struct {                                                                \
         struct type *le_next;   /* next element */                      \
         struct type **le_prev;  /* address of previous next element */  \
 }
 
 /*
- * List access methods
- */
-#define LIST_FIRST(head)                ((head)->lh_first)
-#define LIST_END(head)                  NULL
-#define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
-#define LIST_NEXT(elm, field)           ((elm)->field.le_next)
-
-#define LIST_FOREACH(var, head, field)                                  \
-        for((var) = LIST_FIRST(head);                                   \
-            (var)!= LIST_END(head);                                     \
-            (var) = LIST_NEXT(var, field))
-
-/*
  * List functions.
  */
 #define LIST_INIT(head) do {                                            \
-        LIST_FIRST(head) = LIST_END(head);                              \
-} while (0)
-
-#define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
+        (head)->lh_first = NULL;                                        \
+} while (/*CONSTCOND*/0)
+
+#define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
                 (listelm)->field.le_next->field.le_prev =               \
                     &(elm)->field.le_next;                              \
         (listelm)->field.le_next = (elm);                               \
         (elm)->field.le_prev = &(listelm)->field.le_next;               \
-} while (0)
+} while (/*CONSTCOND*/0)
 
 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
         (elm)->field.le_prev = (listelm)->field.le_prev;                \
         (elm)->field.le_next = (listelm);                               \
         *(listelm)->field.le_prev = (elm);                              \
         (listelm)->field.le_prev = &(elm)->field.le_next;               \
-} while (0)
-
-#define LIST_INSERT_HEAD(head, elm, field) do {                         \
+} while (/*CONSTCOND*/0)
+
+#define LIST_INSERT_HEAD(head, elm, field) do {                         \
         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
         (head)->lh_first = (elm);                                       \
         (elm)->field.le_prev = &(head)->lh_first;                       \
-} while (0)
-
-#define LIST_REMOVE(elm, field) do {                                    \
+} while (/*CONSTCOND*/0)
+
+#define LIST_REMOVE(elm, field) do {                                    \
         if ((elm)->field.le_next != NULL)                               \
-                (elm)->field.le_next->field.le_prev =                   \
+                (elm)->field.le_next->field.le_prev =                   \
                     (elm)->field.le_prev;                               \
         *(elm)->field.le_prev = (elm)->field.le_next;                   \
-} while (0)
-
-#define LIST_REPLACE(elm, elm2, field) do {                             \
-        if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
-                (elm2)->field.le_next->field.le_prev =                  \
-                    &(elm2)->field.le_next;                             \
-        (elm2)->field.le_prev = (elm)->field.le_prev;                   \
-        *(elm2)->field.le_prev = (elm2);                                \
-} while (0)
+} while (/*CONSTCOND*/0)
+
+#define LIST_FOREACH(var, head, field)                                  \
+        for ((var) = ((head)->lh_first);                                \
+                (var);                                                  \
+                (var) = ((var)->field.le_next))
+
+/*
+ * List access methods.
+ */
+#define LIST_EMPTY(head)                ((head)->lh_first == NULL)
+#define LIST_FIRST(head)                ((head)->lh_first)
+#define LIST_NEXT(elm, field)           ((elm)->field.le_next)
+
+
+/*
+ * Singly-linked List definitions.
+ */
+#define SLIST_HEAD(name, type)                                          \
+struct name {                                                           \
+        struct type *slh_first; /* first element */                     \
+}
+
+#define SLIST_HEAD_INITIALIZER(head)                                    \
+        { NULL }
+
+#define SLIST_ENTRY(type)                                               \
+struct {                                                                \
+        struct type *sle_next;  /* next element */                      \
+}
+
+/*
+ * Singly-linked List functions.
+ */
+#define SLIST_INIT(head) do {                                           \
+        (head)->slh_first = NULL;                                       \
+} while (/*CONSTCOND*/0)
+
+#define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
+        (elm)->field.sle_next = (slistelm)->field.sle_next;             \
+        (slistelm)->field.sle_next = (elm);                             \
+} while (/*CONSTCOND*/0)
+
+#define SLIST_INSERT_HEAD(head, elm, field) do {                        \
+        (elm)->field.sle_next = (head)->slh_first;                      \
+        (head)->slh_first = (elm);                                      \
+} while (/*CONSTCOND*/0)
+
+#define SLIST_REMOVE_HEAD(head, field) do {                             \
+        (head)->slh_first = (head)->slh_first->field.sle_next;          \
+} while (/*CONSTCOND*/0)
+
+#define SLIST_REMOVE(head, elm, type, field) do {                       \
+        if ((head)->slh_first == (elm)) {                               \
+                SLIST_REMOVE_HEAD((head), field);                       \
+        }                                                               \
+        else {                                                          \
+                struct type *curelm = (head)->slh_first;                \
+                while(curelm->field.sle_next != (elm))                  \
+                        curelm = curelm->field.sle_next;                \
+                curelm->field.sle_next =                                \
+                    curelm->field.sle_next->field.sle_next;             \
+        }                                                               \
+} while (/*CONSTCOND*/0)
+
+#define SLIST_FOREACH(var, head, field)                                 \
+        for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
+
+/*
+ * Singly-linked List access methods.
+ */
+#define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
+#define SLIST_FIRST(head)       ((head)->slh_first)
+#define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
+
+
+/*
+ * Singly-linked Tail queue declarations.
+ */
+#define STAILQ_HEAD(name, type)                                 \
+struct name {                                                           \
+        struct type *stqh_first;        /* first element */                     \
+        struct type **stqh_last;        /* addr of last next element */         \
+}
+
+#define STAILQ_HEAD_INITIALIZER(head)                                   \
+        { NULL, &(head).stqh_first }
+
+#define STAILQ_ENTRY(type)                                              \
+struct {                                                                \
+        struct type *stqe_next; /* next element */                      \
+}
+
+/*
+ * Singly-linked Tail queue functions.
+ */
+#define STAILQ_INIT(head) do {                                          \
+        (head)->stqh_first = NULL;                                      \
+        (head)->stqh_last = &(head)->stqh_first;                                \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
+        if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
+                (head)->stqh_last = &(elm)->field.stqe_next;            \
+        (head)->stqh_first = (elm);                                     \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
+        (elm)->field.stqe_next = NULL;                                  \
+        *(head)->stqh_last = (elm);                                     \
+        (head)->stqh_last = &(elm)->field.stqe_next;                    \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
+        if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
+                (head)->stqh_last = &(elm)->field.stqe_next;            \
+        (listelm)->field.stqe_next = (elm);                             \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_REMOVE_HEAD(head, field) do {                            \
+        if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
+                (head)->stqh_last = &(head)->stqh_first;                        \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_REMOVE(head, elm, type, field) do {                      \
+        if ((head)->stqh_first == (elm)) {                              \
+                STAILQ_REMOVE_HEAD((head), field);                      \
+        } else {                                                        \
+                struct type *curelm = (head)->stqh_first;               \
+                while (curelm->field.stqe_next != (elm))                        \
+                        curelm = curelm->field.stqe_next;               \
+                if ((curelm->field.stqe_next =                          \
+                        curelm->field.stqe_next->field.stqe_next) == NULL) \
+                            (head)->stqh_last = &(curelm)->field.stqe_next; \
+        }                                                               \
+} while (/*CONSTCOND*/0)
+
+#define STAILQ_FOREACH(var, head, field)                                \
+        for ((var) = ((head)->stqh_first);                              \
+                (var);                                                  \
+                (var) = ((var)->field.stqe_next))
+
+#define STAILQ_CONCAT(head1, head2) do {                                \
+        if (!STAILQ_EMPTY((head2))) {                                   \
+                *(head1)->stqh_last = (head2)->stqh_first;              \
+                (head1)->stqh_last = (head2)->stqh_last;                \
+                STAILQ_INIT((head2));                                   \
+        }                                                               \
+} while (/*CONSTCOND*/0)
+
+/*
+ * Singly-linked Tail queue access methods.
+ */
+#define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
+#define STAILQ_FIRST(head)      ((head)->stqh_first)
+#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
+
 
 /*
  * Simple queue definitions.
  */
-#define SIMPLEQ_HEAD(name, type)                                        \
+#define SIMPLEQ_HEAD(name, type)                                        \
 struct name {                                                           \
         struct type *sqh_first; /* first element */                     \
         struct type **sqh_last; /* addr of last next element */         \
 }
 
-#define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
+#define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
         { NULL, &(head).sqh_first }
 
-#define SIMPLEQ_ENTRY(type)                                             \
+#define SIMPLEQ_ENTRY(type)                                             \
 struct {                                                                \
         struct type *sqe_next;  /* next element */                      \
 }
 
 /*
- * Simple queue access methods.
- */
-#define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
-#define SIMPLEQ_END(head)           NULL
-#define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
-#define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
-
-#define SIMPLEQ_FOREACH(var, head, field)                               \
-        for((var) = SIMPLEQ_FIRST(head);                                \
-            (var) != SIMPLEQ_END(head);                                 \
-            (var) = SIMPLEQ_NEXT(var, field))
-
-/*
  * Simple queue functions.
  */
 #define SIMPLEQ_INIT(head) do {                                         \
         (head)->sqh_first = NULL;                                       \
         (head)->sqh_last = &(head)->sqh_first;                          \
-} while (0)
-
-#define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
                 (head)->sqh_last = &(elm)->field.sqe_next;              \
         (head)->sqh_first = (elm);                                      \
-} while (0)
-
-#define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
         (elm)->field.sqe_next = NULL;                                   \
         *(head)->sqh_last = (elm);                                      \
         (head)->sqh_last = &(elm)->field.sqe_next;                      \
-} while (0)
-
-#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
                 (head)->sqh_last = &(elm)->field.sqe_next;              \
         (listelm)->field.sqe_next = (elm);                              \
-} while (0)
-
-#define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {                      \
-        if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)        \
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_REMOVE_HEAD(head, field) do {                           \
+        if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
                 (head)->sqh_last = &(head)->sqh_first;                  \
-} while (0)
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_REMOVE(head, elm, type, field) do {                     \
+        if ((head)->sqh_first == (elm)) {                               \
+                SIMPLEQ_REMOVE_HEAD((head), field);                     \
+        } else {                                                        \
+                struct type *curelm = (head)->sqh_first;                \
+                while (curelm->field.sqe_next != (elm))                 \
+                        curelm = curelm->field.sqe_next;                \
+                if ((curelm->field.sqe_next =                           \
+                        curelm->field.sqe_next->field.sqe_next) == NULL) \
+                            (head)->sqh_last = &(curelm)->field.sqe_next; \
+        }                                                               \
+} while (/*CONSTCOND*/0)
+
+#define SIMPLEQ_FOREACH(var, head, field)                               \
+        for ((var) = ((head)->sqh_first);                               \
+                (var);                                                  \
+                (var) = ((var)->field.sqe_next))
+
+/*
+ * Simple queue access methods.
+ */
+#define SIMPLEQ_EMPTY(head)             ((head)->sqh_first == NULL)
+#define SIMPLEQ_FIRST(head)             ((head)->sqh_first)
+#define SIMPLEQ_NEXT(elm, field)        ((elm)->field.sqe_next)
+
 
 /*
  * Tail queue definitions.
  */
-#define TAILQ_HEAD(name, type)                                          \
-struct name {                                                           \
-        struct type *tqh_first; /* first element */                     \
-        struct type **tqh_last; /* addr of last next element */         \
-}
-
-#define TAILQ_HEAD_INITIALIZER(head)                                    \
+#define _TAILQ_HEAD(name, type, qual)                                   \
+struct name {                                                           \
+        qual type *tqh_first;           /* first element */             \
+        qual type *qual *tqh_last;      /* addr of last next element */ \
+}
+#define TAILQ_HEAD(name, type)  _TAILQ_HEAD(name, struct type,)
+
+#define TAILQ_HEAD_INITIALIZER(head)                                    \
         { NULL, &(head).tqh_first }
 
-#define TAILQ_ENTRY(type)                                               \
-struct {                                                                \
-        struct type *tqe_next;  /* next element */                      \
-        struct type **tqe_prev; /* address of previous next element */  \
-}
-
-/* 
- * tail queue access methods 
- */
-#define TAILQ_FIRST(head)               ((head)->tqh_first)
-#define TAILQ_END(head)                 NULL
-#define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
-#define TAILQ_LAST(head, headname)                                      \
-        (*(((struct headname *)((head)->tqh_last))->tqh_last))
-/* XXX */
-#define TAILQ_PREV(elm, headname, field)                                \
-        (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
-#define TAILQ_EMPTY(head)                                               \
-        (TAILQ_FIRST(head) == TAILQ_END(head))
-
-#define TAILQ_FOREACH(var, head, field)                                 \
-        for((var) = TAILQ_FIRST(head);                                  \
-            (var) != TAILQ_END(head);                                   \
-            (var) = TAILQ_NEXT(var, field))
-
-#define TAILQ_FOREACH_REVERSE(var, head, field, headname)               \
-        for((var) = TAILQ_LAST(head, headname);                         \
-            (var) != TAILQ_END(head);                                   \
-            (var) = TAILQ_PREV(var, headname, field))
+#define _TAILQ_ENTRY(type, qual)                                        \
+struct {                                                                \
+        qual type *tqe_next;            /* next element */              \
+        qual type *qual *tqe_prev;      /* address of previous next element */\
+}
+#define TAILQ_ENTRY(type)       _TAILQ_ENTRY(struct type,)
 
 /*
  * Tail queue functions.
  */
 #define TAILQ_INIT(head) do {                                           \
         (head)->tqh_first = NULL;                                       \
         (head)->tqh_last = &(head)->tqh_first;                          \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
+#define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
                 (head)->tqh_first->field.tqe_prev =                     \
                     &(elm)->field.tqe_next;                             \
         else                                                            \
                 (head)->tqh_last = &(elm)->field.tqe_next;              \
         (head)->tqh_first = (elm);                                      \
         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
+#define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
         (elm)->field.tqe_next = NULL;                                   \
         (elm)->field.tqe_prev = (head)->tqh_last;                       \
         *(head)->tqh_last = (elm);                                      \
         (head)->tqh_last = &(elm)->field.tqe_next;                      \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
+#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
-                (elm)->field.tqe_next->field.tqe_prev =                 \
+                (elm)->field.tqe_next->field.tqe_prev =                 \
                     &(elm)->field.tqe_next;                             \
         else                                                            \
                 (head)->tqh_last = &(elm)->field.tqe_next;              \
         (listelm)->field.tqe_next = (elm);                              \
         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
-} while (0)
+} while (/*CONSTCOND*/0)
 
 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
         (elm)->field.tqe_next = (listelm);                              \
         *(listelm)->field.tqe_prev = (elm);                             \
         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define TAILQ_REMOVE(head, elm, field) do {                             \
+#define TAILQ_REMOVE(head, elm, field) do {                             \
         if (((elm)->field.tqe_next) != NULL)                            \
-                (elm)->field.tqe_next->field.tqe_prev =                 \
+                (elm)->field.tqe_next->field.tqe_prev =                 \
                     (elm)->field.tqe_prev;                              \
         else                                                            \
                 (head)->tqh_last = (elm)->field.tqe_prev;               \
         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
-        if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
-                (elm2)->field.tqe_next->field.tqe_prev =                \
-                    &(elm2)->field.tqe_next;                            \
-        else                                                            \
-                (head)->tqh_last = &(elm2)->field.tqe_next;             \
-        (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
-        *(elm2)->field.tqe_prev = (elm2);                               \
-} while (0)
+#define TAILQ_FOREACH(var, head, field)                                 \
+        for ((var) = ((head)->tqh_first);                               \
+                (var);                                                  \
+                (var) = ((var)->field.tqe_next))
+
+#define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
+        for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
+                (var);                                                  \
+                (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
+
+#define TAILQ_CONCAT(head1, head2, field) do {                          \
+        if (!TAILQ_EMPTY(head2)) {                                      \
+                *(head1)->tqh_last = (head2)->tqh_first;                \
+                (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
+                (head1)->tqh_last = (head2)->tqh_last;                  \
+                TAILQ_INIT((head2));                                    \
+        }                                                               \
+} while (/*CONSTCOND*/0)
+
+/*
+ * Tail queue access methods.
+ */
+#define TAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
+#define TAILQ_FIRST(head)               ((head)->tqh_first)
+#define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
+
+#define TAILQ_LAST(head, headname) \
+        (*(((struct headname *)((head)->tqh_last))->tqh_last))
+#define TAILQ_PREV(elm, headname, field) \
+        (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+
 
 /*
  * Circular queue definitions.
  */
-#define CIRCLEQ_HEAD(name, type)                                        \
+#define CIRCLEQ_HEAD(name, type)                                        \
 struct name {                                                           \
         struct type *cqh_first;         /* first element */             \
         struct type *cqh_last;          /* last element */              \
 }
 
-#define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
-        { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
+#define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
+        { (void *)&head, (void *)&head }
 
-#define CIRCLEQ_ENTRY(type)                                             \
+#define CIRCLEQ_ENTRY(type)                                             \
 struct {                                                                \
         struct type *cqe_next;          /* next element */              \
         struct type *cqe_prev;          /* previous element */          \
 }
 
 /*
- * Circular queue access methods 
- */
-#define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
-#define CIRCLEQ_LAST(head)              ((head)->cqh_last)
-#define CIRCLEQ_END(head)               ((void *)(head))
-#define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
-#define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
-#define CIRCLEQ_EMPTY(head)                                             \
-        (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
-
-#define CIRCLEQ_FOREACH(var, head, field)                               \
-        for((var) = CIRCLEQ_FIRST(head);                                \
-            (var) != CIRCLEQ_END(head);                                 \
-            (var) = CIRCLEQ_NEXT(var, field))
-
-#define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
-        for((var) = CIRCLEQ_LAST(head);                                 \
-            (var) != CIRCLEQ_END(head);                                 \
-            (var) = CIRCLEQ_PREV(var, field))
-
-/*
  * Circular queue functions.
  */
 #define CIRCLEQ_INIT(head) do {                                         \
-        (head)->cqh_first = CIRCLEQ_END(head);                          \
-        (head)->cqh_last = CIRCLEQ_END(head);                           \
-} while (0)
+        (head)->cqh_first = (void *)(head);                             \
+        (head)->cqh_last = (void *)(head);                              \
+} while (/*CONSTCOND*/0)
 
-#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
+#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
         (elm)->field.cqe_prev = (listelm);                              \
-        if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
+        if ((listelm)->field.cqe_next == (void *)(head))                \
                 (head)->cqh_last = (elm);                               \
         else                                                            \
                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
         (listelm)->field.cqe_next = (elm);                              \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
+#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
         (elm)->field.cqe_next = (listelm);                              \
         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
-        if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
+        if ((listelm)->field.cqe_prev == (void *)(head))                \
                 (head)->cqh_first = (elm);                              \
         else                                                            \
                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
         (listelm)->field.cqe_prev = (elm);                              \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
+#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
         (elm)->field.cqe_next = (head)->cqh_first;                      \
-        (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
-        if ((head)->cqh_last == CIRCLEQ_END(head))                      \
+        (elm)->field.cqe_prev = (void *)(head);                         \
+        if ((head)->cqh_last == (void *)(head))                         \
                 (head)->cqh_last = (elm);                               \
         else                                                            \
                 (head)->cqh_first->field.cqe_prev = (elm);              \
         (head)->cqh_first = (elm);                                      \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
-        (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
+#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
+        (elm)->field.cqe_next = (void *)(head);                         \
         (elm)->field.cqe_prev = (head)->cqh_last;                       \
-        if ((head)->cqh_first == CIRCLEQ_END(head))                     \
+        if ((head)->cqh_first == (void *)(head))                        \
                 (head)->cqh_first = (elm);                              \
         else                                                            \
                 (head)->cqh_last->field.cqe_next = (elm);               \
         (head)->cqh_last = (elm);                                       \
-} while (0)
+} while (/*CONSTCOND*/0)
 
 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
-        if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
+        if ((elm)->field.cqe_next == (void *)(head))                    \
                 (head)->cqh_last = (elm)->field.cqe_prev;               \
         else                                                            \
                 (elm)->field.cqe_next->field.cqe_prev =                 \
                     (elm)->field.cqe_prev;                              \
-        if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
+        if ((elm)->field.cqe_prev == (void *)(head))                    \
                 (head)->cqh_first = (elm)->field.cqe_next;              \
         else                                                            \
                 (elm)->field.cqe_prev->field.cqe_next =                 \
                     (elm)->field.cqe_next;                              \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
-        if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
-            CIRCLEQ_END(head))                                          \
-                (head).cqh_last = (elm2);                               \
-        else                                                            \
-                (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
-        if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
-            CIRCLEQ_END(head))                                          \
-                (head).cqh_first = (elm2);                              \
-        else                                                            \
-                (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
-} while (0)
+#define CIRCLEQ_FOREACH(var, head, field)                               \
+        for ((var) = ((head)->cqh_first);                               \
+                (var) != (const void *)(head);                          \
+                (var) = ((var)->field.cqe_next))
 
-#endif  /* !_SYS_QUEUE_H_ */
+#define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
+        for ((var) = ((head)->cqh_last);                                \
+                (var) != (const void *)(head);                          \
+                (var) = ((var)->field.cqe_prev))
+
+/*
+ * Circular queue access methods.
+ */
+#define CIRCLEQ_EMPTY(head)             ((head)->cqh_first == (void *)(head))
+#define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
+#define CIRCLEQ_LAST(head)              ((head)->cqh_last)
+#define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
+#define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
+
+#define CIRCLEQ_LOOP_NEXT(head, elm, field)                             \
+        (((elm)->field.cqe_next == (void *)(head))                      \
+            ? ((head)->cqh_first)                                       \
+            : (elm->field.cqe_next))
+#define CIRCLEQ_LOOP_PREV(head, elm, field)                             \
+        (((elm)->field.cqe_prev == (void *)(head))                      \
+            ? ((head)->cqh_last)                                        \
+            : (elm->field.cqe_prev))
+
+#endif  /* sys/queue.h */