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[glibc.git] / misc / insremque.c
blobe366ac806357ae42a90f8c1bdb3cf289e8cfcff1
1 /* Copyright (C) 1992, 1995, 1996 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <stddef.h>
20 #include <search.h>
22 /* Insert ELEM into a doubly-linked list, after PREV. */
24 void
25 insque (void *elem, void *prev)
27 struct qelem *next = ((struct qelem *) prev)->q_forw;
28 ((struct qelem *) prev)->q_forw = (struct qelem *) elem;
29 if (next != NULL)
30 next->q_back = (struct qelem *) elem;
31 ((struct qelem *) elem)->q_forw = next;
32 ((struct qelem *) elem)->q_back = (struct qelem *) prev;
35 /* Unlink ELEM from the doubly-linked list that it is in. */
37 void
38 remque (void *elem)
40 struct qelem *next = ((struct qelem *) elem)->q_forw;
41 struct qelem *prev = ((struct qelem *) elem)->q_back;
42 if (next != NULL)
43 next->q_back = prev;
44 if (prev != NULL)
45 prev->q_forw = (struct qelem *) next;