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glibc  2.9
insremque.c
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00001 /* Copyright (C) 1992, 1995, 1996, 2006 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <stddef.h>
00020 #include <search.h>
00021 
00022 /* Insert ELEM into a doubly-linked list, after PREV.  */
00023 
00024 void
00025 insque (void *elem, void *prev)
00026 {
00027   if (prev == NULL)
00028     {
00029       ((struct qelem *) elem)->q_forw = NULL;
00030       ((struct qelem *) elem)->q_back = NULL;
00031     }
00032   else
00033     {
00034       struct qelem *next = ((struct qelem *) prev)->q_forw;
00035       ((struct qelem *) prev)->q_forw = (struct qelem *) elem;
00036       if (next != NULL)
00037        next->q_back = (struct qelem *) elem;
00038       ((struct qelem *) elem)->q_forw = next;
00039       ((struct qelem *) elem)->q_back = (struct qelem *) prev;
00040     }
00041 }
00042 
00043 /* Unlink ELEM from the doubly-linked list that it is in.  */
00044 
00045 void
00046 remque (void *elem)
00047 {
00048   struct qelem *next = ((struct qelem *) elem)->q_forw;
00049   struct qelem *prev = ((struct qelem *) elem)->q_back;
00050   if (next != NULL)
00051     next->q_back = prev;
00052   if (prev != NULL)
00053     prev->q_forw = (struct qelem *) next;
00054 }