i386/gen/remque.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1992, 1997  NeXT Software, Inc.  All rights reserved.
  23  *
  24  *      File:   libc/gen/ppc/remque.c
  25  *
  26  * struct qelem {
  27  *      struct qelem    *q_forw;
  28  *      struct qelem    *q_back;
  29  *      char            q_data[];
  30  * };
  31  *
  32  * void remque(struct qelem *entry);
  33  *
  34  * Removes `entry' from a queue.
  35  *
  36  * HISTORY
  37  *  24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com)
  38  *      Ported to PPC.
  39  *  10-Nov-92  Derek B Clegg (dclegg@next.com)
  40  *      Created.
  41  */
  42 #import <libc.h>
  43
  44 void
  45 remque(struct qelem *elem)
  46 {
  47     struct qelem *next, *prev;
  48
  49     next = elem->q_forw;
  50     prev = elem->q_back;
  51     if (next != 0)
  52         next->q_back = prev;
  53     if (prev != 0)
  54         prev->q_forw = next;
  55 }