glibc/misc/insremque.c

50 lines
1.4 KiB
C

/* Copyright (C) 1992, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <stddef.h>
#include <search.h>
/* Insert ELEM into a doubly-linked list, after PREV. */
void
DEFUN(insque, (elem, prev) ,
struct qelem *elem AND struct qelem *prev)
{
struct qelem *next = prev->q_forw;
prev->q_forw = elem;
if (next != NULL)
next->q_back = elem;
elem->q_forw = next;
elem->q_back = prev;
}
/* Unlink ELEM from the doubly-linked list that it is in. */
void
DEFUN(remque, (elem),
struct qelem *elem)
{
struct qelem *next = elem->q_forw;
struct qelem *prev = elem->q_back;
if (next != NULL)
next->q_back = prev;
if (prev != NULL)
prev->q_forw = next;
}