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/* $OpenBSD: lstDeQueue.c,v 1.19 2010/07/19 19:46:44 espie Exp $ */
/* $NetBSD: lstDeQueue.c,v 1.5 1996/11/06 17:59:36 christos Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Adam de Boor.
*
* 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
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*-
* LstDeQueue.c --
* Remove the node and return its datum from the head of the list
*/
#include "lstInt.h"
#include <stdlib.h>
/*-
*-----------------------------------------------------------------------
* Lst_DeQueue --
* Remove and return the datum at the head of the given list.
*
* Results:
* The datum in the node at the head or NULL if the list is empty.
*
* Side Effects:
* The head node is removed from the list.
*-----------------------------------------------------------------------
*/
void *
Lst_DeQueue(Lst l)
{
void *rd;
LstNode tln;
tln = l->firstPtr;
if (tln == NULL)
return NULL;
rd = tln->datum;
l->firstPtr = tln->nextPtr;
if (l->firstPtr)
l->firstPtr->prevPtr = NULL;
else
l->lastPtr = NULL;
free(tln);
return rd;
}
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