NetBSD/usr.bin/make/lst.lib/lstDeQueue.c

83 lines
2.9 KiB
C

/*
* Copyright (c) 1988, 1989, 1990 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
/*static char sccsid[] = "from: @(#)lstDeQueue.c 5.3 (Berkeley) 6/1/90";*/
static char rcsid[] = "$Id: lstDeQueue.c,v 1.2 1993/08/01 18:12:34 mycroft Exp $";
#endif /* not lint */
/*-
* LstDeQueue.c --
* Remove the node and return its datum from the head of the list
*/
#include "lstInt.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 (ick) NIL if the list
* is empty.
*
* Side Effects:
* The head node is removed from the list.
*
*-----------------------------------------------------------------------
*/
ClientData
Lst_DeQueue (l)
Lst l;
{
ClientData rd;
register ListNode tln;
tln = (ListNode) Lst_First (l);
if (tln == NilListNode) {
return ((ClientData) NIL);
}
rd = tln->datum;
if (Lst_Remove (l, (LstNode)tln) == FAILURE) {
return ((ClientData) NIL);
} else {
return (rd);
}
}