minix/commands/make/lst.lib/lstPrev.c

79 lines
2.6 KiB
C

/* $NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl 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.
*/
#ifndef MAKE_NATIVE
static char rcsid[] = "$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)lstSucc.c 8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $");
#endif
#endif /* not lint */
#endif
/*-
* LstPrev.c --
* return the predecessor to a given node
*/
#include "lstInt.h"
/*-
*-----------------------------------------------------------------------
* Lst_Prev --
* Return the predecessor to the given node on its list.
*
* Results:
* The predecessor of the node, if it exists (note that on a circular
* list, if the node is the only one in the list, it is its own
* predecessor).
*
* Side Effects:
* None.
*
*-----------------------------------------------------------------------
*/
LstNode
Lst_Prev(LstNode ln)
{
if (ln == NULL) {
return NULL;
} else {
return (ln->prevPtr);
}
}