140412Sbostic /* 262085Sbostic * Copyright (c) 1988, 1989, 1990, 1993 362085Sbostic * The Regents of the University of California. All rights reserved. 440411Sbostic * 540412Sbostic * This code is derived from software contributed to Berkeley by 640412Sbostic * Adam de Boor. 740411Sbostic * 842741Sbostic * %sccs.include.redist.c% 940411Sbostic */ 1040412Sbostic 1140411Sbostic #ifndef lint 12*69094Schristos static char sccsid[] = "@(#)lstDeQueue.c 8.2 (Berkeley) 04/28/95"; 1340412Sbostic #endif /* not lint */ 1440411Sbostic 1540412Sbostic /*- 1640412Sbostic * LstDeQueue.c -- 1740412Sbostic * Remove the node and return its datum from the head of the list 1840412Sbostic */ 1940412Sbostic 2040411Sbostic #include "lstInt.h" 2140411Sbostic 2240411Sbostic /*- 2340411Sbostic *----------------------------------------------------------------------- 2440411Sbostic * Lst_DeQueue -- 2540411Sbostic * Remove and return the datum at the head of the given list. 2640411Sbostic * 2740411Sbostic * Results: 2840411Sbostic * The datum in the node at the head or (ick) NIL if the list 2940411Sbostic * is empty. 3040411Sbostic * 3140411Sbostic * Side Effects: 3240411Sbostic * The head node is removed from the list. 3340411Sbostic * 3440411Sbostic *----------------------------------------------------------------------- 3540411Sbostic */ 3640411Sbostic ClientData Lst_DeQueue(l)3740411SbosticLst_DeQueue (l) 3840411Sbostic Lst l; 3940411Sbostic { 4040411Sbostic ClientData rd; 4140411Sbostic register ListNode tln; 4240411Sbostic 4340411Sbostic tln = (ListNode) Lst_First (l); 4440411Sbostic if (tln == NilListNode) { 4540411Sbostic return ((ClientData) NIL); 4640411Sbostic } 4740411Sbostic 4840411Sbostic rd = tln->datum; 4940411Sbostic if (Lst_Remove (l, (LstNode)tln) == FAILURE) { 5040411Sbostic return ((ClientData) NIL); 5140411Sbostic } else { 5240411Sbostic return (rd); 5340411Sbostic } 5440411Sbostic } 5540411Sbostic 56