1 /*-
2  * LstFirst.c --
3  *	Return the first node of a list
4  *
5  * Copyright (c) 1988 by University of California Regents
6  *
7  * Permission to use, copy, modify, and distribute this
8  * software and its documentation for any purpose and without
9  * fee is hereby granted, provided that the above copyright
10  * notice appears in all copies.  Neither the University of California nor
11  * Adam de Boor makes any representations about the suitability of this
12  * software for any purpose.  It is provided "as is" without
13  * express or implied warranty.
14  */
15 #ifndef lint
16 static char *rcsid =
17 "$Id: lstFirst.c,v 1.5 88/11/17 20:52:44 adam Exp $ SPRITE (Berkeley)";
18 #endif lint
19 
20 #include	"lstInt.h"
21 
22 /*-
23  *-----------------------------------------------------------------------
24  * Lst_First --
25  *	Return the first node on the given list.
26  *
27  * Results:
28  *	The first node or NILLNODE if the list is empty.
29  *
30  * Side Effects:
31  *	None.
32  *
33  *-----------------------------------------------------------------------
34  */
35 LstNode
36 Lst_First (l)
37     Lst	l;
38 {
39     if (!LstValid (l) || LstIsEmpty (l)) {
40 	return (NILLNODE);
41     } else {
42 	return ((LstNode)((List)l)->firstPtr);
43     }
44 }
45 
46