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Annotation of 43BSDReno/usr.bin/make/lst.lib/lstDeQueue.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Adam de Boor.
                      7:  *
                      8:  * Redistribution and use in source and binary forms are permitted
                      9:  * provided that: (1) source distributions retain this entire copyright
                     10:  * notice and comment, and (2) distributions including binaries display
                     11:  * the following acknowledgement:  ``This product includes software
                     12:  * developed by the University of California, Berkeley and its contributors''
                     13:  * in the documentation or other materials provided with the distribution
                     14:  * and in all advertising materials mentioning features or use of this
                     15:  * software. Neither the name of the University nor the names of its
                     16:  * contributors may be used to endorse or promote products derived
                     17:  * from this software without specific prior written permission.
                     18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     19:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     20:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     21:  */
                     22: 
                     23: #ifndef lint
                     24: static char sccsid[] = "@(#)lstDeQueue.c       5.3 (Berkeley) 6/1/90";
                     25: #endif /* not lint */
                     26: 
                     27: /*-
                     28:  * LstDeQueue.c --
                     29:  *     Remove the node and return its datum from the head of the list
                     30:  */
                     31: 
                     32: #include       "lstInt.h"
                     33: 
                     34: /*-
                     35:  *-----------------------------------------------------------------------
                     36:  * Lst_DeQueue --
                     37:  *     Remove and return the datum at the head of the given list.
                     38:  *
                     39:  * Results:
                     40:  *     The datum in the node at the head or (ick) NIL if the list
                     41:  *     is empty.
                     42:  *
                     43:  * Side Effects:
                     44:  *     The head node is removed from the list.
                     45:  *
                     46:  *-----------------------------------------------------------------------
                     47:  */
                     48: ClientData
                     49: Lst_DeQueue (l)
                     50:     Lst                  l;
                     51: {
                     52:     ClientData   rd;
                     53:     register ListNode  tln;
                     54:     
                     55:     tln = (ListNode) Lst_First (l);
                     56:     if (tln == NilListNode) {
                     57:        return ((ClientData) NIL);
                     58:     }
                     59:     
                     60:     rd = tln->datum;
                     61:     if (Lst_Remove (l, (LstNode)tln) == FAILURE) {
                     62:        return ((ClientData) NIL);
                     63:     } else {
                     64:        return (rd);
                     65:     }
                     66: }
                     67: 

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