logname.c revision 1.4 
1/*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35char copyright[] =
36"@(#) Copyright (c) 1991 The Regents of the University of California.\n\
37 All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41/*static char sccsid[] = "from: @(#)logname.c	5.1 (Berkeley) 6/28/91";*/
42static char rcsid[] = "$Id: logname.c,v 1.4 1993/12/31 19:27:18 jtc Exp $";
43#endif /* not lint */
44
45#include <errno.h>
46#include <unistd.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50
51void usage __P((void));
52
53main(argc, argv)
54	int argc;
55	char *argv[];
56{
57	char *p;
58
59	if (argc != 1) {
60		usage();
61	}
62
63	if ((p = getlogin()) == NULL) {
64		(void)fprintf(stderr, "logname: %s\n", strerror(errno));
65		exit(1);
66	}
67	(void)printf("%s\n", p);
68	exit(0);
69}
70
71void
72usage()
73{
74	(void)fprintf(stderr, "usage: logname\n");
75	exit(1);
76}
77