1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 #pragma ident "%Z%%M% %I% %E% SMI"
31
32 /*
33 * Check to see if a file descriptor is that of a stream.
34 * Return 1 with errno set to 0 if it is. Otherwise,
35 * return 0 with errno set to 0.
36 * The only error returned is that case of a bad file desc.
37 *
38 */
39
40 #pragma weak _isastream = isastream
41
42 #include "lint.h"
43 #include <sys/types.h>
44 #include <stdio.h>
45 #include <errno.h>
46 #include <stropts.h>
47
48 int
isastream(int fd)49 isastream(int fd)
50 {
51 int rval;
52
53 rval = ioctl(fd, I_CANPUT, 0);
54 if (rval == -1 && errno == EBADF)
55 return (-1);
56
57 errno = 0;
58 if (rval == 0 || rval == 1)
59 return (1);
60
61 return (0);
62 }
63