xref: /illumos-gate/usr/src/lib/libc/port/gen/isastream.c (revision 1da57d55)
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 /*
31  * Check to see if a file descriptor is that of a stream.
32  * Return 1 with errno set to 0 if it is. Otherwise,
33  * return 0 with errno set to 0.
34  * The only error returned is that case of a bad file desc.
35  *
36  */
37 
38 #pragma weak _isastream = isastream
39 
40 #include "lint.h"
41 #include <sys/types.h>
42 #include <stdio.h>
43 #include <errno.h>
44 #include <stropts.h>
45 
46 int
isastream(int fd)47 isastream(int fd)
48 {
49 	int rval;
50 
51 	rval = ioctl(fd, I_CANPUT, 0);
52 	if (rval == -1 && errno == EBADF)
53 		return (-1);
54 
55 	errno = 0;
56 	if (rval == 0 || rval == 1)
57 		return (1);
58 
59 	return (0);
60 }
61