xref: /illumos-gate/usr/src/lib/libc/port/gen/isastream.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 
33 /*
34  * Check to see if a file descriptor is that of a stream.
35  * Return 1 with errno set to 0 if it is. Otherwise,
36  * return 0 with errno set to 0.
37  * The only error returned is that case of a bad file desc.
38  *
39  */
40 
41 #pragma weak isastream = _isastream
42 
43 #include "synonyms.h"
44 #include <sys/types.h>
45 #include <stdio.h>
46 #include <errno.h>
47 #include <stropts.h>
48 
49 int
50 isastream(int fd)
51 {
52 	int rval;
53 
54 	rval = ioctl(fd, I_CANPUT, 0);
55 	if (rval == -1 && errno == EBADF)
56 		return (-1);
57 
58 	errno = 0;
59 	if (rval == 0 || rval == 1)
60 		return (1);
61 
62 	return (0);
63 }
64