xref: /titanic_41/usr/src/lib/libbc/libc/stdio/common/ftell.c (revision fcf3ce441efd61da9bb2884968af01cb7c1452cc)
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 1986 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*      Copyright (c) 1984 AT&T */
28 /*        All Rights Reserved   */
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.2 */
31 
32 /*LINTLIBRARY*/
33 /*
34  * Return file offset.
35  * Coordinates with buffering.
36  */
37 #include <stdio.h>
38 
39 extern long lseek();
40 
41 long
42 ftell(iop)
43 register FILE *iop;
44 {
45 	register long tres;
46 	register int adjust;
47 
48 	if(iop->_cnt < 0)
49 		iop->_cnt = 0;
50 	if(iop->_flag & _IOREAD)
51 		adjust = - iop->_cnt;
52 	else if(iop->_flag & (_IOWRT | _IORW)) {
53 		adjust = 0;
54 		if(iop->_flag & _IOWRT && iop->_base &&
55 					(iop->_flag & _IONBF) == 0)
56 			adjust = iop->_ptr - iop->_base;
57 	} else
58 		return(-1);
59 	tres = lseek(fileno(iop), 0L, 1);
60 	if(tres >= 0)
61 		tres += (long)adjust;
62 	return(tres);
63 }
64