usr/src/lib/libbc/libc/stdio/common/ftell.c

   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 }