source: rtems/cpukit/libcsupport/src/lseek.c @ 690861c

4.104.114.84.95
Last change on this file since 690861c was 0eae36c7, checked in by Joel Sherrill <joel.sherrill@…>, on 09/04/03 at 18:54:13

2003-09-04 Joel Sherrill <joel@…>

  • include/chain.h, include/clockdrv.h, include/console.h, include/iosupp.h, include/rtc.h, include/spurious.h, include/timerdrv.h, include/vmeintr.h, include/motorola/mc68230.h, include/rtems/libcsupport.h, include/rtems/libio.h, include/rtems/libio_.h, include/rtems/termiostypes.h, include/sys/termios.h, include/zilog/z8036.h, include/zilog/z8530.h, include/zilog/z8536.h, src/brk.c, src/gettod.c, src/sbrk.c, src/times.c, src/access.c, src/base_fs.c, src/cfgetispeed.c, src/cfgetospeed.c, src/cfsetispeed.c, src/cfsetospeed.c, src/chdir.c, src/chmod.c, src/chown.c, src/chroot.c, src/close.c, src/ctermid.c, src/dup.c, src/dup2.c, src/eval.c, src/fchdir.c, src/fchmod.c, src/fcntl.c, src/fdatasync.c, src/fpathconf.c, src/fs_null_handlers.c, src/fstat.c, src/fsync.c, src/ftruncate.c, src/getdents.c, src/getpwent.c, src/hosterr.c, src/ioctl.c, src/isatty.c, src/libio.c, src/libio_sockets.c, src/link.c, src/lseek.c, src/lstat.c, src/malloc.c, src/mallocfreespace.c, src/mkdir.c, src/mkfifo.c, src/mknod.c, src/mount.c, src/newlibc.c, src/no_libc.c, src/no_posix.c, src/open.c, src/pathconf.c, src/pipe.c, src/privateenv.c, src/read.c, src/readlink.c, src/rewinddir.c, src/rmdir.c, src/seekdir.c, src/stat.c, src/symlink.c, src/sync.c, src/tcdrain.c, src/tcflow.c, src/tcflush.c, src/tcgetattr.c, src/tcgetprgrp.c, src/tcsendbreak.c, src/tcsetattr.c, src/tcsetpgrp.c, src/telldir.c, src/termios.c, src/termiosinitialize.c, src/truncate.c, src/umask.c, src/unixlibc.c, src/unlink.c, src/unmount.c, src/utime.c, src/write.c: URL for license changed.
  • Property mode set to 100644
File size: 1.8 KB
Line 
1/*
2 *  lseek() - POSIX 1003.1b 6.5.3 - Reposition Read/Write File Offset
3 *
4 *  COPYRIGHT (c) 1989-1999.
5 *  On-Line Applications Research Corporation (OAR).
6 *
7 *  The license and distribution terms for this file may be
8 *  found in the file LICENSE in this distribution or at
9 *  http://www.rtems.com/license/LICENSE.
10 *
11 *  $Id$
12 */
13
14#if HAVE_CONFIG_H
15#include "config.h"
16#endif
17
18#include <stdio.h>
19
20#include <rtems/libio_.h>
21#include <rtems/seterr.h>
22
23off_t lseek(
24  int     fd,
25  off_t   offset,
26  int     whence
27)
28{
29  rtems_libio_t *iop;
30  off_t          old_offset;
31  off_t          status;
32
33  rtems_libio_check_fd( fd );
34  iop = rtems_libio_iop( fd );
35  rtems_libio_check_is_open(iop);
36
37  /*
38   *  Check as many errors as possible before touching iop->offset.
39   */
40
41  if ( !iop->handlers->lseek_h )
42    rtems_set_errno_and_return_minus_one( ENOTSUP );
43
44  /*
45   *  Now process the lseek().
46   */
47
48  old_offset = iop->offset;
49  switch ( whence ) {
50    case SEEK_SET:
51      iop->offset = offset;
52      break;
53
54    case SEEK_CUR:
55      iop->offset += offset;
56      break;
57
58    case SEEK_END:
59      iop->offset = iop->size + offset;
60      break;
61
62    default:
63      rtems_set_errno_and_return_minus_one( EINVAL );
64  }
65
66  /*
67   *  At this time, handlers assume iop->offset has the desired
68   *  new offset.
69   */
70
71  status = (*iop->handlers->lseek_h)( iop, offset, whence );
72  if ( status == (off_t) -1 )
73    iop->offset = old_offset;
74
75  /*
76   *  So if the operation failed, we have to restore iop->offset.
77   */
78
79  return status;
80}
81
82/*
83 *  _lseek_r
84 *
85 *  This is the Newlib dependent reentrant version of lseek().
86 */
87
88#if defined(RTEMS_NEWLIB)
89
90#include <reent.h>
91
92off_t _lseek_r(
93  struct _reent *ptr,
94  int            fd,
95  off_t          offset,
96  int            whence
97)
98{
99  return lseek( fd, offset, whence );
100}
101#endif
102
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