ftello.c 2.2 KB

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  1. /* Copyright (C) 1993-2019 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>.
  14. As a special exception, if you link the code in this file with
  15. files compiled with a GNU compiler to produce an executable,
  16. that does not cause the resulting executable to be covered by
  17. the GNU Lesser General Public License. This exception does not
  18. however invalidate any other reasons why the executable file
  19. might be covered by the GNU Lesser General Public License.
  20. This exception applies to code released by its copyright holders
  21. in files containing the exception. */
  22. /* We need to disable the redirect for __ftello64 for the alias
  23. definitions below to work. */
  24. #define __ftello64 __ftello64_disable
  25. #include <stdio.h>
  26. #include <stdlib.h>
  27. #include <libioP.h>
  28. #include <errno.h>
  29. off_t
  30. __ftello (FILE *fp)
  31. {
  32. off64_t pos;
  33. CHECK_FILE (fp, -1L);
  34. _IO_acquire_lock (fp);
  35. pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
  36. if (_IO_in_backup (fp) && pos != _IO_pos_BAD)
  37. {
  38. if (fp->_mode <= 0)
  39. pos -= fp->_IO_save_end - fp->_IO_save_base;
  40. }
  41. _IO_release_lock (fp);
  42. if (pos == _IO_pos_BAD)
  43. {
  44. if (errno == 0)
  45. __set_errno (EIO);
  46. return -1L;
  47. }
  48. if ((off64_t) (off_t) pos != pos)
  49. {
  50. __set_errno (EOVERFLOW);
  51. return -1L;
  52. }
  53. return pos;
  54. }
  55. libc_hidden_def (__ftello)
  56. weak_alias (__ftello, ftello)
  57. #ifdef __OFF_T_MATCHES_OFF64_T
  58. weak_alias (__ftello, ftello64)
  59. # undef __ftello64
  60. strong_alias (__ftello, __ftello64)
  61. libc_hidden_ver (__ftello, __ftello64)
  62. #endif