unlockpt.c 1.5 KB

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  1. /* Copyright (C) 1998 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Library General Public License as
  6. published by the Free Software Foundation; either version 2 of the
  7. License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Library General Public License for more details.
  12. You should have received a copy of the GNU Library General Public
  13. License along with the GNU C Library; see the file COPYING.LIB. If not,
  14. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  15. Boston, MA 02111-1307, USA. */
  16. #include <errno.h>
  17. #include <stdlib.h>
  18. #include <sys/ioctl.h>
  19. #include <termios.h>
  20. libc_hidden_proto(ioctl)
  21. /* Unlock the slave pseudo terminal associated with the master pseudo
  22. terminal specified by FD. */
  23. int
  24. unlockpt (int fd)
  25. {
  26. #ifdef TIOCSPTLCK
  27. int save_errno = errno;
  28. int unlock = 0;
  29. if (ioctl (fd, TIOCSPTLCK, &unlock))
  30. {
  31. if (errno == EINVAL)
  32. {
  33. errno = save_errno;
  34. return 0;
  35. }
  36. else
  37. return -1;
  38. }
  39. #endif
  40. /* If we have no TIOCSPTLCK ioctl, all slave pseudo terminals are
  41. unlocked by default. */
  42. return 0;
  43. }