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. /* Unlock the slave pseudo terminal associated with the master pseudo
  21. terminal specified by FD. */
  22. int
  23. unlockpt (int fd)
  24. {
  25. #ifdef TIOCSPTLCK
  26. int save_errno = errno;
  27. int unlock = 0;
  28. if (__ioctl (fd, TIOCSPTLCK, &unlock))
  29. {
  30. if (errno == EINVAL)
  31. {
  32. errno = save_errno;
  33. return 0;
  34. }
  35. else
  36. return -1;
  37. }
  38. #endif
  39. /* If we have no TIOCSPTLCK ioctl, all slave pseudo terminals are
  40. unlocked by default. */
  41. return 0;
  42. }