tcsendbrk.c 1.7 KB

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  1. /* Send break to terminal.
  2. Copyright (C) 1996, 1997 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the 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. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include <errno.h>
  17. #include <stddef.h>
  18. #include <termios.h>
  19. #include <sys/ioctl.h>
  20. /* Send zero bits on FD. */
  21. int
  22. tcsendbreak (int fd, int duration)
  23. {
  24. /* The break lasts 0.25 to 0.5 seconds if DURATION is zero,
  25. and an implementation-defined period if DURATION is nonzero.
  26. We define a positive DURATION to be number of milliseconds to break. */
  27. if (duration <= 0)
  28. return ioctl (fd, TCSBRK, 0);
  29. #ifdef TCSBRKP
  30. /* Probably Linux-specific: a positive third TCSBRKP ioctl argument is
  31. defined to be the number of 100ms units to break. */
  32. return ioctl (fd, TCSBRKP, (duration + 99) / 100);
  33. #else
  34. /* ioctl can't send a break of any other duration for us.
  35. This could be changed to use trickery (e.g. lower speed and
  36. send a '\0') to send the break, but for now just return an error. */
  37. __set_errno (EINVAL);
  38. return -1;
  39. #endif
  40. }