sysdeps/unix/sysv/tcsendbrk.c

   1 /* Copyright (C) 1992 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   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
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <termios.h>
  24 #include <unistd.h>
  25 #include <sysv_termio.h>
  26 #include <sys/ioctl.h>
  27
  28 /* Send zero bits on FD.  */
  29 int
  30 DEFUN(tcsendbreak, (fd, duration), int fd AND int duration)
  31 {
  32   /* The break lasts 0.25 to 0.5 seconds if DURATION is zero,
  33      and an implementation-defined period if DURATION is nonzero.
  34      We define a positive DURATION to be number of milliseconds to break.  */
  35   if (duration <= 0)
  36     return __ioctl (fd, _TCSBRK, 0);
  37
  38   /* ioctl can't send a break of any other duration for us.
  39      This could be changed to use trickery (e.g. lower speed and
  40      send a '\0') to send the break, but for now just return an error.  */
  41   errno = EINVAL;
  42   return -1;
  43 }