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glibc  2.9
tcsendbrk.c
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00001 /* Copyright (C) 1992, 1996, 1997 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <stddef.h>
00021 #include <signal.h>
00022 #include <termios.h>
00023 #include <unistd.h>
00024 #include <sysv_termio.h>
00025 #include <sys/ioctl.h>
00026 
00027 /* Send zero bits on FD.  */
00028 int
00029 tcsendbreak (fd, duration)
00030      int fd;
00031      int duration;
00032 {
00033   /* The break lasts 0.25 to 0.5 seconds if DURATION is zero,
00034      and an implementation-defined period if DURATION is nonzero.
00035      We define a positive DURATION to be number of milliseconds to break.  */
00036   if (duration <= 0)
00037     return __ioctl (fd, _TCSBRK, 0);
00038 
00039   /* ioctl can't send a break of any other duration for us.
00040      This could be changed to use trickery (e.g. lower speed and
00041      send a '\0') to send the break, but for now just return an error.  */
00042   __set_errno (EINVAL);
00043   return -1;
00044 }