sysdeps/unix/bsd/tcflow.c

   1 /* Copyright (C) 1991-2013 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 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
   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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <stddef.h>
  20 #include <termios.h>
  21 #include <unistd.h>
  22
  23 #include "bsdtty.h"
  24
  25 /* Suspend or restart transmission on FD.  */
  26 int
  27 tcflow (fd, action)
  28      int fd;
  29      int action;
  30 {
  31   switch (action)
  32     {
  33     case TCOOFF:
  34       return __ioctl (fd, TIOCSTOP, (void *) NULL);
  35     case TCOON:
  36       return __ioctl (fd, TIOCSTART, (void *) NULL);
  37
  38     case TCIOFF:
  39     case TCION:
  40       {
  41         /* This just writes the START or STOP character with
  42            `write'.  Is there another way to do this?  */
  43         struct termios attr;
  44         unsigned char c;
  45         if (tcgetattr (fd, &attr) < 0)
  46           return -1;
  47         c = attr.c_cc[action == TCIOFF ? VSTOP : VSTART];
  48         if (c != _POSIX_VDISABLE && write (fd, &c, 1) < 1)
  49           return -1;
  50         return 0;
  51       }
  52
  53     default:
  54       __set_errno (EINVAL);
  55       return -1;
  56     }
  57 }