sysdeps/unix/bsd/tcflow.c

   1 /* Copyright (C) 1991, 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 <termios.h>
  23 #include <unistd.h>
  24
  25 #include "bsdtty.h"
  26
  27 /* Suspend or restart transmission on FD.  */
  28 int
  29 DEFUN(tcflow, (fd, action), int fd AND int action)
  30 {
  31   switch (action)
  32     {
  33     case TCOOFF:
  34       return __ioctl(fd, TIOCSTOP, (PTR) NULL);
  35     case TCOON:
  36       return __ioctl(fd, TIOCSTART, (PTR) 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       errno = EINVAL;
  55       return -1;
  56     }
  57 }