tcflow.c

来自「一个C源代码分析器」· C语言 代码 · 共 58 行

/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <errno.h>
#include <stddef.h>
#include <termios.h>
#include <unistd.h>

#include "bsdtty.h"

/* Suspend or restart transmission on FD.  */
int
DEFUN(tcflow, (fd, action), int fd AND int action)
{
  switch (action)
    {
    case TCOOFF:
      return __ioctl(fd, TIOCSTOP, (PTR) NULL);
    case TCOON:
      return __ioctl(fd, TIOCSTART, (PTR) NULL);

    case TCIOFF:
    case TCION:
      {
	/* This just writes the START or STOP character with
	   `write'.  Is there another way to do this?  */
	struct termios attr;
	unsigned char c;
	if (tcgetattr(fd, &attr) < 0)
	  return -1;
	c = attr.c_cc[action == TCIOFF ? VSTOP : VSTART];
	if (c != _POSIX_VDISABLE && write (fd, &c, 1) < 1)
	  return -1;
	return 0;
      }

    default:
      errno = EINVAL;
      return -1;
    }
}