glibc/sysdeps/unix/bsd/tcflush.c

/* Copyright (C) 1991-2017 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <stddef.h>
#include <termios.h>
#include <unistd.h>
#include "bsdtty.h"
#include <sys/file.h>

/* Flush pending data on FD.  */
int
tcflush (int fd, int queue_selector)
{
  int arg;

  switch (queue_selector)
    {
    case TCIFLUSH:
      arg = FREAD;
      break;
    case TCOFLUSH:
      arg = FWRITE;
      break;
    case TCIOFLUSH:
      arg = FREAD | FWRITE;
      break;
    default:
      __set_errno (EINVAL);
      return -1;
    }

  return __ioctl (fd, TIOCFLUSH, (void *) &arg);
}