1  /* Copyright (C) 1991-2023 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     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include <stddef.h>
      20  #include <termios.h>
      21  #include <unistd.h>
      22  #include "bsdtty.h"
      23  #include <sys/file.h>
      24  
      25  /* Flush pending data on FD.  */
      26  int
      27  tcflush (int fd, int queue_selector)
      28  {
      29    int arg;
      30  
      31    switch (queue_selector)
      32      {
      33      case TCIFLUSH:
      34        arg = FREAD;
      35        break;
      36      case TCOFLUSH:
      37        arg = FWRITE;
      38        break;
      39      case TCIOFLUSH:
      40        arg = FREAD | FWRITE;
      41        break;
      42      default:
      43        __set_errno (EINVAL);
      44        return -1;
      45      }
      46  
      47    return __ioctl (fd, TIOCFLUSH, (void *) &arg);
      48  }