wait-for-input.c

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/*

Copyright (C) 2016-2017 John W. Eaton

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave 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 General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

// select may be provided by gnulib.  We don't include gnulib headers
// directly in Octave's C++ source files to avoid problems that may be
// caused by the way that gnulib overrides standard library functions.

// We don't need select directly, we just need to use it to wait for
// input on an open file descriptor.

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <sys/select.h>

#include "wait-for-input.h"

int
octave_wait_for_input (int fid)
{
  int retval = -1;

#if defined (HAVE_SELECT)
  if (fid >= 0)
    {
      fd_set set;

      FD_ZERO (&set);
      FD_SET (fid, &set);

      retval = select (FD_SETSIZE, &set, 0, 0, 0);
    }
#else
  retval = 1;
#endif

  return retval;
}