/****************************************************************************
 * libc/stdlib/lib_unlockpt.c
 *
 *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/ioctl.h>
#include <stdlib.h>

#ifdef CONFIG_PSEUDOTERM

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: unlockpt
 *
 * Description:
 *   The unlockpt() function unlocks the slave pseudoterminal device
 *   corresponding to the master pseudoterminal referred to by fd. 
 *   unlockpt() must be called before opening the slave side of a
 *   pseudoterminal. 
 *
 * Returned Values:
 *   When successful, unlockpt() returns 0. Otherwise, it returns -1 and
 *   sets errno appropriately.
 *
 *     EBADF - The fd argument is not a file descriptor open for writing. 
 *     EINVAL - The fd argument is not associated with a master
 *       pseudoterminal
 *
 ****************************************************************************/

int unlockpt(int fd)
{
  return ioctl(fd, TIOCSPTLCK, 0);
}

#endif /* CONFIG_PSEUDOTERM */