nuttx/drivers/serial/tcdrain.c

102 lines
3.5 KiB
C

/****************************************************************************
* drivers/serial/tcdrain.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Copyright (C) 2017 Sebastien Lorquet. All rights reserved.
* Author: Sebastien Lorquet <sebastien@lorquet.fr>
*
* 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 <termios.h>
#include <errno.h>
#include <nuttx/cancelpt.h>
#include <nuttx/serial/tioctl.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcdrain
*
* Description:
* Function for draining the output buffer of a terminal/serial device
*
* Input Parameters:
* fd - The 'fd' argument is an open file descriptor associated with a terminal.
*
* Returned Value:
* Upon successful completion, 0 is returned. Otherwise, -1 is returned and
* errno is set to indicate the error.
*
****************************************************************************/
int tcdrain(int fd)
{
int ret;
/* tcdrain is a cancellation point */
if (enter_cancellation_point())
{
#ifdef CONFIG_CANCELLATION_POINTS
/* If there is a pending cancellation, then do not perform
* the wait. Exit now with ECANCELED.
*/
set_errno(ECANCELED);
leave_cancellation_point();
return ERROR;
#endif
}
/* Perform the TCDRM IOCTL command. It is safe to use the file descriptor
* in this context because we are executing on the calling application's
* thread.
*
* NOTE: ioctl() will set the errno variable and return ERROR is any error
* occurs.
*/
ret = ioctl(fd, TCDRN, (unsigned long)0);
leave_cancellation_point();
return ret;
}