px4-firmware/apps/examples/ostest/dev_null.c

93 lines
3.1 KiB
C
Raw Normal View History

/****************************************************************************
* examples/ostest/dev_null.c
*
* Copyright (C) 2007, 2008 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 <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include "ostest.h"
/****************************************************************************
* Private Data
****************************************************************************/
#if CONFIG_NFILE_DESCRIPTORS > 0
static FAR char buffer[1024];
/****************************************************************************
* Public Functions
****************************************************************************/
int dev_null(void)
{
int nbytes;
int fd;
fd = open("/dev/null", O_RDWR);
if (fd < 0)
{
printf("dev_null: ERROR Failed to open /dev/null\n");
return -1;
}
nbytes = read(fd, buffer, 1024);
if (nbytes < 0)
{
printf("dev_null: ERROR Failed to read from /dev/null\n");
close(fd);
return -1;
}
printf("dev_null: Read %d bytes from /dev/null\n", nbytes);
nbytes = write(fd, buffer, 1024);
if (nbytes < 0)
{
printf("dev_null: ERROR Failed to write to /dev/null\n");
close(fd);
return -1;
}
printf("dev_null: Wrote %d bytes to /dev/null\n", nbytes);
close(fd);
return 0;
}
#endif /*CONFIG_NFILE_DESCRIPTORS */