Subversion Repositories openrisc_2011-10-31

/* lseek-uart.c. Implementation of the _lseek syscall for newlib with UART

   Copyright (C) 2004, Jacob Bower

   Copyright (C) 2010, Embecosm Limited <info@embecosm.com>

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   This file is part of Newlib.

   The original work by Jacob Bower is provided as-is without any kind of

   warranty. Use it at your own risk!

   All subsequent work is bound by version 3 of the GPL as follows.

   This program 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.

   This program 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 this program.  If not, see <http:#www.gnu.org/licenses/>.             */

/* -------------------------------------------------------------------------- */

/* This program is commented throughout in a fashion suitable for processing

   with Doxygen.                                                              */

/* -------------------------------------------------------------------------- */

#include <errno.h>

#include <unistd.h>

#undef errno

extern int  errno;

/* -------------------------------------------------------------------------- */

/*!Set a position in a file when using a UART.

   We only support stdin, stdout and stderr for which positioning is always to

   offset 0.

   Remember that this function is *not* reentrant, so no static state should

   be held.

   @param[in] file    The fileno to lseek.

   @param[in] offset  The desired offset.

   @param[in] whence  Where to lseek from.

   @return  0, indicating the offset achieved.                                */

/* -------------------------------------------------------------------------- */

int

_lseek (int   file,

        int   offset,

        int   whence)

{

  if ((STDIN_FILENO  == file) ||

      (STDOUT_FILENO == file) ||

      (STDERR_FILENO == file))

    {

      return  0;

    }

  else

    {

      errno = EBADF;

      return (long) -1;

    }

}       /* _lseek () */