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/* lseek-uart.c. Implementation of the _lseek syscall for newlib with UART
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Copyright (C) 2004, Jacob Bower
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Copyright (C) 2010, Embecosm Limited <info@embecosm.com>
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Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
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This file is part of Newlib.
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The original work by Jacob Bower is provided as-is without any kind of
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warranty. Use it at your own risk!
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All subsequent work is bound by version 3 of the GPL as follows.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along
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with this program. If not, see <http:#www.gnu.org/licenses/>. */
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/* -------------------------------------------------------------------------- */
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/* This program is commented throughout in a fashion suitable for processing
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with Doxygen. */
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/* -------------------------------------------------------------------------- */
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#include <errno.h>
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#include <unistd.h>
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#undef errno
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extern int errno;
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/* -------------------------------------------------------------------------- */
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/*!Set a position in a file when using a UART.
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We only support stdin, stdout and stderr for which positioning is always to
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offset 0.
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Remember that this function is *not* reentrant, so no static state should
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be held.
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@param[in] file The fileno to lseek.
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@param[in] offset The desired offset.
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@param[in] whence Where to lseek from.
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@return 0, indicating the offset achieved. */
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/* -------------------------------------------------------------------------- */
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int
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_lseek (int file,
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int offset,
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int whence)
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{
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if ((STDIN_FILENO == file) ||
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(STDOUT_FILENO == file) ||
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(STDERR_FILENO == file))
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{
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return 0;
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}
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else
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{
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errno = EBADF;
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return (long) -1;
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}
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} /* _lseek () */
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