newlib-cygwin/newlib/libc/sys/rdos/lseek.c

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/*#######################################################################
# RDOS operating system
# Copyright (C) 1988-2006, Leif Ekblad
#
# This library is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# This library 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# The author of this program may be contacted at leif@rdos.net
#
# lseek.c
# lseek function implementation
#
##########################################################################*/
#include "config.h"
#include <_ansi.h>
#include <_syslist.h>
#include <unistd.h>
#include <errno.h>
#include <rdos.h>
off_t lseek(int file, off_t pos, int whence)
{
off_t temp;
switch (whence)
{
case SEEK_CUR:
temp = RdosGetFilePos(file);
temp += pos;
RdosSetFilePos(file, temp);
return temp;
case SEEK_SET:
RdosSetFilePos(file, pos);
return pos;
case SEEK_END:
temp = RdosGetFilePos(file);
temp += pos;
RdosSetFilePos(file, temp);
return temp;
default:
errno = EINVAL;
return - 1;
}
}