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50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/*
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* pread function
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*
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* Copyright 1996 Alexandre Julliard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "config.h"
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#include "wine/port.h"
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#include <errno.h>
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#include <stdio.h>
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif
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/* FIXME: this is not thread-safe */
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#ifndef HAVE_PREAD
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ssize_t pread( int fd, void *buf, size_t count, off_t offset )
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{
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ssize_t ret;
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off_t old_pos;
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if ((old_pos = lseek( fd, 0, SEEK_CUR )) == -1) return -1;
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if (lseek( fd, offset, SEEK_SET ) == -1) return -1;
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if ((ret = read( fd, buf, count )) == -1)
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{
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int err = errno; /* save errno */
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lseek( fd, old_pos, SEEK_SET );
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errno = err;
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return -1;
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}
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if (lseek( fd, old_pos, SEEK_SET ) == -1) return -1;
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return ret;
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}
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#endif /* HAVE_PREAD */
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