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/* Linux implementation of preadv2.
Copyright (C) 2017-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C 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.
The GNU C 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 the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sys/uio.h>
#include <sysdep-cancel.h>
#ifndef __OFF_T_MATCHES_OFF64_T
# if !defined (__NR_preadv2) && defined (__NR_pread64v2)
# define __NR_preadv2 __NR_pread64v2
# endif
ssize_t
preadv2 (int fd, const struct iovec *vector, int count, off_t offset,
int flags)
{
# ifdef __NR_preadv2
ssize_t result = SYSCALL_CANCEL (preadv2, fd, vector, count,
LO_HI_LONG (offset), flags);
if (result >= 0 || errno != ENOSYS)
return result;
# endif
/* Trying to emulate the preadv2 syscall flags is troublesome:
* We can not temporary change the file state of the O_DSYNC and O_SYNC
flags to emulate RWF_{D}SYNC (attempts to change the state of using
fcntl are silently ignored).
* IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
semantic not provided by any other flag (O_NONBLOCK for instance). */
if (flags != 0)
{
__set_errno (ENOTSUP);
return -1;
}
if (offset == -1)
return __readv (fd, vector, count);
else
return preadv (fd, vector, count, offset);
}
#endif
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