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.\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl)
.\" Written 10 June 1995 by Andries Brouwer <aeb@cwi.nl>
.\" and Copyright (C) 2007, 2015, 2020, Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.\" Modified Thu Oct 31 15:16:23 1996 by Eric S. Raymond <esr@thyrsus.com>
.\"
.TH _llseek 2 2023-03-30 "Linux man-pages 6.05.01"
.SH NAME
_llseek \- reposition read/write file offset
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.BR "#include <sys/syscall.h>" " /* Definition of " SYS_* " constants */"
.B #include <unistd.h>
.PP
.BI "int syscall(SYS__llseek, unsigned int " fd ", unsigned long " offset_high ,
.BI " unsigned long " offset_low ", loff_t *" result ,
.BI " unsigned int " whence );
.fi
.PP
.IR Note :
glibc provides no wrapper for
.BR _llseek (),
necessitating the use of
.BR syscall (2).
.SH DESCRIPTION
Note: for information about the
.BR llseek (3)
library function, see
.BR lseek64 (3).
.PP
The
.BR _llseek ()
system call repositions the offset of the open file description associated
with the file descriptor
.I fd
to the value
.IP
(offset_high << 32) | offset_low
.PP
This new offset is a byte offset
relative to the beginning of the file, the current file offset,
or the end of the file, depending on whether
.I whence
is
.BR SEEK_SET ,
.BR SEEK_CUR ,
or
.BR SEEK_END ,
respectively.
.PP
The new file offset is returned in the argument
.IR result .
The type
.I loff_t
is a 64-bit signed type.
.PP
This system call exists on various 32-bit platforms to support
seeking to large file offsets.
.SH RETURN VALUE
Upon successful completion,
.BR _llseek ()
returns 0.
Otherwise, a value of \-1 is returned and
.I errno
is set to indicate the error.
.SH ERRORS
.TP
.B EBADF
.I fd
is not an open file descriptor.
.TP
.B EFAULT
Problem with copying results to user space.
.TP
.B EINVAL
.I whence
is invalid.
.SH VERSIONS
You probably want to use the
.BR lseek (2)
wrapper function instead.
.SH STANDARDS
Linux.
.SH SEE ALSO
.BR lseek (2),
.BR open (2),
.BR lseek64 (3)
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