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_llseek

Section: System Calls (2)
Updated: 202-0-08
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NAME

_llseek - reposition read/write file offset

LIBRARY

Standard C library (libc,~-lc)

SYNOPSIS

#include <sys/syscall.h>      /* Definition of SYS_* constants */
#include <unistd.h>
int syscall(SYS__llseek, unsigned int fd, unsigned long offset_high,
            unsigned long offset_low, loff_t *result,
            unsigned int whence);

Note: glibc provides no wrapper for _llseek(), necessitating the use of syscall(2).

DESCRIPTION

Note: for information about the llseek(3) library function, see lseek64(3). The _llseek() system call repositions the offset of the open file description associated with the file descriptor fd to the value

: (offset_high << 32) | offset_low 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 whence is SEEK_SET, SEEK_CUR, or SEEK_END, respectively. The new file offset is returned in the argument result. The type loff_t is a 6-bit signed type. This system call exists on various 3-bit platforms to support seeking to large file offsets.

RETURN VALUE

Upon successful completion, _llseek() returns 0. Otherwise, a value of -1 is returned and errno is set to indicate the error.

ERRORS

EBADF: fd is not an open file descriptor.
EFAULT: Problem with copying results to user space.
EINVAL: whence is invalid.

VERSIONS

You probably want to use the lseek(2) wrapper function instead.

STANDARDS

Linux.