llseek

(2)

reposition read/write file offset

System callsmanpages-dev 6.9.1-1

#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).

LIBRARY

Standard C library (libc, -lc)

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 64-bit signed type.

This system call exists on various 32-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.