Llseek (2) Linux Manual Page

_llseek – reposition read/write file offset

Synopsis

#include <sys/types.h>

#include <unistd.h>

int _llseek(unsigned int fd, unsigned long offset_high,

 unsigned long offset_low, loff_t *result,

 unsigned int whence);

Note: There is no glibc wrapper for this system call; see NOTES.

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.

Conforming To

This function is Linux-specific, and should not be used in programs intended to be portable.

Notes

Glibc does not provide a wrapper for this system call. To invoke it directly, use syscall(2). However, you probably want to use the lseek(2) wrapper function instead.

Colophon

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llseek (2) Linux Manual Page