---
name: "lseek64"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/lseek64"
---

# lseek64(3)

reposition 64-bit read/write file offset

## NAME

lseek64 - reposition 64-bit read/write file offset

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#define _LARGEFILE64_SOURCE     /* See feature_test_macros(7) */
#include <sys/types.h>
#include <unistd.h>
```

**\[\[deprecated\]\] off64\_t lseek64(int** *fd***, off64\_t** *offset***, int** *whence***);**

## DESCRIPTION

This function is equivalent to [**lseek**(2)](/lseek/2.md) if one compiles with

```
#define _FILE_OFFSET_BITS 64
```

Use [**lseek**(2)](/lseek/2.md) instead.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **lseek64**() | Thread safety | MT-Safe |

## HISTORY

glibc 2.1.

**lseek64**() is one of the functions that was specified in the Large File Summit (LFS) specification that was completed in 1996. The purpose of the specification was to provide transitional support that allowed applications on 32-bit systems to access files whose size exceeds that which can be represented with a 32-bit *off\_t* type.

## SEE ALSO

[**\_llseek**(2)](/_llseek/2.md), [**lseek**(2)](/lseek/2.md)