Python os.lseek() Method

Overview

The os.lseek() method is used to set the current position of the file descriptor fd to pos, modified by the how parameter.

It is valid on Unix and Windows.

Syntax

The syntax for the lseek() method is as follows:

os.lseek(fd, pos, how)

Parameters

• fd -- The file descriptor.
• pos -- This is the position in the file relative to the given how parameter.
• how -- The reference position within the file. SEEK_SET or 0 sets the position relative to the beginning of the file; SEEK_CUR or 1 sets it relative to the current position; os.SEEK_END or 2 sets it relative to the end of the file.

Return Value

This method does not return a value.

Example

The following example demonstrates the use of the lseek() method:

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import os, sys

# Open file
fd = os.open("foo.txt", os.O_RDWR|os.O_CREAT)

# Write string
os.write(fd, "This is test")

# All fsync() method
os.fsync(fd)

# Read string from start
os.lseek(fd, 0, 0)
str = os.read(fd, 100)
print("Read String is : "), str

# Close file
os.close(fd)
print("File closed successfully!!")

Executing the above program produces the following output:

File closed successfully!!