Python 3 - os.fsync() Method

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Description

The method fsync() forces write of file with file descriptor fd to disk. If you're starting with a Python file object f, first do f.flush(), and then do os.fsync(f.fileno()), to ensure that all internal buffers associated with f are written to disk.

Syntax

Following is the syntax for fsync() method −

os.fsync(fd)

Parameters

fd − This is the file descriptor for buffer sync is required.

Return Value

This method does not return any value.

Example

The following example shows the usage of fsync() method.

#!/usr/bin/python3
import os, sys

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

# Write one string
line = "this is test"
b = line.encode()
os.write(fd, b)

# Now you can use fsync() method.
# Infact here you would not be able to see its effect.
os.fsync(fd)

# Now read this file from the beginning
os.lseek(fd, 0, 0)
line = os.read(fd, 100)
b = line.decode()
print ("Read String is : ", b)

# Close opened file
os.close( fd )

print ("Closed the file successfully!!")

Result

When we run the above program, it produces the following result −

Read String is :  this is test
Closed the file successfully!!