Python os.fsync() Method


Python 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.


Following is the syntax for fsync() method −



Return Value

This method does not return any value.


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


import os, sys

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

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

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

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

# Close opened file
os.close( fd )

print "Closed the file successfully!!"

When we run above program, it produces following result −

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