Python os.close() Method

Python os.close() Method

Imran Alam Jul-27, 2022 Python Python OS
  1. Syntax of os.close():
  2. Example Codes: Create a File Descriptor and Close Using the os.close() Method
  3. Example Codes: Automatically Close the File Descriptor Using the os.close() Method and the with Statement
  4. Example Codes: Close Multiple File Descriptors Using the os.closerange() Method
  5. Example Codes: Possible Errors While Using the os.close() Method

The os.close() method is used to close a file descriptor. This method is a part of the OS module.

Syntax of os.close():

os.close(fd)

Parameter

fd This is the file descriptor to be closed.

Return

This method does not return any value.

Example Codes: Create a File Descriptor and Close Using the os.close() Method

In the following example, we will create a file descriptor and then close it using the os.close() method:

import os

# Create a file descriptor
fd = os.open("sample.txt", os.O_RDWR)

# Close the file descriptor
os.close(fd)

Example Codes: Automatically Close the File Descriptor Using the os.close() Method and the with Statement

In the following example, we will use the with statement to close the file descriptor automatically:

import os

# Open a file descriptor
with os.open("sample.txt", os.O_RDWR) as fd:

    # Perform file operations
    os.write(fd, "Hello, world!")
    os.lseek(fd, 0, os.SEEK_SET)
    print(os.read(fd, 100))

Example Codes: Close Multiple File Descriptors Using the os.closerange() Method

We can also close multiple file descriptors at once using the os.closerange() method:

import os

# Open two file descriptors
fd1 = os.open("sample1.txt", os.O_RDWR)
fd2 = os.open("sample2.txt", os.O_RDWR)

# Close both file descriptors
os.closerange(fd1, fd2)

Example Codes: Possible Errors While Using the os.close() Method

Some of the possible errors that can occur while using the os.close() method are:

  1. EBADF - This error occurs when the file descriptor is not valid.
  2. EINTR - This error occurs when the close operation is interrupted by a signal.

EBADF Error

In the following example, we will try to close a file descriptor that is not valid:

import os

# Create a file descriptor
fd = os.open("sample.txt", os.O_RDWR)

# Try to close an invalid file descriptor
os.close(fd + 1)

Output:

Traceback (most recent call last):
  File "sample.py", line 6, in <module>
    os.close(fd + 1)
OSError: [Errno 9] Bad file descriptor

EINTR Error

In the following example, we will try to close a file descriptor that is interrupted by a signal:

import os
import signal

# Create a file descriptor
fd = os.open("sample.txt", os.O_RDWR)

# Interrupt the close operation with a signal
os.kill(os.getpid(), signal.SIGINT)

# Try to close the file descriptor
os.close(fd)

Output:

Traceback (most recent call last):
  File "sample.py", line 8, in <module>
    os.close(fd)
OSError: [Errno 4] Interrupted system call

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