Did you get the
ModuleNotFoundError: No Module Named 'fcntl'? This short tutorial will show you some useful ways that can help you resolve it.
The minimal occurrence of the error is when using Windows, for example, and you run
import fcntl or any derivative of the import statement such as
from fcntl import X but the
fcntl package is not available on the operating system you’re trying this (e.g., Windows).
>>> import fcntl Traceback (most recent call last): File "<pyshell#2>", line 1, in <module> import fcntl ModuleNotFoundError: No module named 'fcntl'
It doesn’t help to run
pip install fcntl either because there is no
fcntl package for Windows. And on Linux
fcntl is already part of the Python Standard Library!
PS C:\Users\xcent> pip install fcntl ERROR: Could not find a version that satisfies the requirement fcntl (from versions: none) ERROR: No matching distribution found for fcntl
The reason this doesn’t work on Windows is that “this module performs file control and I/O control on file descriptors. It is an interface to the
ioctl() Unix routines.” (docs)
And it doesn’t really make sense to find an
fcntl replacement for Windows (although, technically, there are some things you can do even though they are NOT very clean). Learn more here if you want to go down that route:
👉 Recommended Tutorial: Is There an
fcntl Replacement on Windows?
fcntl can only work on Unix-based systems!
On those Unix-based systems (e.g., Linux) where
fcntl is available however you don’t even need to install it because it’s part of the Python Standard Library as you can see on this screenshot from the official docs:
Let’s assume you are on a Unix-based system (e.g., Linux), and you have a working Python installation, so
fctnl should be available. Can the error still occur?
Yes, it can (although it’s very unlikely). By far the most frequent reason in tha case is that your Python installation is corrupted and you’d be well-advised to install or reinstall Python again.
🌍 Recommended Tutorial: How to Check ‘
fcntl‘ Package Version in Python?
While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.
To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.
His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.