fcntl substitute on Windows

The fcntl module is just used for locking the pinning file, so assuming you don't try multiple access, this can be an acceptable workaround. Place this module in your sys.path, and it should just work as the official fcntl module.

Try using this module (source) for development/testing purposes only in windows.

def fcntl(fd, op, arg=0):
    return 0
        
def ioctl(fd, op, arg=0, mutable_flag=True):
    if mutable_flag:
        return 0
    else:
        return ""
    
def flock(fd, op):
    return
        
def lockf(fd, operation, length=0, start=0, whence=0):
    return

Of course, then you need to place the fcntl.py module in your site-packages directory for the Python interpreter that you want to use. For example, %LOCALAPPDATA%\Programs\Python\Python310\lib\site-packages\fcntl\. This is where my site-packages live. Check Tutorialspoint to find where yours is located.


The substitute of fcntl on windows are win32api calls. The usage is completely different. It is not some switch you can just flip.

In other words, porting a fcntl-heavy-user module to windows is not trivial. It requires you to analyze what exactly each fcntl call does and then find the equivalent win32api code, if any.

There's also the possibility that some code using fcntl has no windows equivalent, which would require you to change the module api and maybe the structure/paradigm of the program using the module you're porting.

If you provide more details about the fcntl calls people can find windows equivalents.