[python] How do I check if I'm running on Windows in Python?

I found the platform module but it says it returns 'Windows' and it's returning 'Microsoft' on my machine. I notice in another thread here on stackoverflow it returns 'Vista' sometimes.

So, the question is, how do implemement?

if isWindows():
  ...

In a forward compatible way? If I have to check for things like 'Vista' then it will break when the next version of windows comes out.

Note: The answers claiming this is a duplicate question do not actually answer the question isWindows. They answer the question "what platform". Since many flavors of windows exist none of them comprehensively describe how to get an answer of isWindows.

You should be able to rely on os.name.

import os
if os.name == 'nt':
    # ...

edit: Now I'd say the clearest way to do this is via the platform module, as per the other answer.

import platform
is_windows = any(platform.win32_ver())

or

import sys
is_windows = hasattr(sys, 'getwindowsversion')

Are you using platform.system?

 system()
        Returns the system/OS name, e.g. 'Linux', 'Windows' or 'Java'.

        An empty string is returned if the value cannot be determined.

If that isn't working, maybe try platform.win32_ver and if it doesn't raise an exception, you're on Windows; but I don't know if that's forward compatible to 64-bit, since it has 32 in the name.

win32_ver(release='', version='', csd='', ptype='')
        Get additional version information from the Windows Registry
        and return a tuple (version,csd,ptype) referring to version
        number, CSD level and OS type (multi/single
        processor).

But os.name is probably the way to go, as others have mentioned.

if sys.platform == 'win32':
#---------
if os.environ.get('OS','') == 'Windows_NT':
#---------
try: import win32api
#---------
# Emulation using _winreg (added in Python 2.0) and
# sys.getwindowsversion() (added in Python 2.3)
import _winreg
GetVersionEx = sys.getwindowsversion
#----------
def system():

    """ Returns the system/OS name, e.g. 'Linux', 'Windows' or 'Java'.    
        An empty string is returned if the value cannot be determined.   
    """
    return uname()[0]

in sys too:

import sys
# its win32, maybe there is win64 too?
is_windows = sys.platform.startswith('win')