How to check if your Python interpreter is running in 64-bit mode

Check if your Python interpreter is 64 bit from a Python program

To check if your Python interpreter is running in 64-bit mode, you can use the struct module to check the size of the long type.

In 64-bit mode, the long type is 64 bits, while in 32-bit mode it is only 32 bits. Here is an example of how to do this:

import struct

if struct.calcsize("P") * 8 == 64:
  print("Running in 64-bit mode.")

else:
  print("Not running in 64-bit mode.")

In this code, struct.calcsize("P") returns the size of a long type in bytes.

Since there are 8 bits in a byte, we multiply this value by 8 to get the total number of bits.

Then we compare this value to 64 to determine whether the Python interpreter is running in 64-bit mode or not.

Note that this method only works if you are running Python 2.

In Python 3, the long type has been removed, so this method will not work.

To check the bitness of a Python 3 interpreter, you can use the sys.maxsize attribute instead.

In 64-bit mode, sys.maxsize will be larger than 2147483647, which is the largest possible value for a 32-bit signed integer.

Here is an example of how to do this:

import sys

if sys.maxsize > 2147483647:
  print("Running in 64-bit mode.")

else:
  print("Not running in 64-bit mode.")