What is GIL and how can it be bypassed? Name three ways.

GIL (Global Interpreter Lock) is a mechanism in CPython that ensures that only one thread executes Python bytecode at a time. This limits parallelism in multi-threaded Python programs.

Three ways to bypass the GIL:

1. Multiprocessing: running multiple processes instead of threads. Each process has its own interpreter and memory, allowing the use of multiple CPU cores.

from multiprocessing import Pool

def f(x):
    return x*x

with Pool(4) as p:
    print(p.map(f, [1, 2, 3, 4]))

2. Using C/C++ extensions: libraries that release the GIL during heavy computations (e.g., NumPy, SciPy).

3. Asynchronous programming (asyncio): allows efficient use of waiting time for input/output without blocking, bypassing GIL restrictions at the thread level.

You can also use alternative Python implementations without GIL, such as Jython or IronPython, but they are less common.