What is the limitation of GIL in Python and how does it affect the execution of multithreaded programs?

GIL (Global Interpreter Lock) is a mechanism in CPython that ensures only one thread executes Python bytecode at any given time. This limitation is related to memory management and preventing race conditions within the interpreter.

Due to the GIL, multithreaded programs in Python cannot efficiently utilize multiple processor cores for CPU-intensive tasks, as threads do not run in parallel but are switched between. However, for I/O-bound tasks, multithreading is still useful, as threads can wait for I/O operations to complete, freeing the GIL for other threads.

To bypass the GIL, developers often use multiprocessing (multiprocessing), asynchronous programming, or Python implementations without GIL (e.g., Jython, IronPython).