The Global Interpreter Lock, or GIL, is a mechanism used in the Python interpreter to synchronize the execution of threads for safety and prevents multiple native threads from executing Python bytecodes at once. This lock is necessary because CPython’s memory management (which is not thread-safe) is not designed to be multithreaded.
The GIL also protects Python objects from being simultaneously accessed by multiple threads and causing inconsistencies. Despite this, the GIL can be a limitation when trying to fully utilize the capabilities of multi-core processors in certain types of Python applications, particularly those which require heavy thread computation.
