ctypes

ctypes is the Python standard library's bridge to C. It loads a shared library at runtime (a .so, .dll, or .dylib), looks up functions inside it, and lets the caller invoke them as if they were Python functions. No compilation, no build system, no separate language. The trade-off is working close to the metal: every type has to be declared by hand, memory ownership is the caller's problem, and mistakes crash the interpreter instead of raising Python exceptions. This lesson covers how to use ctypes correctly, the common pitfalls, and how it compares to its modern alternative, cffi.