Python C Library

How many ways Python can interact with C libraries?

Two. There are two different modes totally.

1. ctypes to load any dynamic library from a C libraries
2. import module to import a dynamic library written using the Python C API

Let's clarify the terminology a bit:

1. ctypes to Load Dynamic Libraries (including any C library):

• ctypes is a foreign function interface (FFI) library in Python that allows you to call functions from dynamic/shared libraries written in languages like C.
• It can be used to load and call functions from C libraries (or any dynamic/shared libraries), and it's a more manual, low-level approach to interfacing with C code.
• Example with ctypes:

2. import module for Dynamic Libraries written in Python C API:
   • If a C library is written using the Python C API and compiled as a Python extension module (.pyd on Windows or .so on Unix-like systems), you can use the import statement to import and use it in Python.
   • This Pythonic approach typically provides a more seamless integration as it allows the C code to be treated as a native Python module.
   • Example with import module:

What's the file's name that Python look for when using import module to import C API libraries?

Python will look for a shared library with a suitable name, as determined by the platform conventions. The shared library could be named something like libexample.so on Unix-like systems or example.dll on Windows. The PyInit_example function initializes the module.

Python int object

Python uses a variable-size integer representation,

• Overhead size: 24 bytes, including Python header object
• Data size: 4 or 8 bytes, storing smaller int using 4 bytes and bigger int using 8 bytes.

>>> sys.getsizeof(0x560f7ab1e1c0)
32
>>> sys.getsizeof(0xc0)
28

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