Table of Contents
Python's ctypes
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Overview
ctypes is a foreign function library for the Python programming language. It provides C-compatible data types and allows calling functions in DLLs or shared libraries. It can be used to wrap these libraries in pure Python.
Key Features
- **C-Compatible Data Types:** ctypes provides a set of C-compatible data types, including integers, floating-point numbers, pointers, arrays, and structures. This allows Python to interact with C libraries in a natural way.
- **Function Calling:** ctypes allows calling functions in DLLs or shared libraries, passing arguments and receiving return values. This makes it possible to access functionality that is not available in pure Python.
- **Library Wrapping:** ctypes can be used to wrap C libraries in pure Python, providing a Pythonic interface to the library's functionality. This makes the library easier to use and integrate with other Python code.
- **Error Handling:** ctypes provides mechanisms for handling errors that occur during function calls, such as invalid arguments or exceptions raised in the C code.
- **Platform Independence:** ctypes is designed to be platform-independent, allowing the same Python code to work on different operating systems.
Resources
- **Official Documentation:** s://docs.python.org/3/library/ctypes.html(https://docs.python.org/3/library/ctypes.html)
Code Example
```python import ctypes
- Load the C library
libc = ctypes.CDLL(“libc.so.6”)
- Define the argument and return types of the C function
libc.printf.argtypes = [ctypes.c_char_p] libc.printf.restype = ctypes.c_int
- Call the C function
libc.printf(b“Hello, world!\n”) ```
In this example, `ctypes` is used to load the C standard library (`libc.so.6`) and call the `printf` function. The `argtypes` and `restype` attributes are used to specify the argument and return types of the `printf` function, respectively. The `b“Hello, world!\n”` argument is a bytes object that represents the string to be printed.