This section provides a comprehensive guide to the C API for Python, which allows you to interact with Python objects and modules from C code.

Overview

The Python C API is a set of functions and data types that allow you to write C extensions for Python. It is used to create modules that can be imported into Python scripts, and to embed Python in C applications.

Getting Started

Before you start using the C API, you need to have a basic understanding of Python and C programming. It is also recommended to have a good understanding of the Python C API documentation.

For more information on getting started with Python and C, please visit our Python C API Tutorial.

Key Concepts

Here are some key concepts you should be familiar with before diving into the C API:

  • Objects: Everything in Python is an object, and the C API allows you to create, manipulate, and access these objects.
  • Types: Python objects are instances of types, and the C API provides functions to create and manage types.
  • Modules: Modules are collections of Python objects and functions, and the C API allows you to create and import modules.

Functions and Data Types

The C API provides a wide range of functions and data types to interact with Python objects and modules. Here are some of the most commonly used functions and data types:

  • PyObject: The base type for all Python objects.
  • PyTypeObject: The base type for all Python types.
  • PyModule_Create: Function to create a new module.
  • PyObject_New: Function to create a new Python object.

For a complete list of functions and data types, please refer to the Python C API Reference.

Example

Here is a simple example of a C extension module that prints "Hello, World!" when imported:

#include <Python.h>

static PyObject* hello(PyObject* self, PyObject* args) {
    printf("Hello, World!\n");
    Py_RETURN_NONE;
}

static PyMethodDef MyMethods[] = {
    {"hello", hello, METH_VARARGS, "Print 'Hello, World!'"},
    {NULL, NULL, 0, NULL}
};

static struct PyModuleDef mymodule = {
    PyModuleDef_HEAD_INIT,
    "mymodule",
    NULL,
    -1,
    MyMethods
};

PyMODINIT_FUNC PyInit_mymodule(void) {
    return PyModule_Create(&mymodule);
}

To compile and install this module, you would use the following commands:

gcc -shared -fPIC -I/usr/include/python3.x -o mymodule.so mymodule.c
python3 -m pip install mymodule

For more information on creating C extensions, please visit our C Extension Development Guide.

Conclusion

The Python C API is a powerful tool for extending Python with C code. By using the C API, you can create efficient and high-performance modules that can be used in Python scripts and applications.

For further reading, please check out our Python C API Documentation.

Python C API