7. C API and Extensions

The Python C API, reference ownership rules, creating extension modules, defining new types, the buffer protocol, capsules, stable ABI, limited API, embedding Python, and cross-language calls.

11 items

Chapter	Title
61	The Python C API
62	Reference Ownership Rules
63	Creating Extension Modules
64	Defining New Types
65	Buffer Protocol
66	Capsules
67	Stable ABI
68	Limited API
69	Embedding Python
70	Calling Python From C
71	Calling C From Python

Deep Reads › CPython Internals › 7. C API and Extensions ›

61. The Python C API

Public C API overview, Include/ header organization, and the stable vs. internal API distinction.

Deep Reads › CPython Internals › 7. C API and Extensions ›

62. Reference Ownership Rules

Borrowed vs. owned references, Py_XDECREF patterns, and common reference counting mistakes in extensions.

Deep Reads › CPython Internals › 7. C API and Extensions ›

63. Creating Extension Modules

PyModuleDef structure, PyModule_Create, multi-phase initialization (PEP 451), and module state.

Deep Reads › CPython Internals › 7. C API and Extensions ›

64. Defining New Types

PyTypeObject slot-by-slot walkthrough: tp_new, tp_init, tp_dealloc, tp_methods, tp_getset, and inheritance.

Deep Reads › CPython Internals › 7. C API and Extensions ›

65. Buffer Protocol

Py_buffer, PyBUF_* flags, PyObject_GetBuffer, and implementing the buffer protocol in a custom type.

Deep Reads › CPython Internals › 7. C API and Extensions ›

66. Capsules

PyCapsule_New, PyCapsule_GetPointer, and the pattern for passing opaque C pointers between extension modules.

Deep Reads › CPython Internals › 7. C API and Extensions ›

67. Stable ABI

The stable ABI symbol set, abi3 wheel tagging, and the constraints imposed by maintaining ABI compatibility.

Deep Reads › CPython Internals › 7. C API and Extensions ›

68. Limited API

Py_LIMITED_API version macros, symbols excluded from the limited API, and building abi3-compatible extensions.

Deep Reads › CPython Internals › 7. C API and Extensions ›

69. Embedding Python

Py_Initialize, PyConfig, embedding CPython in a host process, and managing interpreter lifetime.

Deep Reads › CPython Internals › 7. C API and Extensions ›

70. Calling Python From C

PyObject_Call, PyObject_CallNoArgs, argument tuple construction, and error checking after calling into Python.

Deep Reads › CPython Internals › 7. C API and Extensions ›

71. Calling C From Python

ctypes, cffi, and CFFI-based extension dispatch as the primary paths for calling C libraries from Python.