ctypes Writer¶

The ctypes writer generates Python source code that uses the ctypes standard library to define C type bindings. The output is a runnable Python module containing struct/union classes, enum constants, type aliases, callback types, and function prototype annotations.

Writer Class¶

CtypesWriter ¶

CtypesWriter(lib_name='_lib')

Writer that generates Python ctypes binding modules from headerkit IR.

Options¶

lib_name : str Variable name for the loaded library object. Defaults to "_lib". Controls the variable name used in function prototype annotations (e.g., _lib.func.argtypes = [...]).

Example¶

::

from headerkit.writers import get_writer

writer = get_writer("ctypes", lib_name="mylib")
source = writer.write(header)

# Or directly:
from headerkit.writers.ctypes import CtypesWriter
writer = CtypesWriter(lib_name="_lib")
source = writer.write(header)

write ¶

write(header)

Convert header IR to Python ctypes binding source code.

hash_comment_format ¶

hash_comment_format()

Return format string for wrapping TOML cache metadata in Python comments.

Convenience Function¶

header_to_ctypes ¶

header_to_ctypes(header, lib_name='_lib')

Convert all declarations in a Header to a Python ctypes module string.

Parameters:

Name	Type	Description	Default
`header`	`Header`	Parsed header IR from headerkit.	required
`lib_name`	`str`	Variable name for the loaded library object. Used in function prototype annotations (e.g., `_lib.func.argtypes = [...]`).	`'_lib'`

Returns:

Type	Description
`str`	A string of Python source code defining ctypes bindings.

Low-Level Functions¶

These functions are used internally by header_to_ctypes and can be useful when working with individual type expressions.

type_to_ctypes ¶

type_to_ctypes(t)

Convert a type expression to its ctypes string representation.

Handles special cases like const char * -> ctypes.c_char_p, void * -> ctypes.c_void_p, and pointer/array composition.

Example¶

from headerkit.backends import get_backend
from headerkit.writers import get_writer

backend = get_backend()
header = backend.parse("""
typedef struct {
    int x;
    int y;
} Point;

int distance(Point* a, Point* b);
""", "geometry.h")

writer = get_writer("ctypes", lib_name="_geometry")
print(writer.write(header))

Output:

"""ctypes bindings generated from geometry.h."""

import ctypes
import ctypes.util
import sys

# ============================================================
# Structures and Unions
# ============================================================

class Point(ctypes.Structure):
    _fields_ = [
        ("x", ctypes.c_int),
        ("y", ctypes.c_int),
    ]

# ============================================================
# Function Prototypes
# ============================================================

_geometry.distance.argtypes = [ctypes.POINTER(Point), ctypes.POINTER(Point)]
_geometry.distance.restype = ctypes.c_int