swig_python_wrapper_for_c_function_and_global_variable.py

1# --- example.c ---
2# /* 
3#  * This is the C code to be wrapped. 
4#  * In a real scenario, this would be in a separate file.
5#  */
6# double My_variable = 3.0;
7# int fact(int n) {
8#     if (n <= 1) return 1;
9#     else return n*fact(n-1);
10# }
11
12# --- example.i ---
13# /* This is the SWIG interface file */
14# %module example
15# %{
16# extern double My_variable;
17# extern int fact(int n);
18# %}
19# extern double My_variable;
20# extern int fact(int n);
21
22# --- setup.py ---
23# /* To build the module, you would typically use a setup.py file: */
24# from setuptools import setup, Extension
25# setup(name='example',
26#       ext_modules=[Extension('_example', ['example_wrap.c', 'example.c'])])
27
28# --- Python Usage Example ---
29import example
30
31# Access the C function
32result = example.fact(5)
33print(f"fact(5) = {result}")
34
35# Access the C global variable
36print(f"My_variable = {example.cvar.My_variable}")
37
38# Modify the C global variable
39example.cvar.My_variable = 5.0
40print(f"New My_variable = {example.cvar.My_variable}")