cffi_callback.py

#!/usr/bin/python3
from cffi import FFI


f = FFI()

@f.callback("int(int)")
def pytest(a):
    return a*a

f.cdef("""
    void test(void);
    int (*pytest)(int);
""")

l = f.verify('''
    #include <stdio.h>

    static int (*pytest)(int);

    void test(){
        printf("Alice ma %d lalek.\\n", pytest(3));
    }

''')
l.pytest = pytest
l.test()