如何使用 ctypes 查看 python 中的指针值变化

Question

I want to implement void function in C and in that function I will change pointer value, like this:

void func(int* k){ *k = 9; }

As you can see, here I am changing k value, let's say with 9. How can I write this function in python using ctypes so I can see what is the changed value is, in C.lets say following python code example

import ctypes
d = ctypes.CDLL(r'mydll.dll')
d.our_function.argtypes = (ctypes.POINTER(ctypes.c_int))

As you can see there is no return, so how can I see in my python call, that my value is changed? sorry for my bad English...

Answer 1

You need to allocate an int yourself in Python and pass its address, like this:

k = c_int()
d.our_function(byref(k))
print(k.value)