I have the following old c code. Now, I need to use Python to call old c function. I have the following code. May I know what is the Python equivalent for c[2] = 0;? Answer None and 0 both work:

Python interfacing with C library – How to have a null c pointer

Mark Tolonen

edited 11 Oct, 2022

Cheok Yan Cheng

asked 17 Feb, 2011

I have the following old c code.

const char *c[3];
c[0] = "ABC";
c[1] = "EFG";
c[2] = 0;
c_function(c);

Now, I need to use Python to call old c function. I have the following code.

c_names = (c_char_p * 3)()
c_names[0] = "ABC";
c_names[1] = "EFG";
// c[2] = 0??
libc = CDLL("c_library.dll")
libc.c_function(c_names)

May I know what is the Python equivalent for c[2] = 0;?

None and 0 both work:

>>> import ctypes
>>> x=ctypes.c_char_p(0)
>>> x
c_char_p(None)
>>> x=ctypes.c_char_p(None)
>>> x
c_char_p(None)