Python Ctypes x64 OSError: exception: access violation reading 0x0000000000000008

Question

I'm trying to comunicate with an infrared camera, using python interface and ctypes to call sdk functions in dlls. There is one function in C++(only .h files are given)

int sdk_start_url(IRNETHANDLE p, char* ip);

where IRNETHANDLE is defined as void* type. I try to call that function using

IrCamCtrldll.sdk_start_url.argtypes = (c_void_p, c_char_p)

ret = IrCamCtrldll.sdk_start_url(handle, c_char_p(b'192.168.1.123'))

Error appears as:

OSError: exception: access violation reading 0x0000000000000008

As I have used handle in other similiar functions, errors should NOT appeard with that. So there is something wrong with the second parameter.

Thanks in advance!