Converting int to int* in python

Question

We are using SWIG to test C++ API with Python. One of the method in C++ expects int * as int fnClicTestIntPtr(int *) ; It just adds one at returns value. I am trying to call this method in Python and test the output. Can you please tell me how can i pass int* in Pyhton.

My interface file looks like this:

   %module ClicTest
   %{
   #include "ClicTest.h"

   %}
   %include <windows.i>
   %include "ClicTest.h"

Header file:

  #ifdef CLICTEST_EXPORTS
  #define CLICTEST_API __declspec(dllexport)
  #else
  #define CLICTEST_API __declspec(dllimport)
  #endif

 // This class is exported from the ClicTest.dll
 class CLICTEST_API CClicTest {
 public:
CClicTest(void);
// TODO: add your methods here.
  };

 extern CLICTEST_API int nClicTest;

 CLICTEST_API int fnClicTest(void);

 CLICTEST_API int fnClicTestInt(int);

 CLICTEST_API char* fnClicTestChar(char *);

 CLICTEST_API int fnClicTestIntPtr(int *);

 CLICTEST_API int fnClicTestVoidPtr(void *);

 CLICTEST_API char* fnClicTestCharPtr(char *);

 CLICTEST_API long fnClicTestLongPtr(long *);

I tried passing a number , also tried using ctypes.byref and ctypes.pointer methods. But nothing has been successfull.Like below

Py file:

 print(ClicTest.fnClicTestLongPtr(ctypes.pointer(num)))
 print(ClicTest.fnClicTestLongPtr(num))
 print(ClicTest.fnClicTestLongPtr(ctypes.byref(num)))

-

Error : TypeError: in method 'fnClicTestIntPtr', argument 1 of type 'int *

Answer 1

We had to include “cpointer.i” interface in the interface file (connecting C++ to Python using SWIG). Refer to http://www.swig.org/Doc2.0/Library.html#Library for more details