How to use restricted Code through SWIG

Question

I have a code as mentioned following ..

File : a.h

#include <stdio.h>

#ifdef ALLOW
int check(int n);
#endif 

SWIG: test.i

%module test
%{
  #include "a.h"
%}

%include "a.h"

CMD: swig -python test.i

this is generating a _test.so , when i am importing this library to python this is not displaying check function defined.

In Make I could have used -D option, say gcc -DALLOW a.c.

How can I achieve the same using SWIG

Answer 1

As easy as it looks - swig -DALLOW -python test.i.

Answer 2

You can define preprocessor macros within the SWIG interface itself (i.e. inside the .i file).

So in your case you might want to do:

%module test
%{
  #include "a.h"
%}

#define ALLOW
%include "a.h"

That's enough to make SWIG itself "see inside" the #ifdef, but if you want to have ALLOW defined within the generated warpper code as well you'd want to add:

%module test
%{
  #define ALLOW
  #include "a.h"
%}

#define ALLOW    
%include "a.h"

because the contents of the %{ ... %} are passed straight through to that generated code whereas the plain #define only influences how SWIG itself sees the file.