Swig - wrapping C struct

Question

Hello everyone, I am trying to write Python wrap for C code which uses struct.

modules.c:

struct foo
{
    int a;
};

struct foo bar;

modulues.i

%module nepal
%{
    struct foo
    {
        int a;
    }
%}

extern struct foo bar;

But during compiling I am given error:

In function ‘Swig_var_bar_set’: error: ‘bar’ undeclared (first use in this function)

Could you be so kind to help me how to correctly define export struct variable ?

Answer 1

Try this:

%module nepal
%{
    struct foo
    {
        int a;
    };

    extern struct foo bar;
%}

struct foo
{
    int a;
};

extern struct foo bar;

The code in %{ %} is inserted in the wrapper, and the code below it is parsed to create the wrapper. It's easier to put this all in a header file so it is not so repetitive:

modules.h

struct foo
{
    int a;
};

extern struct foo bar;

modules.c

#include "modules.h"
struct foo bar;

modules.i

%module nepal
%{
    #include "modules.h"
%}

%include "modules.h"