Swig Friend Method Minimum Reproducible Example

testswig.cpp

#include "testswig.h"

ClassWithProtectedFriendMethod::ClassWithProtectedFriendMethod()
{
}

ClassWithProtectedFriendMethod::protectedFriendMethod()
{
  return -42.0;
}

ClassWithProtectedFriendMethod::publicMethod()
{
  return 42.0;
}

testswig.h

#ifndef SWIGEXAMPLE_H
#define SWIGEXAMPLE_H

/**
* \ingroup functionEncoder
*
* Encode any given function as a set of wavelet coefficients. 
* The father wavelet used here is the \b db4.
*/
class ClassWithProtectedFriendMethod
{
protected:
    friend double protectedFriendMethod();

public:
    /**
    * Constructor.
    */
    ClassWithProtectedFriendMethod();

    double publicMethod();
};

#endif

testswig.i

%module testswig

%{

#include "testswig.h"

%}


%include "testswig.h"