[Help-gsl] gsl_multifit_function_fdf callbacks in C++

[Pedro Figueiredo Santana]

Hi!

I'm using 'gsl_multifit_function_fdf' for a nonlinear minimisation
problem in C++. I would like to have the callback functions as members
of the class as shown below:  

int MyClass::callback_df{
  ...
}

void MyClass::method1{
  ...
  gsl_multifit_function_fdf f;
  f.df = &MyClass::callback_df;
  ...
}

However, the g++ compiler says that it is not possible to convert the
method into the required callback type. Does anyone knows the best way
to do this? I've also tried to make the callback method static and
didn't help that much ...

Thanks,
Pedro Santana