Passing Python function to Boost C++

Question

I\'m trying to learn about Boost functions. I want to pass a Python function to a C++ module wrapped using Boost Python. I followed the example given here and modified it to acc

Answer 1

After a lot of searching and some trial & error, I managed to modify my code so that it works. I had to create a wrapper struct for the Boost Python object, which included a operator() method, so that the wrapped object could then be cast as a Boost Function before being assigned to the op variable. Here's the modified code:

struct op_wrapper_t {

  op_wrapper_t( object callable ) : _callable( callable ) {}

  double operator()(double t) {
    return extract(_callable(t));
  }

  object _callable;
};

void setOperator(object obj) {
  op = boost::function( op_wrapper_t(obj) );
}

I followed a similar procedure as the one in this post. However, I still don't understand why no such wrapper/casting is needed for functions that return void.