How serialize a boost::function to send it in a message_queue

Question

I am actually trying to serialize a boost::function using boost::serialize because I want to share it in a boost::interprocess::message_queue. I only see one way to do that, it is to use the non-intrusive version of boost::serialize.

namespace boost {   
 namespace serialization {
       template<class Archive>   
           void serialize(Archive & ar, boost::function<void()> & fct, const unsigned int version) 
       {
     ar & fct.args;
     ar & fct.arity;
     ar & fct.vtable;
     ar & fct.functor;
       }       
  }
}

I will also need to serialize vtable and functor, I didn't try it, I am not sure it is working.

So is there any way to serialize a boost::function in a proper way?

Thank you.

Answer 1

It's not going to be possible immediately.

There are 2 problems I can think of:

• pass the identity of the function
• pass the context of the function (for example, if created using bind or with a lambda)

Neither is trivial, and neither can be done without instrumenting the code (think reflection / introspection).

What you want here is the Command pattern, and a way to serialize those commands.

This requires that both processes are built on top of a common set of commands (a common library seems like a good idea) and that you implement serialization and deserialization for your commands.

For deserialization, you will want to look-up the Virtual Constructor Idiom.

Answer 2

I don't think there is any way to do it. To be able to serialize a function you would need to be able to serialize its binary code. But that is not possible as the code is at least platform dependent.

You may however make a function table and serialize index of a function in that table. In the deserializer you would need to construct that very same table and use the serialized index to get the real function from the table.