Assigning member function to callback with boost::bind and boost::function

Question

I am trying to assign a member function as the callback to an API method, but it return the below error message, I am not sure how to resolve this.

cannot convert ‘boost::function<int(rcv_t_stct*, msg_t_stct*)>*’ to ‘rcv_cb {aka int (*)(rcv_t_stct*, msg_t_stct*)}’

callback signature:

typedef int (*rcv_cb)(rcv_t *rcv, msg_t *msg);

callback setter:

create(rcv_cb cb);

my member function:

int receiver::on_received(rcv_t *rcv, msg_t *msg)
{
    return 0;
}

attempted to assign to the setter:

boost::function<int (rcv_t *, msg_t *)> f2( boost::bind( &receiver::on_received, this, _1, _2) ); 
create(f2);

Solution:

I changed the receiver class to singleton, and used a static member function to wrap the non-static one.

int receiver::on_received(rcv_t *rcv, msg_t *msg)
{
    return receiver::instance().on_received_private(rcv, msg);
}

Is this the best solution it can be to resolve this issue?

Answer 1

A boost::function<> is not a free function, but a functor (type implementing operator() ). You cannot convert from boost::function<S> to a pointer to a function with the signature S . If it is within your control, you can change the callback setter to take a boost::function<> rather than a free function. If that is outside of your control, then you cannot use a non-static member function for the callback.