Re: [Boost-users] [msm] extending msm::back::state_machine

Subject: Re: [Boost-users] [msm] extending msm::back::state_machine
From: Manuel Schiller (caligano_at_[hidden])
Date: 2014-09-08 00:17:43

Hi Christophe,

thanks for the reply.
The reason I want to extend the backend is that I need to maintain a
separate event queue (a job queue).
In reality, "test()" is a function template, so I cannot use virtual
functions.

If I implement this function template in the frontend, I need to
static_cast to the backend, which I try to avoid:

struct fsm_ : public boost::msm::front::state_machine_def<fsm_>
{

typedef msmb::state_machine<fsm_> BackMachine;

template <typename EventType>
void enqueue_job(const EventType& evt)
{
        job_queue.push(
                    std::bind(&BackMachine::template
process_event<EventType>, static_cast<BackMachine*>(this), evt)
                    );
}

// ...

};

Is there any third option?

Bye,
Manuel

2014-09-07 21:42 GMT+02:00 <christophe.j.henry_at_[hidden]>:

>   Hi,
>
> >
>  >When compiling the attached example, I get this error message
> *>error: ‘class boost::msm::back::state_machine<fsm_,
> boost::parameter::void_, boost::parameter::void_, boost::parameter::void_,
> boost::parameter::void_>’ has no member named ‘test’*
> >
> >
> >How can I "inject" extended_back_machine as the type being passed as
> "FSM" to the state?
> The argument passed to on_entry is not extended_back_machine because MSM
> does not know about it. You can either:
>
> - implement test() within the fsm_ front-end
> - provide a virtual, empty implemented test() within the front end and let
> the compiler find out itself about the overriden one: virtual void test(){}
>
> HTH,
> Christophe
>
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