Re: [Boost-users] [msm] Injecting events to FSMs from different translation units

Subject: Re: [Boost-users] [msm] Injecting events to FSMs from different translation units
From: Juraj Ivanèiæ (juraj.ivancic_at_[hidden])
Date: 2013-05-14 04:29:13

On 13.5.2013. 23:27, samriti katoch wrote:
> Hi,
>
> I am using boost msm to design state machines for a relatively large
> project.
>
> The documentation online is pretty good and I was able to figure out
> most features by looking at the sample code (thanks!).
>
> My particular application  has multiple FSM instances active at any
> given time, and what I would like to do is to be able to generate events
> for a particular FSM instance from different translation units. But I'd
> like to keep the the compile time at a minimum.
>
> I found an answer from Christophe for a similar question sometime back
> here: http://stackoverflow.com/questions/10899641/boost-msm-class
>
> Since, I have multiple FSM instances it would not help to have a
> singleton class with the FSM shared_ptr.

There is no singleton in the proposed solution. The proposed solution 
merely hides MSM guts from public headers to reduce compile time (pimpl 
idiom). Nothing is stopping you from creating multiple instances of 
PublicClass.

I think shared_ptr is causing the confusion - it is merely an 
implementation detail, data it points to is not intended to be shared 
between different PublicClass objects. You could also have use a plain 
pointer (but then you need to consider copy semantics), or scoped_ptr 
(which would make this class non-copyable).