Re: [Boost-users] Question on Boost::statechart library orthogonalregions

From: Andreas Huber (ahd6974-spamboostorgtrap_at_[hidden])
Date: 2007-04-27 13:57:56

Serena Fritsch wrote:
>> Hi All,
>> Apologies if there are multiple psoting of this message.
>> I want to use the boost::statechart library. However i encountered a
>> small problem with using the orthogonal regions. In the statechart
>> tutorial, every class declaration is put into one file, however i
>> would like to put each class declaration into separate files.
[code & error snipped]

The ultimate problem lies in in Main.cpp (received by private email):

<original_code>
#include "Machine.h"
#include "C.h"
#include <iostream>
namespace sc = boost::statechart;
int main(){
 Machine machine;
 machine.initiate();
 machine.displayStateConfiguration(machine);
 return 0;
}
</original_code>

At the point of initiate() only one part of the initial state 
configuration is known (C and A). B is missing (which MSVC duly reports 
with an appropriate error message). Adding the following include to 
Main.cpp solves the problem:

#include "B.h"

For more information please see:

<http://www.boost-consulting.com/boost/libs/statechart/doc/faq.html#HideInnerWorkings>

This item says that the *initial state* must be known at the point of 
calling initiate() but it should more correctly say that the *initial 
state configuration* must be known at the point where initiate is 
called. That is, in addition to the state passed as InitialState to 
state_machine, all its direct and indirect inner states must also be 
known. There are ways to enhance encapsulation by means of 
custom_reactions (which probably need to be triggered by posting 
internal events in your case), please see:

<http://www.boost-consulting.com/boost/libs/statechart/doc/tutorial.html#SpreadingAStateMachineOverMultipleTranslationUnits>

HTH,

-- 
Andreas Huber
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