I am working on a legacy C++ code with two libraries. Library1 is the main and Library2 uses classes from Library1 (so there are some #includes "HeaderFromLibrary1" in Library2).

Deep in the code of Library1, there is some work done and when something happens I need to set a boolean variable. Library2 has to be able to get this value and reset it.

All code is object-oriented, so there are no global variables nor C-functions, but only classes objects.

What would be the best way to be able to modify this boolean variable from these libraries?

What I did is, I created two new files in Library1: SharedData.cpp and SharedData.h.

SharedData.h

#ifndef SHARED_DATA_H_
#define SHARED_DATA_H_

namespace MyNameSpace
{
    /*
    * Get the Boolean and reset it to FALSE.
    */
    boolean GetAndResetBoolean(void);

    /*
    * Set the Boolean.
    */
    void SetBoolean(void);
}

#endif

SharedData.cpp

#include "util/SharedData.h"
#include "Mutex.h"

namespace MyNameSpace
{
    static Mutex mutexBoolean;
    static boolean myBoolean;

    /**
    * Method used to set the boolean.
    */
    void SetBoolean(void)
    {
        ScopedLock lock(mutexBoolean);
        myBoolean= TRUE;
    }

    /**
    * Method used to get and reset the Boolean.
    */
    boolean GetAndResetBoolean(void)
    {
        ScopedLock lock(mutexBoolean);
        boolean currentBoolean = myBoolean;
        myBoolean = FALSE;
        return currentBoolean;
    }
}

So I include the SharedData.h in the file I need to set the boolean (Library1) and also in the file I need to get the value and reset it.

I do not like that I have to create 2 "global" variables. I would prefer to store the boolean in an object, but the lifetime of the object that sets the boolean is not very long. And I do not want to include any HeaderFromLibrary2.h in Library1 because Library2 uses Library1 and not the other way around.

Do you have any recommendation?

Thank you in advance.

I am working on a legacy C++ code with two libraries. Library1 is the main and Library2 uses classes from Library1 (so there are some #includes "HeaderFromLibrary1" in Library2).

Deep in the code of Library1, there is some work done and when something happens I need to set a boolean variable. Library2 has to be able to get this value and reset it.

All code is object-oriented, so there are no global variables nor C-functions, but only classes objects.

What would be the best way to be able to modify this boolean variable from these libraries?

What I did is, I created two new files in Library1: SharedData.cpp and SharedData.h.

SharedData.h

#ifndef SHARED_DATA_H_
#define SHARED_DATA_H_

namespace MyNameSpace
{
    /*
    * Get the Boolean and reset it to FALSE.
    */
    boolean GetAndResetBoolean(void);

    /*
    * Set the Boolean.
    */
    void SetBoolean(void);
}

#endif

SharedData.cpp

#include "util/SharedData.h"
#include "Mutex.h"

namespace MyNameSpace
{
    static Mutex mutexBoolean;
    static boolean myBoolean;

    /**
    * Method used to set the boolean.
    */
    void SetBoolean(void)
    {
        ScopedLock lock(mutexBoolean);
        myBoolean= TRUE;
    }

    /**
    * Method used to get and reset the Boolean.
    */
    boolean GetAndResetBoolean(void)
    {
        ScopedLock lock(mutexBoolean);
        boolean currentBoolean = myBoolean;
        myBoolean = FALSE;
        return currentBoolean;
    }
}

So I include the SharedData.h in the file I need to set the boolean (Library1) and also in the file I need to get the value and reset it.

I do not like that I have to create 2 "global" variables. I would prefer to store the boolean in an object, but the lifetime of the object that sets the boolean is not very long. And I do not want to include any HeaderFromLibrary2.h in Library1 because Library2 uses Library1 and not the other way around.

Do you have any recommendation?