C++ unique static id and class name with base class

Question

Having class TaskBase, each derived class of it must have name and unique id.

The TaskBase is something like below:

class TaskB         


        

Answer 1

class TaskBase
{
private:
    const void*  m_id;
    string m_name;

public:
    TaskBase(const void* m_id, string m_name): m_id(m_id), m_name(m_name)
    {
    }

    const void* id() const
    {
        return m_id;
    }

    string name() const
    {
         return m_name;
    };
};

template< typename DERIVED >
class TaskProxy: public TaskBase
{
public:   
    static const void* id()
    {
        //if you want to have for each object a unique id:
        //return reinterpret_cast(this);
        //just for each TaskProxy:
        return reinterpret_cast(typeid( DERIVED ).name());
    }

    static string name()
    {
        return typeid( DERIVED ).name();
    }

    TaskProxy(): TaskBase(id(), name()) {}
};

Usage:

class MyTask1 : public TaskProxy< MyTask1 >
{
};

class MyTask2 : public TaskProxy< MyTask2 >
{
};

...

MyTask1 myTask1;
TaskBase *baseA = &myTask1;
MyTask2 myTask2;
TaskBase *baseB = &myTask2;

cout << "Name: " << baseA->name() << "  Id:" << baseA->id() << endl;
cout << "Name: " << baseB->name() << "  Id:" << baseB->id() << endl;

Which outputs this (with gcc 4.6):

Name: 7MyTask1  Id:0x401228
Name: 7MyTask2  Id:0x4011c0