Question

Given the pseudo-code below, I want to catch the exception thrown by the sub-object a in class B, maintaining this object private in B. The catch clause as stated below doesn’t work because the object a is private in B. How can I catch this exception ?

Edit I have changed the pseudo-code to embed class A within class B.

class B
{
    class A
    {
        public:
        class Exception{};
        A() throw(Exception) { ... }  // A ctor throws an Exception class object
    } a;
    public:
    B() { ... }     //  B ctor
};

int main()
{
    try
    {
        B b;
    }
    catch( B::A::Exception& )
    {
        ...
    }

}

Answer 1

Add a typedef to the exception in the surrounding class.

class B
{
    class A
    {
        public:
        class Exception{};
        A() throw(Exception) {  }  // A ctor throws an Exception class object
    } a;

public:
  typedef A::Exception Except;
    B() {  }     //  B ctor
};

int main()
{
    try
    {
        B b;
    }
    catch( B::Except& )
    {

    }

}