default arguments in copy constructor
 

If I add default arguments to the end of my copy constructor, is it still considered a copy constructor? E.g. will it still be used in the places where a copy constructor would normally be used (or automatically generated).

I can verify that it works on one compiler (g++). That is, this does output the "copy ctor" message 3 times:

#include <iostream>



class Context

{

  // real thing actually has some methods

};



class A

{

  private:

    Context & m_context;



  public:

    A ( Context * context )

      :m_context ( MATT_DEREF ( context ) )

    {

      // probably do something with context here..

    }



    A ( const A & a, Context * new_context = 0 )

      :m_context ( new_context ? *new_context : a.m_context )

    {

      std::cout << "copy ctor\n";

      // probably do something with context here..

    }

};



void test ( A a )

{ return; }



int main ( void )

{

  Context c1, c2;

  A a1 ( &c1 );

  // implictly copying by passing as value

  test ( a1 );

  // explicitly copying in the same context

  A a2 ( a1 );

  // copying to a new context

  A a3 ( a1, &c2 );

  return EXIT_SUCCESS;

}

But, will this always work O.K.? are there any caveats/pitfalls etc?

Other alternatives considered:

- I can't have the generated copy ctor used, for various reasons (e.g. other pointers/reference members shouldn't be shallow copied ).
- I don't want to pass the pointer to "context" in later, because that makes other areas unpleasant. E.g. I need to use "context" in the constructor, and it's not meant to be trivially reseatable.
- I do want the rest of the copy constructors features (i.e. being able to initialize the object & its bases in order).
- I'd rather not have to write 3 constructors for every class like this.

Re: default arguments in copy constructor
 

The C++ Standard:
Other alternatives of... what?...

Re: default arguments in copy constructor
 

Ok, thanks.

Other alternatives meaning, the list I put of things that I could have done to avoid having to do this.