Question

I have a basic_iostream derived class like this:

class MyStream : public std::basic_iostream< char >, 
                 private boost::noncopyable
{
public:
    explicit MyStream( SomeUsefulData& data ) : 
        buffer_( data ),
        std::basic_iostream< char >( &buffer_ )
    {
    };

    ~MyStream()
    {
    };

private:
    /// internal stream buffer
   MyStreamBuffer< char > buffer_;
}; // class MyStream

When I create an instance of it, though, I get a DataAbort exception.

SomeUsefulData data;
MyStream stream( data );  // <- Data Abort

If, however I change MyStream to heap allocate the MyStreamBuffer, it works fine:

class MyStream : public std::basic_iostream< char >, 
                 private boost::noncopyable
{
public:
    explicit MyStream( SomeUsefulData& data ) : 
        std::basic_iostream< char >( new MyStreamBuffer< char >( data ) )
    {
    };

    ~MyStream()
    {
        delete rdbuf();
    };
}; // class MyStream

Is it wrong to use a class member to initialize a parent class?

Thanks,
PaulH

Answer 1

Direct base classes are always initialised first, no matter what order you put the initialisation statements in.
If you turn on more compiler warnings, you should get a warning about this.

Which means that yes, it is wrong to initialise a base class with a member, sorry!