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Defining a Template for Managing Ownership of Interfaces

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The following code segment defines a template to aid in the management of interface ownership. The sample uses this template with the ICommand, ICommandTree, IRowset, IAccessor, and other interfaces.

template<class T> class XInterface
{
public:
    XInterface( T * p = 0 ) : _p( p ) {}
    ~XInterface() { if ( 0 != _p ) _p->Release(); }
    T * operator->() { return _p; }
    T * GetPointer() const { return _p; }
    IUnknown ** GetIUPointer() { return (IUnknown **) &amp;_p; }
    T ** GetPPointer() { return &amp;_p; }
    void ** GetQIPointer() { return (void **) &amp;_p; }
    T * Acquire() { T * p = _p; _p = 0; return p; }
    BOOL IsNull() { return ( 0 == _p ); }

private:
    T * _p;
};