struct TChangeBlock
{
    TChangeBlock( TBase & base ):
        base( &base),
        previousState( base.isChangeBlocked() )
    {
        base.setChangeBlock( true );
    }

    ~TChangeBlock()
    {
        base->setChangeBlock( previousState );
    }

private:
    TChangeBlock( const TChangeBlock & );
    TChangeBlock & operator = ( const TChangeBlock & );

    TBase * base;
    bool previousState;
};





class TBase(...)
{
...
public:
    void setChangeBlock(bool block )
{
...
}
...
}