Re: object copy with reference

Victor Bazarov <v.bazarov@comcast.invalid>
Sun, 25 Sep 2011 09:44:09 -0400
On 9/25/2011 7:43 AM, Philipp Kraus wrote:

I have a class method that is run in different threads:
myclass::mythreadmethod( mysuperclass& )

Is there any relationship between 'myclass' and 'mysuperclass'?

mysuperclass is a reference variable, that is used during the thread is

OK, nothing strange here so far.

Anyway the method should be myclass::mythreadmethod( mysuperclass ), so
each running thread has a own local copy of the object, but I can't
switch the parameter
because the method is derivated of another class.

So, the other class (from which your 'myclass' is derived) requires the
argument to be a reference to a non-const object. Seems OK. You can
implement your own


by overriding the 'mythreadmethod' this way:

    returntype myclass::mythreadmethod(mysuperclass& o)
       mysuperclass local_o(o);
       return this->mythreadmethod_impl(local_o);

(although, strictly speaking, the creation of local_o isn't necessary,
it's done here just for illustrating the fact of copying the 'o').

I need in the method a local (deep-copy) of my object. So I create a
clone method like
myclass::mythreadmethod( mysuperclass& pobj )
mysuperclass& lobj = p_obj.clone();

In this case I get the compiler error, that I try to set up a temporary

"Temporary assignment"? What's that?

And what error do you get?

The try to do it like
myclass::mythreadmethod( mysuperclass& pobj )
mysuperclass& lobj;

You cannot declare a local object of type reference without initializing
it. That ought to be flagged by the compiler as an error.

create the message l_obj isn't initializate.

Does anyone has some tips to create a working solution? The perfect
should be a deep-copy of the pobj reference

See above. It does depend, however, on how 'mysuperclass' is defined.

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