Re: C2664 on initializing auto_ptr with const patam in constructor

From:
David Wilkinson <no-reply@effisols.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 08 May 2008 08:09:55 -0400
Message-ID:
<#mpArRQsIHA.4788@TK2MSFTNGP03.phx.gbl>
David Wilkinson wrote:

Fabian wrote:

Hello,

I've got a class like this:

namespace Spimaging
{

class SPIMAGING_API StackOpZDivision: public IStackOperation
{
private:
const auto_ptr<Spimage> m_opDivisor;
public:
explicit StackOpZDivision(const Spimage* i_opDivisor);
...
};

StackOpZDivision::StackOpZDivision(const Spimage* i_opDivisor):
m_opDivisor(i_opDivisor) {}

}

When I try to compile it I get the message "error C2664:
'std::auto_ptr<_Ty>::auto_ptr(_Ty *) throw()' : cannot convert
parameter 1 from 'const Spimaging::Spimage *' to 'Spimaging::Spimage *'"

I'm just trying to initialize a const auto_ptr with a const value. Is
that impossible?


Fabian:

The auto_ptr constructor does not take a const pointer argument. The
const-ness of the auto_ptr will prevent you from calling non-const
methods of Spimage.


Fabian:

Oops, I forgot to tell you that when I tested this, I used auto_ptr<const Spimage>.

Why do you think you want the auto_ptr itself to be constant?

--
David Wilkinson
Visual C++ MVP

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