Re: Dll-Export of Pimpl
Kasimir wrote:
Hi,
I use the pimpl-idiom with std::auto_ptr for RAII.
With the following Code I get a compiler-warning 4150 (deletion of
pointer to incomplete type) (I have already turned off #4251).
<code>
#pragma warning(disable:4251)
#include <memory>
#define EXPORT __declspec(dllexport)
class EXPORT X
{
std::auto_ptr<class Y> y_;
public:
X();
~X();
};
</code>
In the Assembler-Listing a lot of std::auto_ptr-functions are
generated (That is not the case, if you #undef the EXPORT-Macro). y_
is a private member, so any access is limited to X::member-functions -
no need to export any std::auto_ptr<Y>-function. X::~X() does the
'deletion' and it knows how, so then there is no 'incomplete type'. Is
this a bug of VC++2005?
No, it is undefined behaviour to declare an auto_ptr to an incomplete type.
Any ideas how to get rid of this warning without explicitly turning it
off?
Notwithstanding the above, you can workaround the issue for VC (it may
or may not work with other compilers) by following Doug's advice.
Alternatively, you could use a pimpl class that has specifically been
designed to work with incomplete types, such as boost::shared_ptr (see
www.boost.org).
Tom