Re: Making a smart pointer which works with incomplete types

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Sun, 07 Sep 2008 20:47:42 +0200

Message-ID:

<k6idnc30B7BSvFnVnZ2dnUVZ_vadnZ2d@posted.comnet>

* Juha Nieminen:

Alf P. Steinbach wrote:

<code file="x.cpp">
#include "sp.h"

class X;
X* newX();
void deleteX( X* );

int main()
{
SmartPtr<X, deleteX> p( newX() );
}
</code>

Here you require a "deleteX" function to be implemented by the user
alongside the X class,

No.

and you require this "deleteX" function to be
given as template parameter to the smart pointer.

No. Well, yes, for this example code. But that's how example code goes, it sort
of needs to be concrete if it is to be any good to those who don't understand.

Of course that works like that, but it's burdensome for the user to
have to do that for every single type he uses with the smart pointer.
The smart pointer ought to create such a function automatically to ease
the user's task, which is the whole point.

If the smart pointer can do that then AFAICS you're content to assume a trivial
destructor for the incomplete type, in which case you don't need any special
smart pointer type -- any will do.

Cheers & hth.,

- Alf

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