Re: [Corelinux-develop] Smart pointers.

[Christophe Prud'h. <pru...@MI...>]

* Ian Crawford  [Thursday 06 September 2001 10:45 am ]  :
   > Now, I'm completely unfamiliar with CoreLinux++, so I might be out o=
f
   > line posting here.  I apologize in advance if this is the case.
Not at all, the point of this list is to share ideas on analysis/design/i=
mplementation

The problem with smart pointers  is that there are so many ways to do it =
and to use them.
IMHO depending on the type of application/usage, "different" policies sho=
uld/could be used
so when it comes to use smart pointers in multithreading codes, then the =
multithreaded version
would be used whereas the singlethreaded one would be used in general. Me=
mory management is also=20
a policy and can be done in several ways. Checking correctness/nonnullnes=
s is also a policy: whether you
want or not to check to validity of the pointee at any time.

In this respect the work of Andrei Alexandrescu(Modern C++ design publish=
ed by Addison Wesley ) is
very interesting and shows how smart pointers can be implemented using te=
mplates and policies.

Basically the smart pointer class look like this (excerpt from the book)


template
    <
        typename T,
        template <class> class OwnershipPolicy =3D RefCounted,
        class ConversionPolicy =3D DisallowConversion,
        template <class> class CheckingPolicy =3D AssertCheck,
        template <class> class StoragePolicy =3D DefaultSPStorage
    >
    class SmartPtr;

The various policies are orthogonal and can be changed easily. policies a=
re very small classes
which customized the behaviour of the SmartPtr.
I strongly suggest the reading of this book in general and the chapter on=
 smart pointer in particular.
I was waiting Frank to come back and discuss about this design.


see ya
C.
--=20
Christophe Prud'homme=20
OOA and OOD for Linux
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