Re: virtual fn, destructor
On Dec 13, 11:48 am, peter koch <peter.koch.lar...@gmail.com> wrote:
On 13 Dec., 09:01, Martin Drautzburg <Martin.Drautzb...@web.de> wrote:
SG wrote:
It's only necessary if you intend to delete an object of a
derived type through a pointer to the base class. If you
DON'T need this you can make the dtor PROTECTED and
non-virtual in the base class.
Sorry if this is a silly question, but can't I simply make
*all* destuctors virtual as a rule? What would I lose?
I believe that it is a good rule to have a virtual destructor
in all base-classes that have any virtual function. You can
then remove the virtual destructor in the cases where it does
not matter and performance tells you not to.
Presumably, if a class has virtual functions, it is designed for
inheritance. So either the destructor should be virtual, or it
should not be public. (I've encountered more than one case
where it was necessary to impose pre-conditions on delete. To
do this, you declare the destructor protected, and require
client code to call a member function---possibly static, but not
necessarily so---which verifies the pre-conditions before
calling delete.)
In cases where no virtual functions are defined, it would be
silly to introduce a virtual destructor "just in case".
Certainly.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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