Re: delete operator again
RenjithMohan wrote:
I have a seemingly simplistic question. I would like to know why the
array delete operator is not automatically invoked.
We all know that the compiler has to do some bookkeeping in order to
free the entire block of memory. There was a dispute in the standard
whether the size of the array must be specified in the [] syntax.
Finally it was decided that since it is error prone, it should be
avoided.
Too sad that nobody then came up with a standardised way to retrieve the
size of the array, thus forcing the user to store the size themselves with
the included overhead. Also, the current way to distinguish between delete
and delete[] is not much less error-prone... :(
If that is the case why cant the syntax be further simplified and
automatically invoke the correct form of the delete operator?.
Like if for example I have
class A;
A* pArr = new A[10];
and I say
delete pArr ; //automatically invoke operator delete [] ;
It should automatically invoke the array delete operator since the
nature of the type(whether it is an array or a simple pointer ) can be
determined from the declaration.
Ahem, no. pArr is a pointer and never an array, even if it points to an
array of As! However, that is just wrong terminology on your side.
I guess you mean that it should invoke the correct delete operation
regardless of whether it points to a single element or to an array. IOW,
these two expressions would become equivalent:
new A;
new A[1];
However, that would mean that even the single-element allocation would have
to allocate an array including the overhead of bookkeeping the size of it.
You could of course cook up more complicated scenarios like array of
polymorphic types etc.
You can't build arrays of baseclasses. The reason is that in order to index
into the array, you need to compute the address from the address of the
first element, but you can't do that if you don't know the size of each
element.
Uli
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