Working of the delete [ ] operator

[Megha Vishwanath]

Hi,

I'd like to know how heap aggregates created with a "new" operator at
non-contiguous memory locations get deallocated using the "delete []"
operator in VC++.

A garbage collectors in Java deallocate on the basis of a record
maintained during the "new" allocation.

Do we use something like a garbage collector to maintain arecord of
the heap memory start indexes.

Please enlighten me.

Thanks,

Megha.

[tom_usenet]

On 15 Oct 2003 03:08:52 -0700, vm****@vsnl.com (Megha Vishwanath)
wrote:

Hi,

I'd like to know how heap aggregates created with a "new" operator at
You mean the new[] operator?
non-contiguous memory locations get deallocated using the "delete []"
operator in VC++.
There is a header before the bit of memory that new[] returns that
gives the size of the allocated block. A call to delete[] then uses
this size to
a) work out how many objects to destruct
b) actually deallocate the memory
A garbage collectors in Java deallocate on the basis of a record
maintained during the "new" allocation.
Same in C++ - the memory allocator keeps track of the size of
allocations. Different allocators do this differently.

Do we use something like a garbage collector to maintain arecord of
the heap memory start indexes.

No. You should read up on memory allocators:

http://www.memorymanagement.org

Tom

[Rolf Magnus]

tom_usenet wrote:

On 15 Oct 2003 03:08:52 -0700, vm****@vsnl.com (Megha Vishwanath)
wrote:

Hi,

I'd like to know how heap aggregates created with a "new" operator at

You mean the new[] operator?

non-contiguous memory locations get deallocated using the "delete []"
operator in VC++.

There is a header before the bit of memory that new[] returns that
gives the size of the allocated block. A call to delete[] then uses
this size to
a) work out how many objects to destruct
b) actually deallocate the memory

Just to mention: That's one way to do it. The C++ standard doesn't
specify how this is to be done, and there are other ways.

[Megha Vishwanath]

Thanx Tom!