Re: Operator delete question

Andrey Tarasevich <>
Fri, 09 Oct 2009 13:30:14 -0700
snapwink wrote:

int main()
  ISocket *pISock = static_cast <ISocket *> (new TCPSocket());
  return 0;

Compiling with GCC and running this, I am getting the expected
my malloc
Socket: Ctor
TCPSock: Ctor
TCPSock: Dtor
Socket: Dtor
my free

However, compiling with my embedded compiler, I get different results:
after "Socket: Dtor", the global operator delete is getting called
(instead of the one I overloaded). I want to understand what does C++
standard say about this, or is this dependent on compilers?

It is not supposed to be dependent on the compiler. The standard says
that a concrete version of overloaded 'operator delete' should be chosen
as if it was looked up from the destructor of the object being destroyed
(i.e. from the "topmost" destructor). In your case everything seems to
be fine with virtual destructors and the correct destructor is indeed
called by the compiler. GCC also selects the proper 'operator delete'.

Meanwhile, your embedded compiler seems to work incorrectly.

It would be interesting to make an extra experiment and see which
'operator delete' your embedded compiler would call if you just deleted
the object immediately with an explicit delete-expression right in 'main'

   ISocket *pISock = static_cast <ISocket *> (new TCPSocket());
   delete pISock;

just to check if it is somehow confused by a more "convoluted" method of
deletion through 'delete this' used in your original code.

Best regards,
Andrey Tarasevich

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