I think that DMC's delete tries to free the memory which is not dynamically allocated, in case of using placement new.  The following program crashes (-mn) or terminates with a "heap corruption" message (-mx).  This is true also for placement new[], the sample code is almost the same, so I won't provide it here.  The destructors should be executed, but the memory shouldn't be freed, because it wasn't allocated by new (the object was contructed directly at the user supplied address).

// placement new demo (sc -mn -A)
#include <new.h>
class A {}

int main()
{
  static char buffer[1024];
  A *pa = new (static_cast<A *>(buffer)) A;
  delete pa; // it crashes here
  return 0;
}

An extra note: ISO-C++ standard says that main must be declared as returning int, and that if the program doesn't return a value from main, a "0" must be silently returned by the compiler (in the special case of main only!).  DMC gives a warning in normal mode, and an error in ANSI mode, if the "return 0;" line is missing.

Regards,
  Laurentiu

Errr... my mistake, sorry!  Normally, one should call pa->~A(); what I wrongly thought is that this call is a mere method call, and, if A is derived from B, B's destructor doesn't get called.  I was confused about gcc and BCC supporting calls to delete with pointers to objects obtained via placement new.  I guess this is just an extension of the standard (I don't have a copy of it).

Sorry about this!

Laurentiu

"Laurentiu Pancescu" <user@domain.invalid> schrieb im Newsbeitrag news:a75lrs$2deg$1@digitaldaemon.com...
> // placement new demo (sc -mn -A)
> #include <new.h>
> class A {}
>
> int main()
> {
>   static char buffer[1024];
>   A *pa = new (static_cast<A *>(buffer)) A;
>   delete pa; // it crashes here
pa -> ~A(); // this is the correct way, DMC handles it correctly
>   return 0;
> }

"Laurentiu Pancescu" <user@domain.invalid> wrote in message news:a75lrs$2deg$1@digitaldaemon.com...
> An extra note: ISO-C++ standard says that main must be declared as
returning
> int, and that if the program doesn't return a value from main, a "0" must
be
> silently returned by the compiler (in the special case of main only!).
DMC
> gives a warning in normal mode, and an error in ANSI mode, if the "return 0;" line is missing.

I'll fix that one, too. -Walter