Re: This HAS to be UB...

Chris M. Thomasson wrote:


  That code can be simplified further. Using VC9, this

     #include <cstdio>
     #include <cstdlib>
     #include <new>

     void* allocate(std::size_t size) throw(std::bad_alloc) {
         void* const mem = ::operator new(size);
         std::printf("allocate(%p, %lu)\n", (void*)mem, (unsigned long)size);
         return mem;
     }

     void deallocate(void* const mem, std::size_t size) throw() {
         std::printf("deallocate(%p, %lu)\n", (void*)mem, (unsigned long)size);
         if (mem) ::operator delete(mem);
     }

     struct buf2 {
         char mem[1024];
         void* operator new(std::size_t size) throw(std::bad_alloc) {
             return allocate(size);
         }

         void* operator new[](std::size_t size) throw(std::bad_alloc) {
             return allocate(size);
         }

         void operator delete(void* mem, std::size_t size) throw() {
             deallocate(mem, size);
         }

         void operator delete [](void* mem, std::size_t size) throw() {
             deallocate(mem, size);
         }
     };

     int main() {
         buf2* b = new buf2;
         delete b;

         b = new buf2[5];
         delete [] b;

         return 0;
     }

  shows the same behavior for me.

  Debugging shows that VC9 doesn't call 'operator new[]' for 'new buf2[5]'
  (it calls 'operator new' instead), but calls 'operator delete[]' for
  'delete[] b'.
  Either I'm missing something really obvious, or that's a plain bug.


  Schobi