🚀 go-pugleaf

What follows came from one of my users...


>// A class that has no data members should have a size of zero so that 
>// classes that are derived from it aren't needlessly expanded in size.
>// This would not normally be a problem, but my program allocates almost
>// 250,000 small derived class elements, and the base class being a non-
>// zero size bloats the required memory by a megabyte.
>
>// If the empty base class cannot be made size zero because of implementation
>// restrictions, at least the derived class should not be made bigger.  An
>// increase of an eight-byte element to twelve bytes is a 50% overhead.
>
>#include <iostream.h>
>#include <stddef.h>
>
>class NeverFreed {      // special memory management strategy for
>public:                 // data elements that are never freed
>        void *operator new(size_t);
>};
>
>class Derived : public NeverFreed
>{                       // on a 32-bit machine, this should be eight bytes
>        Derived *next;
>        long item;
>};
>
>int
>main(void)
>{
>        if (sizeof(class Derived) == 8)
>                return 0;
>        cout    << "The size of an empty class is "
>                << sizeof(class NeverFreed)
>                << " and the derived class "
>                << sizeof(class Derived)
>                << endl;
>        return 1;
>}