struct PK_MEMORY_frustrum_s
    {
    PK_MEMORY_alloc_f_t alloc_fn;                 --- registered allocator
    PK_MEMORY_free_f_t free_fn;                   --- registered free function
    };
typedef struct PK_MEMORY_frustrum_s PK_MEMORY_frustrum_t;



This data structure holds pointers to the memory handling functions the
application wishes to register with the PK using PK_MEMORY_register_callbacks.


The functions should be type compatible with malloc and free in the standard
C run-time library.