C - Design your own free( ) function

Question

Today, I appeared for an interview and the interviewer asked me this,

1. Tell me the steps how will you design your own f

Answer 1

Tell me the steps how will you design your own free( ) function for deallocate the allocated memory.

#include 
#undef free
#define free(X) my_free(X)

inline void my_free(void *ptr) { }

How can it be more efficient than C's default free() function ?

It is extremely fast, requiring zero machine cycles. It also makes use-after-free bugs go away. It's a very useful free function for use in programs which are instantiated as short-lived batch processes; it can usefully be deployed in some production situations.

What can you conclude ?

I really want this job, but in another company.