what does it mean typedef char *b?

I'm reading through this memory management code overloading operator new. there's expression something like

typedef char *b

and later in the code b was used like this:

b(h); //h is a pointer to some class;

h defined here:

static Head* h= (Head*) HEAP_BASE_ADDRESS;

I'm assuming when b is used it is considered a pointer to a char. But how can a pointer have expressions like b()?? Is there some sort of conversion going on in here? Can I understand it as b now is having the same address as h?