What is the meaning of `struct X typedef` vs. `typedef struct X`?

Question

I have the following (working) code in an existing code base, used in include file that is shared between C and C++, compiling on MSVC (2010) and Windows DDK:

Answer 1

Both have the same meaning. Both of these two forms are valid:

typedef  
 typedef    

You can typedef the above struct in either ways:

struct X {
    USHORT x;
}typedef X, *PX;     //  typedef  

or

typedef struct {
    USHORT x;
} X, *PX;            // typedef