typedef problem vs c++

xxx.h has
#define EXTERNAL WINAPI
#define RFAR far
.....
.......
yy.h has
#include xxx.h

typedef unsigned short RDM_SESS
.....
.......
typedef void(EXTERNAL *ERRORPROC)(short,RDM_SESS,void RFAR*);

this last line is causing compile errors ( vs 2010) like RFAR illegal use of type void

Don't use uppercase names for anything other than macro names.

Then you won't get caught out by having symbols you use (which aren't macros) being randomly replaced because someone chooses to define something like RFAR.

The issue of name clashes with macros aside, I suspect the problem is that modern compilers do not use or recognise far pointer types.