undefining a struct

Hi,

I wanted to know if it is possible to undefine a struct.
I want to merge to codes, the old one has a struct that it uses,
but the new code is based on a modified version of this struct.

I wondered if I can undefine the "old" struct and then to re-define
the new struct.


Thanks.

 

in .h file write
#define struct Mystruct

and in .c or Cpp file write

#undef struct