Help need with conditional assembling few lines of assembly code on TMS320vc5470 using ccs 3.3

#ifdef APP

some code

#else

some other code

#endif

i have tried

 Example:
     ------------------------------------------------------------
                                                       myheader.h

        #define WANT_ID 1
        #define NAME "John\n"

        extern int a_variable;
        extern float cvt_integer(int src);

        struct myCstruct { int member_a; float member_b; };

        enum status_enum { OK = 1, FAILED = 256, RUNNING = 0 };
 
     ------------------------------------------------------------
                                                        myasm.asm
              .cdecls C,LIST,"myheader.h"

     size:    .int $sizeof(myCstruct)
     aoffset: .int myCstruct.member_a
     boffset: .int myCstruct.member_b

     okvalue: .int status_enum.OK
     failval: .int status_enum.FAILED

              .if $defined(WANT_ID)
     id       .cstring NAME
              .endif

 but i am getting error mentioning

[E0004] Absolute, well-defined
        integer value expected

if someone can share small code snippet how to assembly different lines of assembly code based on a macro, it would be of great help.

Regards,

Avinash