Now that we've designed data structures, properties, and methods for PhBook, it is time to begin writing code. Our next steps are to add the definition of NAME_SIZ and PhRec into PhBook.idl because both the client and the server use these definitions.
NAME_SIZ and PhRec must be manually added into PhBook.idl. Adding the following code to PhBook.idl just below import ocidl.idl and above the attributes section does this:

cpp_quote("#define NAME_SIZ 80")
#define NAME_SIZ 80
typedef struct {
  TCHAR firstName[NAME_SIZ];
  TCHAR lastName[NAME_SIZ];
  TCHAR phNumber[NAME_SIZ];
} PhRec;

The cpp_quote directive tells MIDL (the IDL compiler) not to compile the enclosed string. Instead, the string should be passed through into output file PhRec.h. cpp_quote directives are commonly used by developers to place constants, macros, and comments into the include file created by MIDL.
The #define NAME_SIZ 80, not enclosed within cpp_quote, is used by MIDL as a constant.
After compiling the definitions above, MIDL generates the following code, placing it in PhRec.h:

#define NAME_SIZ 80
typedef /* [public] */ struct
   __MIDL___MIDL_itf_PhBook_0000_0001
   
    {
    TCHAR firstName[ 80 ];
    TCHAR lastName[ 80 ];
    TCHAR phNumber[ 80 ];
    } PhRec;

In the next lessons, we will add properties CurRec, MaxRecs, and NumRecs and methods IReadPhBook::GetPhoneRec, IManagePhBook::AddRec, and IManagePhBook::DeleteRec. These can be added using Visual C++ support.

Click the Exercise link below to apply what you've learned about adding structures and constants.
Add IDL Definitions - Exercise