FILE: Enum_MODE.IDL
    //@copy  /*********************************************************************
    //@copy  * Generated from class code EnumXLAT_MODE (DCS Corp)
    //@copy  *********************************************************************/

      enum MODE_ID_Type {
        MODE_UNDEFINED,
        MODE_POWER_UP,
        MODE_OPERATIONAL,
        MODE_MAINT_DIAGNOSTICS,
        MODE_MAINT_RECONFIGURATION,
        MODE_NOT_USED
      };
  
FILE: SEED.idl
      #include "Enum_MODE.idl"
      module Seed
      {
         struct Msg
         {
            long seedval;
            MODE_ID_Type mt;
         };
      };
      //-[Reliability = Reliable]
      //-[Deadline_Duration = Infinite]   
      //-[Durability = Transient_Local]
      //-[Lifespan_Duration = {3, 0}]
      //-[Ownership = Shared]
      //-[History_Depth = 1]
      //-[Reader_Lifecycle_Duration = Infinite]
      //-[Writer_Autodispose_Instances = true]

FILE SEED.BAT
      @call vcvars32.bat
      @echo off
      set dir=%~dp0
      echo dir=%dir%
      set idlfolder=C:/testfolder/mrap/idl
      echo idlfolder=%idlfolder%
      set code_out=%dir%dds_implementation
      echo code_out=%code_out%
      echo NDDSHOME=%NDDSHOME%
      set batch_script="%NDDSHOME%\bin\rtiddsgen.bat"
      echo batch_script=%batch_script%
      echo .
      dir %code_out%
      del %code_out%\*.*
      echo pausing after file delete
      pause
      cd %NDDSHOME%\bin"
      call vcvars32.bat
      set idlpreprocopt=-ppOption /nologo -ppOption /C -ppOption /E -ppOption /X
      set idlpreprocpath=-ppPath "%VCINSTALLDIR%bin\cl.exe"
      echo %idlpreprocpath%
      echo %idlpreprocopt%
      echo %batch_script% %idlpreprocpath% %idlpreprocopt% -d %code_out% -I %idlfolder% %idlfolder%/Enum_MODE.idl
      echo %batch_script% %idlpreprocpath% %idlpreprocopt% -d %code_out% -I %idlfolder% %idlfolder%/Seed.idl
      pause
      call %batch_script% %idlpreprocpath% %idlpreprocopt% -d %code_out% -I %idlfolder% %idlfolder%/Enum_MODE.idl
      pause
      call %batch_script% %idlpreprocpath% %idlpreprocopt% -d %code_out% -I %idlfolder% %idlfolder%/Seed.idl
      echo done rtiddsgen
      pause
      
SCREEN OUTPUT (Windows CMD window Note: Line numbers 21, 54, and 81 are echo text I added to instrument RTIDDSGEN.BAT to determine the executing part of the batch command)
    -ppPath "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\cl.exe"
    -ppOption /nologo -ppOption /C -ppOption /E -ppOption /X
    "C:\Program Files\rti_connext_dds-5.2.0\bin\rtiddsgen.bat" -ppPath "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\cl.exe" -ppOption /nologo -ppOption /C -ppOption /E -ppOption /X -d C:\te
    stfolder\mrap\idl\dds_implementation -I C:/testfolder/mrap/idl C:/testfolder/mrap/idl/Enum_MODE.idl
    "C:\Program Files\rti_connext_dds-5.2.0\bin\rtiddsgen.bat" -ppPath "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\cl.exe" -ppOption /nologo -ppOption /C -ppOption /E -ppOption /X -d C:\te
    stfolder\mrap\idl\dds_implementation -I C:/testfolder/mrap/idl C:/testfolder/mrap/idl/Seed.idl
    Press any key to continue . . .
    line 21
    line 54
    runRtiddsgen1=false
    line 81
    INFO com.rti.ndds.nddsgen.Main Running rtiddsgen version 2.3.0, please wait ...
    rtiddsgen20_122588262222060142.cc
    INFO com.rti.ndds.nddsgen.Main Done
    end of batch file
    Press any key to continue . . .
    line 21
    line 54
    runRtiddsgen1=false
    line 81
    INFO com.rti.ndds.nddsgen.Main Running rtiddsgen version 2.3.0, please wait ...
    rtiddsgen20_4092114859511790248.cc
    C:\\testfolder\\mrap\\idl\\Seed.idl line 1:0 no viable alternative at character 'ï'
    C:\\testfolder\\mrap\\idl\\Seed.idl line 1:1 no viable alternative at character '»'
    C:\\testfolder\\mrap\\idl\\Seed.idl line 1:2 no viable alternative at character '¿'
    WARN com.rti.ndds.nddsgen.antlr.auto.IdlLexer C:\\testfolder\\mrap\\idl\\Seed.idl line 1  the usage of the '#include' directive in combination with the '-ppDisable' command-line option may lead to com
    pilation errors. Consider removing the '-ppDisable' command-line option.
    ERROR com.rti.ndds.nddsgen.Main Seed.idl line 7:6 member type 'MODE_ID_Type' not found
    ERROR com.rti.ndds.nddsgen.Main Fail:  The file couldn't be parsed and the rawTree wasn't generated
    INFO com.rti.ndds.nddsgen.Main Done (failures)
    end of batch file
    done rtiddsgen
    Press any key to continue . . .
    
ODD STUFF I DO NOT COMPREHEND:
a. the output about "no viable alternative at character"
b. With or without my use of -ppPath and -ppOption, I get the same WARN about the #include not compatible with -ppDisable but I don't use -ppDisable
c. Why the MODE_ID_Type is not found, unless it derives from the earlier warning and the #include never got processed.