Is APSTUDIO_INVOKED stuff necessary in a resource file header that generated by Visual Studio?

Visual Studio generates resource.h when creating a new .rc file.

Here is the generated file looks like:

   #ifdef APSTUDIO_INVOKED  
   # ifndef APSTUDIO_READONLY_SYMBOLS  
   #  define _APS_NEXT_RESOURCE_VALUE        102  
   #  define _APS_NEXT_COMMAND_VALUE         40001  
   #  define _APS_NEXT_CONTROL_VALUE         1001  
   #  define _APS_NEXT_SYMED_VALUE           102  
   # endif  
   #endif  

I have tried to compile and run without these stuff, it works perfectly like nothing is changed.

So, what are these stuff? Is it necessary to define it?

Probably Visual Studio uses it for incremental identifier for "next resource"?
However, I manually editing the .rc file, so I didn't use VS' resource manager...