I always forget this one, so better keep a reminder here 
How to display a C preprocessor output message:
Board index Utilities / Utilidades #pragma message
Checking several preprocessor defined values:
if defined( VALUE1 ) || defined( VALUE2 ) || ...
For VC use pragma message like this:
#pragma message( "Here!" )
https://docs.microsoft.com/en-us/cpp/preprocessor/message?view=vs-2019
#pragma message( "Here!" )
https://docs.microsoft.com/en-us/cpp/preprocessor/message?view=vs-2019