Error directive
From cppreference.com
                    
                                        
                    < cpp | preprocessor
                    
                                                            
                    Shows given message and renders program ill-formed.
[edit] Syntax
| #errorerror_message | |||||||||
[edit] Explanation
After encountering #error directive, diagnostic message error_message is shown and the program is rendered ill-formed (the compilation is stopped). 
error_message can consist of several words not necessarily in quotes.


